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Slany, Michal, Petr Jezek, Vera Fiserova, Monika Bodnarova, Jiri Stork, Marta Havelkova, Frantisek Kalat i Ivo Pavlik. "Mycobacterium marinum infections in humans and tracing of its possible environmental sources". Canadian Journal of Microbiology 58, nr 1 (styczeń 2012): 39–44. http://dx.doi.org/10.1139/w11-104.
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The low frequency of nontuberculous mycobacterial infections, nonspecific symptoms for individual mycobacteria, and the lack of specific identification methods could alter correct diagnosis. This study presents a combined microbiology and molecular-based approach for Mycobacterium marinum detection in four aquarists with cutaneous mycobacterial infection. Simultaneously, ecology screening for M. marinum presence in the aquarists’ fish tanks was performed. A total of 38 mycobacterial isolates originated from four human patients (n = 20), aquarium animals (n = 8), and an aquarium environment (n = 10). Isolate identification was carried out using 16S rRNA sequence analysis. A microbiology-based approach, followed by 16S rRNA sequence analysis, was successfully used for detection of M. marinum in all four patients. Animal and environmental samples were simultaneously examined, and a total of seven mycobacterial species were isolated: Mycobacterium chelonae , Mycobacterium fortuitum , Mycobacterium gordonae , Mycobacterium kansasii , Mycobacterium mantenii , Mycobacterium marinum , and Mycobacterium peregrinum . The presence of M. marinum was proven in the aquarium environments of two patients. Although M. marinum is described as being present in water, it was detected only in fish.
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Song, Chang-Hwa, Ji-Sook Lee, Hwa-Jung Kim, Jeong-Kyu Park, Tae-Hyun Paik i Eun-Kyeong Jo. "Interleukin-8 Is Differentially Expressed by Human-Derived Monocytic Cell Line U937 Infected with Mycobacterium tuberculosis H37Rv and Mycobacterium marinum". Infection and Immunity 71, nr 10 (październik 2003): 5480–87. http://dx.doi.org/10.1128/iai.71.10.5480-5487.2003.
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ABSTRACT Although Mycobacterium marinum is closely related to Mycobacterium tuberculosis H37Rv genomically, the clinical outcome in humans is quite different for M. marinum and M. tuberculosis infections. We investigated possible factors in the host macrophages for determining differential pathological responses to M. tuberculosis and M. marinum using an in vitro model of mycobacterial infection. Using suppression-subtractive hybridization, we identified 12 differentially expressed genes in the human monocytic cell line U937 infected with M. tuberculosis and M. marinum. Of those genes, the most frequently recovered transcript encoded interleukin-8 (IL-8). Northern hybridization revealed that IL-8 mRNA was highly upregulated in M. tuberculosis-infected U937 cells compared with M. marinum-infected cells. In addition, enzyme-linked immunosorbent assay showed that IL-8 protein secretion was significantly elevated in M. tuberculosis-infected U937 cells, human primary monocytes, and monocyte-derived macrophages compared with that in M. marinum-infected cells. The depressed IL-8 expression was unique in M. marinum-infected cells compared with cells infected with other strains of mycobacteria, including M. tuberculosis H37Ra, Mycobacterium bovis BCG, or Mycobacterium smegmatis. When the expression of NF-κB was assessed in mycobacterium-infected U937 cells, IκBα proteins were significantly degraded in M. tuberculosis-infected cells compared with M. marinum-infected cells. Collectively, these results suggest that differential IL-8 expression in human macrophages infected with M. tuberculosis and M. marinum may be critically associated with distinct host responses in tuberculosis. Additionally, our data indicate that differential signal transduction pathways may underlie the distinct patterns of IL-8 secretion in cells infected by the two mycobacteria.
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El-Etr, Sahar H., Ling Yan i Jeffrey D. Cirillo. "Fish Monocytes as a Model for Mycobacterial Host-Pathogen Interactions". Infection and Immunity 69, nr 12 (1.12.2001): 7310–17. http://dx.doi.org/10.1128/iai.69.12.7310-7317.2001.
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ABSTRACT Mycobacterium marinum, a relatively rapid-growing fish and human pathogen, has become an important model for the investigation of mycobacterial pathogenesis. M. marinumis closely related to the Mycobacterium tuberculosiscomplex and causes a disease in fish and amphibians with pathology similar to tuberculosis. We have developed an in vitro model for the study of M. marinum virulence mechanisms using the carp monocytic cell line CLC (carp leukocyte culture). We found that fish monocytes can differentiate between pathogenic and nonpathogenic mycobacterial species. Interestingly, M. marinum enters fish monocytes at a 40- to 60-fold-higher rate thanMycobacterium smegmatis. In addition, M. marinum survives and replicates in fish monocytes whileM. smegmatis is killed. We also found that M. marinum inhibits lysosomal fusion in fish monocytes, indicating that these cells may be used to dissect the mechanisms of intracellular trafficking in mycobacteria. We conclude from these observations that monocytic cells from fish, a natural host for M. marinum, provide an extremely valuable model for the identification and characterization of mycobacterial virulence determinants in the laboratory.
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Stragier, Pieter, Anthony Ablordey, Wayne M. Meyers i Françoise Portaels. "Genotyping Mycobacterium ulcerans and Mycobacterium marinum by Using Mycobacterial Interspersed Repetitive Units". Journal of Bacteriology 187, nr 5 (1.03.2005): 1639–47. http://dx.doi.org/10.1128/jb.187.5.1639-1647.2005.
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ABSTRACT A novel category of variable tandem repeats (VNTR) called mycobacterial interspersed repetitive units (MIRUs) has been identified for Mycobacterium ulcerans (n = 39), M. marinum (n = 27), and one related organism. Fifteen MIRU loci were identified in the genome of M. marinum and were used to genotype M. ulcerans, M. marinum, and an M. marinum-like organism that is considered a possible missing link between M. marinum and M. ulcerans. Seven MIRU loci were polymorphic, and locus-specific PCRs for four of these loci differentiated seven M. ulcerans genotypes, four M. marinum genotypes, and a unique genotype for the missing link organism. The seven M. ulcerans genotypes were related to six different geographic origins of isolates. All isolates from West and Central Africa, including old and recent isolates, belonged to the same genotype, emphasizing the great spatiotemporal homogeneity among African isolates. Unlike the M. ulcerans genotypes, the four M. marinum genotypes could not be clearly related to the geographic origins of the isolates. According to MIRU-VNTR typing, all M. ulcerans and M. marinum isolates of American origin were closely related, suggesting a common American ancestor for these two pathogenic species on the American continents. MIRU typing has significant potential value for discriminating between reoccurrence and reinfection for M. ulcerans disease.
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Pagán-Ramos, E., J. Song, M. McFalone, M. H. Mudd i V. Deretic. "Oxidative Stress Response and Characterization of theoxyR-ahpC and furA-katG Loci inMycobacterium marinum". Journal of Bacteriology 180, nr 18 (15.09.1998): 4856–64. http://dx.doi.org/10.1128/jb.180.18.4856-4864.1998.
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ABSTRACT Oxidative stress response in pathogenic mycobacteria is believed to be of significance for host-pathogen interactions at various stages of infection. It also plays a role in determining the intrinsic susceptibility to isoniazid in mycobacterial species. In this work, we characterized the oxyR-ahpC and furA-katG loci in the nontuberculous pathogen Mycobacterium marinum. In contrast to Mycobacterium smegmatis and likeMycobacterium tuberculosis and Mycobacterium leprae, M. marinum was shown to possess a closely linked and divergently oriented equivalents of the regulator of peroxide stress response oxyR and its subordinate geneahpC, encoding a homolog of alkyl hydroperoxide reductase. Purified mycobacterial OxyR was found to bind to theoxyR-ahpC promoter region from M. marinum and additional mycobacterial species. Mobility shift DNA binding analyses using OxyR binding sites from several mycobacteria and a panel of in vitro-generated mutants validated the proposed consensus mycobacterial recognition sequence. M. marinum AhpC levels detected by immunoblotting, were increased upon treatment with H2O2, in keeping with the presence of a functional OxyR and its binding site within the promoter region ofahpC. In contrast, OxyR did not bind to the sequences upstream of the katG structural gene, and katGexpression did not follow the pattern seen with ahpC. Instead, a new open reading frame encoding a homolog of the ferric uptake regulator Fur was identified immediately upstream ofkatG in M. marinum. The furA-katGlinkage and arrangement are ubiquitous in mycobacteria, suggesting the presence of additional regulators of oxidative stress response and potentially explaining the observed differences in ahpC andkatG expression. Collectively, these findings broaden our understanding of oxidative stress response in mycobacteria. They also suggest that M. marinum will be useful as a model system for studying the role of oxidative stress response in mycobacterial physiology, intracellular survival, and other host-pathogen interactions associated with mycobacterial diseases.
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Dionne, Marc S., Nafisa Ghori i David S. Schneider. "Drosophila melanogaster Is a Genetically Tractable Model Host for Mycobacterium marinum". Infection and Immunity 71, nr 6 (czerwiec 2003): 3540–50. http://dx.doi.org/10.1128/iai.71.6.3540-3550.2003.
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ABSTRACT Mycobacterium marinum is a pathogenic mycobacterial species that is closely related to Mycobacterium tuberculosis and causes tuberculosis-like disease in fish and frogs. We infected the fruit fly Drosophila melanogaster with M. marinum. This bacterium caused a lethal infection in the fly, with a 50% lethal dose (LD50) of 5 CFU. Death was accompanied by widespread tissue damage. M. marinum initially proliferated inside the phagocytes of the fly; later in infection, bacteria were found both inside and outside host cells. Intracellular M. marinum blocked vacuolar acidification and failed to colocalize with dead Escherichia coli, similar to infections of mouse macrophages. M. marinum lacking the mag24 gene were less virulent, as determined both by LD50 and by death kinetics. Finally, in contrast to all other bacteria examined, mycobacteria failed to elicit the production of antimicrobial peptides in Drosophila. We believe that this system should be a useful genetically tractable model for mycobacterial infection.
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El-Etr, Sahar H., Selvakumar Subbian, Suat L. G. Cirillo i Jeffrey D. Cirillo. "Identification of Two Mycobacterium marinum Loci That Affect Interactions with Macrophages". Infection and Immunity 72, nr 12 (grudzień 2004): 6902–13. http://dx.doi.org/10.1128/iai.72.12.6902-6913.2004.
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ABSTRACT Mycobacterium marinum is closely related to Mycobacterium tuberculosis, the cause of tuberculosis in humans. M. marinum has become an important model system for the study of the molecular mechanisms involved in causing tuberculosis in humans. Through molecular genetic analysis of the differences between pathogenic and nonpathogenic mycobacteria, we identified two loci that affect the ability of M. marinum to infect macrophages, designated mel 1 and mel 2. In silico analyses of the 11 putative genes in these loci suggest that mel 1 encodes secreted proteins that include a putative membrane protein and two putative transglutaminases, whereas mel 2 is involved in secondary metabolism or biosynthesis of fatty acids. Interestingly, mel 2 is unique to M. marinum and the M. tuberculosis complex and not present in any other sequenced mycobacterial species. M. marinum mutants with mutations in mel 1 and mel 2, constructed by allelic exchange, are defective in the ability to infect both murine and fish macrophage cell lines. These data suggest that the genes in mel 1 and mel 2 are important for the ability of M. marinum to infect host cells.
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Talaat, Adel M., Renate Reimschuessel, Steven S. Wasserman i Michele Trucksis. "Goldfish, Carassius auratus, a Novel Animal Model for the Study of Mycobacterium marinumPathogenesis". Infection and Immunity 66, nr 6 (1.06.1998): 2938–42. http://dx.doi.org/10.1128/iai.66.6.2938-2942.1998.
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ABSTRACT We have developed an animal model for studying mycobacterial pathogenesis using Mycobacterium marinum and the goldfish,Carassius auratus. Goldfish are injected intraperitoneally with doses between 102 and 109 CFU of M. marinum organisms. Depending on the dose of M. marinum organisms administered, an acute or chronic disease is produced. The acute disease is characterized by systemic mycobacterial infection, severe peritonitis, tissue necrosis, and a short median survival time. The chronic disease is characterized by granuloma formation in all organs and survival of animals to the end point of the experiment (56 days). Colony counts in organ homogenates showed recovery of mycobacteria from a high percentage of inoculated animals. We believe this well-characterized animal model will be useful for studying mycobacterial pathogenesis.
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Rybniker, Jan, Martina Wolke, Christiane Haefs i Georg Plum. "Transposition of Tn5367 in Mycobacterium marinum, Using a Conditionally Recombinant Mycobacteriophage". Journal of Bacteriology 185, nr 5 (1.03.2003): 1745–48. http://dx.doi.org/10.1128/jb.185.5.1745-1748.2003.
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ABSTRACT Mycobacterium marinum is a close relative of the obligate human pathogen Mycobacterium tuberculosis. As with M. tuberculosis, M. marinum causes intracellular infection of poikilothermic vertebrates and skin infection in humans. It is considered a valid model organism for the study of intracellular pathogenesis of mycobacteria. Low transformation efficiencies for this species have precluded approaches using mutant libraries in pathogenesis studies. We have adapted the conditionally replicating mycobacteriophage phAE94, originally developed as a transposon mutagenesis tool for M. tuberculosis, to meet the specific requirements of M. marinum. Conditions permissive for phage replication in M. tuberculosis facilitated highly efficient transposon delivery in M. marinum. Using this technique we succeeded in generating a representative mutant library of this species, and we conclude that TM4-derived mycobacteriophages are temperature-independent suicide vectors for M. marinum.
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Saadatmand, Babak, James Kevin Poulton i Catharine Lisa Kauffman. "Mycobacterium Marinum with Associated Bursitis". Journal of Cutaneous Medicine and Surgery 3, nr 4 (kwiecień 1999): 218–20. http://dx.doi.org/10.1177/120347549900300413.
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Background: Mycobacterium marinum infections have been reported for over 50 years, mostly in association with trauma in the setting of water exposure. Objective: The differential diagnosis for nodules in a sporotrichoid distribution with simultaneous bursitis is discussed. Mycobacterium marinum treatment regimens for skin and joint involvement are reviewed. Methods: Mycobacterium marinum was identified by skin tissue culture with Lowenstein-Jensen medium at 32°C. Histopathologic findings support mycobacterial infection. Results: Bursitis and nodules resolved in the first 2 months of a 6-month course of minocycline treatment. Conclusion: Bursitis is an extremely rare but significant complication of M. marinum.
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Gupta, Tuhina, Kari Fine-Coulson, Russell Karls, David Gauthier i Frederick Quinn. "Internalization ofMycobacterium shottsiiandMycobacterium pseudoshottsiibyAcanthamoeba polyphaga". Canadian Journal of Microbiology 59, nr 8 (sierpień 2013): 570–76. http://dx.doi.org/10.1139/cjm-2013-0079.
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Amoebae serve as environmental hosts to a variety of mycobacteria, including Mycobacterium avium and Mycobacterium marinum. Mycobacterium shottsii and Mycobacterium pseudoshottsii are waterborne species isolated from the spleens and dermal lesions of striped bass (Morone saxatilis) from the Chesapeake Bay. The optimal growth temperature for these fish isolates is 25 °C. In the present study, amoebae were examined as a potential environmental reservoir for these fish pathogens. Several studies demonstrated that M. avium bacilli replicate within the trophozoite stage and reside in large numbers within the cytosol of the cyst of the free-living amoeba Acanthamoeba polyphaga. Results from the present study showed that M. shottsii, M. pseudoshottsii, and M. marinum bacilli were internalized by A. polyphaga trophozoites within 6 h but that intracellular viability decreased by 2 to 3 logs over 10 days. While an average of 25 M. marinum bacilli were identified by electron microscopy in the cytosol of the cyst, <5 M. pseudoshottsii and no M. shottsii bacilli were observed in this location. All Mycobacterium species examined remained viable but did not replicate after encystment and subsequent 48 h incubation in 4% HCl. This concentration of HCl will kill mycobacteria but will not enter amoebal cysts. Bacterial viability studies within stages of the amoeba life cycle indicate fewer M. shottsii and M. pseudoshottsii bacilli within the trophozoite and cyst stages relative to M. marinum.
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Ranger, Brian S., Engy A. Mahrous, Lydia Mosi, Sarojini Adusumilli, Richard E. Lee, Angelo Colorni, Martha Rhodes i P. L. C. Small. "Globally Distributed Mycobacterial Fish Pathogens Produce a Novel Plasmid-Encoded Toxic Macrolide, Mycolactone F". Infection and Immunity 74, nr 11 (21.08.2006): 6037–45. http://dx.doi.org/10.1128/iai.00970-06.
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ABSTRACT Mycobacterium ulcerans and Mycobacterium marinum are closely related pathogens which share an aquatic environment. The pathogenesis of these organisms in humans is limited by their inability to grow above 35°C. M. marinum causes systemic disease in fish but produces localized skin infections in humans. M. ulcerans causes Buruli ulcer, a severe human skin lesion. At the molecular level, M. ulcerans is distinguished from M. marinum by the presence of a virulence plasmid which encodes a macrolide toxin, mycolactone, as well as by hundreds of insertion sequences, particularly IS2404. There has been a global increase in reports of fish mycobacteriosis. An unusual clade of M. marinum has been reported from fish in the Red and Mediterranean Seas and a new mycobacterial species, Mycobacterium pseudoshottsii, has been cultured from fish in the Chesapeake Bay, United States. We have discovered that both groups of fish pathogens produce a unique mycolactone toxin, mycolactone F. Mycolactone F is the smallest mycolactone (molecular weight, 700) yet identified. The core lactone structure of mycolactone F is identical to that of M. ulcerans mycolactones, but a unique side chain structure is present. Mycolactone F produces apoptosis and necrosis on cultured cells but is less potent than M. ulcerans mycolactones. Both groups of fish pathogens contain IS2404. In contrast to M. ulcerans and conventional M. marinum, mycolactone F-producing mycobacteria are incapable of growth at above 30°C. This fact is likely to limit their virulence for humans. However, such isolates may provide a reservoir for horizontal transfer of the mycolactone plasmid in aquatic environments.
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Gao, Yaxian, Jiaqing Li, Xinya Guo, Liru Guan, Jie Wang, Xiaochen Huang, Wenjuan Wang i Hua Yang. "L-Tyrosine Limits Mycobacterial Survival in Tuberculous Granuloma". Pathogens 12, nr 5 (28.04.2023): 654. http://dx.doi.org/10.3390/pathogens12050654.
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Caused by the intracellular pathogen Mycobacterium tuberculosis (Mtb), tuberculosis (TB) remains a massive global public health issue. A well-known and key TB trait is caseous necrotic granuloma, which allows mycobacteria to reactivate and disseminate, thus confounding TB eradication programs. Amino acid (AA) metabolism is key to regulating immune responses in Mtb infections; however, it is currently unclear if AAs can be used to treat tuberculous granulomas. Here, we screened 20 proteinogenic AAs using a Mycobacterium marinum-infected zebrafish granuloma model. Only L-tyrosine simultaneously reduced Mycobacterium marinum (M. marinum) levels in zebrafish larvae and adults and inhibited intracellular pathogen survival levels. Mechanistically, L-tyrosine significantly upregulated interferon-γ (IFN-γ) expression in M. marinum -infected zebrafish adults but not in larvae. Using N-acetylcysteine (NAC) to inhibit reactive oxygen species (ROS), L-tyrosine appeared to inhibit Mtb intracellular survival by promoting ROS production. Thus, L-tyrosine as a non-essential AA may reduce mycobacterial survival in both macrophages and tuberculous granulomas. Our research provides a platform for the clinical development of AAs for active or latent TB patients infected with drug-sensitive or drug-resistant Mtb.
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Yip, Marcus J., Jessica L. Porter, Janet A. M. Fyfe, Caroline J. Lavender, Françoise Portaels, Martha Rhodes, Howard Kator, Angelo Colorni, Grant A. Jenkin i Tim Stinear. "Evolution of Mycobacterium ulcerans and Other Mycolactone-Producing Mycobacteria from a Common Mycobacterium marinum Progenitor". Journal of Bacteriology 189, nr 5 (15.12.2006): 2021–29. http://dx.doi.org/10.1128/jb.01442-06.
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ABSTRACT It had been assumed that production of the cytotoxic polyketide mycolactone was strictly associated with Mycobacterium ulcerans, the causative agent of Buruli ulcer. However, a recent study has uncovered a broader distribution of mycolactone-producing mycobacteria (MPM) that includes mycobacteria cultured from diseased fish and frogs in the United States and from diseased fish in the Red and Mediterranean Seas. All of these mycobacteria contain versions of the M. ulcerans pMUM plasmid, produce mycolactones, and show a high degree of genetic relatedness to both M. ulcerans and Mycobacterium marinum. Here, we show by multiple genetic methods, including multilocus sequence analysis and DNA-DNA hybridization, that all MPM have evolved from a common M. marinum progenitor to form a genetically cohesive group among a more diverse assemblage of M. marinum strains. Like M. ulcerans, the fish and frog MPM show multiple copies of the insertion sequence IS2404. Comparisons of pMUM and chromosomal gene sequences demonstrate that plasmid acquisition and the subsequent ability to produce mycolactone were probably the key drivers of speciation. Ongoing evolution among MPM has since produced at least two genetically distinct ecotypes that can be broadly divided into those typically causing disease in ectotherms (but also having a high zoonotic potential) and those causing disease in endotherms, such as humans.
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Solomon, Jonathan M., Grace S. Leung i Ralph R. Isberg. "Intracellular Replication of Mycobacterium marinum within Dictyostelium discoideum: Efficient Replication in the Absence of Host Coronin". Infection and Immunity 71, nr 6 (czerwiec 2003): 3578–86. http://dx.doi.org/10.1128/iai.71.6.3578-3586.2003.
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ABSTRACT Mycobacterium marinum causes tuberculosis-like disease in fish and amphibians and has been used as a model mycobacterial species because of its rapid growth and less stringent containment requirements relative to other mycobacterial species. We demonstrate here that M. marinum grows within Dictyostelium discoideum cells, allowing the genetic analysis of host factors that may modulate the replication of mycobacterial species. Intracellular growth of M. marinum was shown to mimic the properties previously observed for growth within cultured phagocytes. A defined bacterial mutant defective for growth within phagocytic cells was shown to be similarly defective for growth within D. discoideum. To test the role of host coronin, which was previously hypothesized to positively modulate mycobacterial growth within mouse macrophages, a defined D. discoideum coronin mutant was analyzed. Surprisingly, the absence of coronin resulted in enhanced intracellular replication of M. marinum relative to the control wild-type strain. Consistent with previous observations, some phagosomes showed persistence of coronin about the surface of the compartment, but colocalization of the protein was far from uniform. We conclude that in D. discoideum factors other than coronin support intracellular replication of M. marinum.
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Jenkin, Grant A., Timothy P. Stinear, Paul D. R. Johnson i John K. Davies. "Subtractive Hybridization Reveals a Type I Polyketide Synthase Locus Specific to Mycobacterium ulcerans". Journal of Bacteriology 185, nr 23 (1.12.2003): 6870–82. http://dx.doi.org/10.1128/jb.185.23.6870-6882.2003.
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ABSTRACT Mycobacterium ulcerans causes Buruli ulcer, the third most prevalent mycobacterial infection of immunocompetent humans after tuberculosis and leprosy. Recent work has shown that the production by M. ulcerans of mycolactone, a novel polyketide, may partly explain the pathogenesis of Buruli ulcer. To search for the genetic basis of virulence in M. ulcerans, we took advantage of the close genetic relationship between M. ulcerans and Mycobacterium marinum by performing genomic suppressive subtractive hybridization of M. ulcerans with M. marinum. We identified several DNA fragments specific to M. ulcerans, in particular, a type I polyketide synthase locus with a highly repetitive modular arrangement. We postulate that this locus is responsible for the synthesis of mycolactone in M. ulcerans.
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Tønjum, T., D. B. Welty, E. Jantzen i P. L. Small. "Differentiation of Mycobacterium ulcerans, M. marinum, and M. haemophilum: Mapping of Their Relationships to M. tuberculosis by Fatty Acid Profile Analysis, DNA-DNA Hybridization, and 16S rRNA Gene Sequence Analysis". Journal of Clinical Microbiology 36, nr 4 (1998): 918–25. http://dx.doi.org/10.1128/jcm.36.4.918-925.1998.
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Although Mycobacterium ulcerans, M. marinum, and M. haemophilum are closely related, their exact taxonomic placements have not been determined. We performed gas chromatography of fatty acids and alcohols, as well as DNA-DNA hybridization and 16S rRNA gene sequence analysis, to clarify their relationships to each other and to M. tuberculosis. M. ulcerans and M. marinum were most closely related to one another, and each displayed very strong genetic affinities toM. tuberculosis; they are actually the two mycobacterial species outside the M. tuberculosis complex most closely related to M. tuberculosis. M. haemophilum was more distinct from M. ulcerans and M. marinum, and it appeared to be as related to these two species as to M. tuberculosis. These results are important with regard to the development of diagnostic and epidemiological tools such as species-specific DNA probes and PCR assays for M. ulcerans,M. marinum, and M. haemophilum. In addition, the finding that M. ulcerans and M. marinum are more closely related to M. tuberculosis than are other pathogenic mycobacterial species suggests that they may be evaluated as useful models for studying the pathogenesis of M. tuberculosis. M. marinum may be particularly useful in this regard since strains of this species grow much more rapidly than M. tuberculosis and yet can cause systemic disease in immunocompromised hosts.
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Ho, Vien Q. T., Mark K. Rong, Eva Habjan, Samantha D. Bommer, Thang V. Pham, Sander R. Piersma, Wilbert Bitter, Eelco Ruijter i Alexander Speer. "Dysregulation of Mycobacterium marinum ESX-5 Secretion by Novel 1,2,4-oxadiazoles". Biomolecules 13, nr 2 (21.01.2023): 211. http://dx.doi.org/10.3390/biom13020211.
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The ESX-5 secretion system is essential for the viability and virulence of slow-growing pathogenic mycobacterial species. In this study, we identified a 1,2,4-oxadiazole derivative as a putative effector of the ESX-5 secretion system. We confirmed that this 1,2,4-oxadiazole and several newly synthesized derivatives inhibited the ESX-5-dependent secretion of active lipase LipY by Mycobacterium marinum (M. marinum). Despite reduced lipase activity, we did not observe a defect in LipY secretion itself. Moreover, we found that several other ESX-5 substrates, especially the high molecular-weight PE_PGRS MMAR_5294, were even more abundantly secreted by M. marinum treated with several 1,2,4-oxadiazoles. Analysis of M. marinum grown in the presence of different oxadiazole derivatives revealed that the secretion of LipY and the induction of PE_PGRS secretion were, in fact, two independent phenotypes, as we were able to identify structural features in the compounds that specifically induced only one of these phenotypes. Whereas the three most potent 1,2,4-oxadiazoles displayed only a mild effect on the growth of M. marinum or M. tuberculosis in culture, these compounds significantly reduced bacterial burden in M. marinum-infected zebrafish models. In conclusion, we report a 1,2,4-oxadiazole scaffold that dysregulates ESX-5 protein secretion.
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Sekine, Motoki, Fumiyuki Goto, Kosuke Saito, Shoji Kaneda, Hikaru Yamamoto, Tomoaki Murakami, Takahide Hamano i Kenji Okami. "Fish Tank Granuloma Presenting as a Nasal Cavity Mass". Case Reports in Immunology 2021 (12.01.2021): 1–4. http://dx.doi.org/10.1155/2021/8820720.
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Mycobacterium marinum is a free-living nontuberculous mycobacterium that is widely distributed in freshwater and seawater around the world. Granulomatous skin infection from M. marinum in people who are exposed to fish or aquatic environments is a rare condition known as fish tank granuloma. The granuloma mainly occurs on the skin of the upper limb, in a few cases on the face, and rarely in the nasal cavity. We describe a case of M. marinum infection that presented as a nasal cavity mass. A 57-year-old woman who was receiving infliximab for psoriatic arthritis visited our hospital with a complaint of right nasal obstruction. A granulomatous mass with an irregular surface was found in the anterior part of the right nasal cavity. Tissue biopsy revealed granulation tissue. Since the application of steroid ointment did not reduce the size of the mass, the tumor was resected under local anesthesia, and the base was cauterized. The pathological finding was an inflammatory granuloma with negative Ziehl–Neelsen staining. The granuloma recurred 3 months after resection. The interferon-gamma release assay (IGRA) test was positive, and therefore, a mycobacterial tissue culture test was performed because of suspected nasal tuberculosis, which identified M. marinum. The nasal cavity mass disappeared 2 months after the administration of minocycline, followed by clarithromycin, and subsequent discontinuation of infliximab. M. marinum infection can cause an intranasal mass. IGRA and the mycobacterial tissue culture test are useful for diagnosis. As in this case, the nasal lesion may be excised as an inflammatory nasal granuloma, and therefore, there may be many more “hidden” cases of M. marinum infection. If nasal granulation is present, the possibility of M. marinum infection should be considered.
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van Ingen, Jakko, Rina de Zwaan, Richard Dekhuijzen, Martin Boeree i Dick van Soolingen. "Region of Difference 1 in Nontuberculous Mycobacterium Species Adds a Phylogenetic and Taxonomical Character". Journal of Bacteriology 191, nr 18 (17.07.2009): 5865–67. http://dx.doi.org/10.1128/jb.00683-09.
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ABSTRACT The esat-6 and cfp-10 genes are essential for virulence in Mycobacterium tuberculosis. Among nontuberculous mycobacteria, we found these genes only in M. kansasii, M. szulgai, M. marinum, and M. riyadhense, with unique sequences. This adds a phylogenetic and taxonomical characteristic and may represent a virulence factor for nontuberculous mycobacteria.
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Ramos, José M., Mariana F. García-Sepulcre, Juan C. Rodríguez, Sergio Padilla i Félix Gutiérrez. "Mycobacterium marinum infection complicated by anti-tumour necrosis factor therapy". Journal of Medical Microbiology 59, nr 5 (1.05.2010): 617–21. http://dx.doi.org/10.1099/jmm.0.017277-0.
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Mycobacteria other than tuberculosis infections in patients taking various tumour necrosis factor (TNF)-α inhibitors have been reported in the literature. We describe sporotrichoid spread of Mycobacterium marinum in a man with Crohn's disease treated with infliximab. After starting ethambutol and rifampicin and discontinuing infliximab, a worsening appeared. M. marinum infection may have a potential local spread and systemic dissemination in patients treated with TNF-α inhibitors.
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Sander, Megan A., Judith L. Isaac-Renton i Gregory J. Tyrrell. "Cutaneous Nontuberculous Mycobacterial Infections in Alberta, Canada: An Epidemiologic Study and Review". Journal of Cutaneous Medicine and Surgery 22, nr 5 (17.05.2018): 479–83. http://dx.doi.org/10.1177/1203475418776945.
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Background: Cutaneous infections caused by nontuberculous mycobacteria (NTM) occur infrequently. Nonetheless, the incidence of NTM infections is reported to be increasing. In Canada, cutaneous NTM infections have not been well described. Objectives: A database review from 2006 to 2016 was done to assess species frequency, incidence, and trends of the most common cutaneous NTMs in the province of Alberta, Canada. We also reviewed major diagnostic and epidemiologic aspects of NTM cutaneous infections with a focus on Mycobacterium marinum. Results: A database search identified 244 cases of NTM infections. Mycobacterium avium-intracellulare complex had the highest incidence, causing 64% of cases. Rapid growers ( Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum) caused 23% and M marinum 13%. Information on infection site was available for 117 cases. There was no difference noted in sex distribution; however, differences in age groups between species were noted. Conclusions: The incidence of NTM cutaneous infections in Alberta, Canada, was reported for the first time and the incidence of M marinum was found to be similar to that reported in the worldwide literature. Patients’ age groups were different between species. Knowledge of the unique microbiological features of NTMs and the role of the diagnostic laboratory are important.
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Tuan, Jessica, Anne Spichler-Moffarah i Onyema Ogbuagu. "Mycobacterium marinum: nodular hand lesions after a fishing expedition". BMJ Case Reports 13, nr 12 (grudzień 2020): e238835. http://dx.doi.org/10.1136/bcr-2020-238835.
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Mycobacterium marinum is a slow-growing, acid-fast bacillus in the category of non-tuberculous mycobacteria which most commonly cause skin and soft tissue infections in patients, particularly those with aquatic exposure. Classically, M. marinum skin and soft tissue infections clinically manifest with formation of nodular or sporotrichoid extremity lesions, or deeper space infections such as tenosynovitis and osteomyelitis. Disseminated disease may occur in immunocompromised hosts. M. marinum is a slow-growing organism that is challenging to culture, as it typically requires 5–14 days (yet may take up to several weeks) with low temperatures of approximately 30°C to yield growth. In terms of treatment, further data are needed to elucidate the optimal regimen and duration for M. marinum infections. Combination therapy with clarithromycin and ethambutol is recommended for treatment of skin and soft tissue infections, with addition of rifampicin for deeper space infections. Surgery may be needed in addition to medical management.
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Pagán-Ramos, Eileen, Sharon S. Master, Christopher L. Pritchett, Renate Reimschuessel, Michele Trucksis, Graham S. Timmins i Vojo Deretic. "Molecular and Physiological Effects of Mycobacterial oxyR Inactivation". Journal of Bacteriology 188, nr 7 (1.04.2006): 2674–80. http://dx.doi.org/10.1128/jb.188.7.2674-2680.2006.
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ABSTRACT The majority of slow-growing mycobacteria have a functional oxyR, the central regulator of the bacterial oxidative stress response. In contrast, this gene has been inactivated during the evolution of Mycobacterium tuberculosis. Here we inactivated the oxyR gene in Mycobacterium marinum, an organism used to model M. tuberculosis pathogenesis. Inactivation of oxyR abrogated induction of ahpC, a gene encoding alkylhydroperoxide reductase, normally activated upon peroxide challenge. The absence of oxyR also resulted in increased sensitivity to the front-line antituberculosis drug isoniazid. Inactivation of oxyR in M. marinum did not affect either virulence in a fish infection model or survival in human macrophages. Our findings demonstrate, at the genetic and molecular levels, a direct role for OxyR in ahpC regulation in response to oxidative stress. Our study also indicates that oxyR is not critical for virulence in M. marinum. However, oxyR inactivation confers increased sensitivity to isonicotinic acid hydrazide, suggesting that the natural loss of oxyR in the tubercle bacillus contributes to the unusually high sensitivity of M. tuberculosis to isoniazid.
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Hayes, S. F., i P. L. C. Small. "Evaluation of alternative fixatives/protocols for the ultra-structural preservation of fast and slow growing mycobacteria". Proceedings, annual meeting, Electron Microscopy Society of America 54 (11.08.1996): 814–15. http://dx.doi.org/10.1017/s0424820100166531.
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Various fixation formulas and protocols were examined to determine a routinely optimal fixation of Mycobacterial species in and out of tissues. These were evaluated by TEM and compared to results obtained using freeze substitution methods upon other Mycobacteria such as Mycobacterium aurum CIPT 1210005, M. fortuitum, M. phlei 425, M. kansasii and M. thermoresistible ATCC 19527Samples consisted of two slow growing mycobacterial species, both human pathogens; Mycobacterium tuberculosis, grown in M7H9 broth, and Mycobacterium marinum (1218 R & S variants), grown on M7H10 agar, with the latter also grown in tissue culture, and in guinea pig skin. Fixatives included: (1) glutaraldehyde/parafoimaldahyde/tannic acid in a phosphate/sucrose buffer, (2) paraformaldehyde/polylysine/periodate/glutaraldehyde (PLPG) in phosphate buffer followed by tannic acid and reduced osmium respectively, (3) PLP followed by tannic acid only without osmium, and (4) fixative 84-40 containing carbodiimide, glutaraldehyde and ruthenium red. Protocols varied in the length of time for fixation, types of buffers, solvents and in embedding schedules for Spurr's low viscosity resin.
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Stamm, Luisa M., J. Hiroshi Morisaki, Lian-Yong Gao, Robert L. Jeng, Kent L. McDonald, Robyn Roth, Sunao Takeshita, John Heuser, Matthew D. Welch i Eric J. Brown. "Mycobacterium marinum Escapes from Phagosomes and Is Propelled by Actin-based Motility". Journal of Experimental Medicine 198, nr 9 (3.11.2003): 1361–68. http://dx.doi.org/10.1084/jem.20031072.
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Mycobacteria are responsible for a number of human and animal diseases and are classical intracellular pathogens, living inside macrophages rather than as free-living organisms during infection. Numerous intracellular pathogens, including Listeria monocytogenes, Shigella flexneri, and Rickettsia rickettsii, exploit the host cytoskeleton by using actin-based motility for cell to cell spread during infection. Here we show that Mycobacterium marinum, a natural pathogen of fish and frogs and an occasional pathogen of humans, is capable of actively inducing actin polymerization within macrophages. M. marinum that polymerized actin were free in the cytoplasm and propelled by actin-based motility into adjacent cells. Immunofluorescence demonstrated the presence of host cytoskeletal proteins, including the Arp2/3 complex and vasodilator-stimulated phosphoprotein, throughout the actin tails. In contrast, Wiskott-Aldrich syndrome protein localized exclusively at the actin-polymerizing pole of M. marinum. These findings show that M. marinum can escape into the cytoplasm of infected macrophages, where it can recruit host cell cytoskeletal factors to induce actin polymerization leading to direct cell to cell spread.
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Marmiesse, Magali, Priscille Brodin, Carmen Buchrieser, Christina Gutierrez, Nathalie Simoes, Veronique Vincent, Philippe Glaser, Stewart T. Cole i Roland Brosch. "Macro-array and bioinformatic analyses reveal mycobacterial ‘core’ genes, variation in the ESAT-6 gene family and new phylogenetic markers for the Mycobacterium tuberculosis complex". Microbiology 150, nr 2 (1.02.2004): 483–96. http://dx.doi.org/10.1099/mic.0.26662-0.
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To better understand the biology and the virulence determinants of the two major mycobacterial human pathogens Mycobacterium tuberculosis and Mycobacterium leprae, their genome sequences have been determined recently. In silico comparisons revealed that among the 1439 genes common to both M. tuberculosis and M. leprae, 219 genes code for proteins that show no similarity with proteins from other organisms. Therefore, the latter ‘core’ genes could be specific for mycobacteria or even for the intracellular mycobacterial pathogens. To obtain more information as to whether these genes really were mycobacteria-specific, they were included in a focused macro-array, which also contained genes from previously defined regions of difference (RD) known to be absent from Mycobacterium bovis BCG relative to M. tuberculosis. Hybridization of DNA from 40 strains of the M. tuberculosis complex and in silico comparison of these genes with the near-complete genome sequences from Mycobacterium avium, Mycobacterium marinum and Mycobacterium smegmatis were undertaken to answer this question. The results showed that among the 219 conserved genes, very few were not present in all the strains tested. Some of these missing genes code for proteins of the ESAT-6 family, a group of highly immunogenic small proteins whose presence and number is variable among the genomically highly conserved members of the M. tuberculosis complex. Indeed, the results suggest that, with few exceptions, the ‘core’ genes conserved among M. tuberculosis H37Rv and M. leprae are also highly conserved among other mycobacterial strains, which makes them interesting potential targets for developing new specific anti-mycobacterial drugs. In contrast, the genes from RD regions showed great variability among certain members of the M. tuberculosis complex, and some new specific deletions in Mycobacterium canettii, Mycobacterium microti and seal isolates were identified and further characterized during this study. Together with the distribution of a particular 6 or 7 bp micro-deletion in the gene encoding the polyketide synthase pks15/1, these results confirm and further extend the revised phylogenetic model for the M. tuberculosis complex recently presented.
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Stinear, Timothy P., Grant A. Jenkin, Paul D. R. Johnson i John K. Davies. "Comparative Genetic Analysis of Mycobacterium ulcerans and Mycobacterium marinum Reveals Evidence of Recent Divergence". Journal of Bacteriology 182, nr 22 (15.11.2000): 6322–30. http://dx.doi.org/10.1128/jb.182.22.6322-6330.2000.
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ABSTRACT Previous studies of the 16S rRNA genes from Mycobacterium ulcerans and Mycobacterium marinum have suggested a very close genetic relationship between these species (99.6% identity). However, these organisms are phenotypically distinct and cause diseases with very different pathologies. To investigate this apparent paradox, we compared 3,306 nucleotides from the partial sequences of eight housekeeping and structural genes derived from 18M. ulcerans strains and 22 M. marinumstrains. This analysis confirmed the close genetic relationship inferred from the 16S rRNA data, with nucleotide sequence identity ranging from 98.1 to 99.7%. The multilocus sequence analysis also confirmed previous genotype studies of M. ulceransthat have identified distinct genotypes within a geographical region. Single isolates of both M. ulcerans and M. marinum that were shown by the sequence analysis to be the most closely related were then selected for further study. One- and two-dimensional pulsed-field gel electrophoresis was employed to compare the architecture and size of the genome from each species. Genome sizes of approximately 4.4 and 4.6 Mb were obtained forM. ulcerans and M. marinum, respectively. Significant macrorestriction fragment polymorphism was observed between the species. However, hybridization analysis of DNA cleaved with more frequently cutting enzymes identified significant preservation of the flanking sequence at seven of the eight loci sequenced. The exception was the 16S rRNA locus. Two high-copy-number insertion sequences, IS2404 and IS2606, have recently been reported in M. ulcerans, and significantly, these elements are not present in M. marinum. Hybridization of theAseI restriction fragments from M. ulcerans with IS2404 and IS2606 indicated widespread genome distribution for both of these repeated sequences. Taken together, these data strongly suggest that M. ulcerans has recently diverged from M. marinumby the acquisition and concomitant loss of DNA in a manner analogous to the emergence of M. tuberculosis, where species diversity is being driven mainly by the activity of mobile DNA elements.
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Roth, Andreas, Marga Fischer, Mohamed E. Hamid, Sabine Michalke, Wolfgang Ludwig i Harald Mauch. "Differentiation of Phylogenetically Related Slowly Growing Mycobacteria Based on 16S-23S rRNA Gene Internal Transcribed Spacer Sequences". Journal of Clinical Microbiology 36, nr 1 (1998): 139–47. http://dx.doi.org/10.1128/jcm.36.1.139-147.1998.
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Interspecific polymorphisms of the 16S rRNA gene (rDNA) are widely used for species identification of mycobacteria. 16S rDNA sequences, however, do not vary greatly within a species, and they are either indistinguishable in some species, for example, in Mycobacterium kansasii and M. gastri, or highly similar, for example, in M. malmoense and M. szulgai. We determined 16S-23S rDNA internal transcribed spacer (ITS) sequences of 60 strains in the genus Mycobacterium representing 13 species (M. avium, M. conspicuum, M. gastri, M. genavense, M. kansasii,M. malmoense, M. marinum, M. shimoidei, M. simiae, M. szulgai,M. triplex, M. ulcerans, and M. xenopi). An alignment of these sequences together with additional sequences available in the EMBL database (for M. intracellulare, M. phlei, M. smegmatis, and M. tuberculosis) was established according to primary- and secondary-structure similarities. Comparative sequence analysis applying different treeing methods grouped the strains into species-specific clusters with low sequence divergence between strains belonging to the same species (0 to 2%). The ITS-based tree topology only partially correlated to that based on 16S rDNA, but the main branching orders were preserved, notably, the division of fast-growing from slowly growing mycobacteria, separate branching for M. simiae, M. genavense, and M. triplex, and distinct branches for M. xenopi and M. shimoidei. Comparisons of M. gastri with M. kansasii and M. malmoense with M. szulgairevealed ITS sequence similarities of 93 and 88%, respectively.M. marinum and M. ulcerans possessed identical ITS sequences. Our results show that ITS sequencing represents a supplement to 16S rRNA gene sequences for the differentiation of closely related species. Slowly growing mycobacteria show a high sequence variation in the ITS; this variation has the potential to be used for the development of probes as a rapid approach to mycobacterial identification.
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Smith, Jennifer, Joanna Manoranjan, Miao Pan, Amro Bohsali, Junjie Xu, Jun Liu, Kent L. McDonald, Agnieszka Szyk, Nicole LaRonde-LeBlanc i Lian-Yong Gao. "Evidence for Pore Formation in Host Cell Membranes by ESX-1-Secreted ESAT-6 and Its Role in Mycobacterium marinum Escape from the Vacuole". Infection and Immunity 76, nr 12 (13.10.2008): 5478–87. http://dx.doi.org/10.1128/iai.00614-08.
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ABSTRACT The ESX-1 secretion system plays a critical role in the virulence of M. tuberculosis and M. marinum, but the precise molecular and cellular mechanisms are not clearly defined. Virulent M. marinum is able to escape from the Mycobacterium-containing vacuole (MCV) into the host cell cytosol, polymerize actin, and spread from cell to cell. In this study, we have examined nine M. marinum ESX-1 mutants and the wild type by using fluorescence and electron microscopy detecting MCV membranes and actin polymerization. We conclude that ESX-1 plays an essential role in M. marinum escape from the MCV. We also show that the ESX-1 mutants acquire the ability to polymerize actin after being artificially delivered into the macrophage cytosol by hypotonic shock treatment, indicating that ESX-1 is not directly involved in initiation of actin polymerization. We provide evidence that M. marinum induces membrane pores ∼4.5 nm in diameter, and this activity correlates with ESAT-6 secretion. Importantly, purified ESAT-6, but not the other ESX-1-secreted proteins, is able to cause dose-dependent pore formation in host cell membranes. These results suggest that ESAT-6 secreted by M. marinum ESX-1 could play a direct role in producing pores in MCV membranes, facilitating M. marinum escape from the vacuole and cell-to-cell spread. Our study provides new insight into the mechanism by which ESX-1 secretion and ESAT-6 enhance the virulence of mycobacterial infection.
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Park, Bonggoo, Selvakumar Subbian, Sahar H. El-Etr, Suat L. G. Cirillo i Jeffrey D. Cirillo. "Use of Gene Dosage Effects for a Whole-Genome Screen To Identify Mycobacterium marinum Macrophage Infection Loci". Infection and Immunity 76, nr 7 (28.04.2008): 3100–3115. http://dx.doi.org/10.1128/iai.00015-08.
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ABSTRACT We recently identified two loci, mel1 and mel2, that affect macrophage infection by Mycobacterium marinum. The ability of these loci to confer enhanced infection in trans is presumably due to gene dosage effects since their presence on plasmids increases expression from five- to eightfold. Reasoning that this phenomenon would allow identification of other mycobacterial genes involved in macrophage infection, we conducted a screen of an M. marinum DNA library that provides 2.6-fold coverage of the entire genome for clones that affect macrophage infection. Our preliminary screen identified 76 plasmids that carry loci affecting macrophage infection. We eliminated plasmids that do not confer the expected phenotype when retransformed (70%), that have identical physical maps (5%), or that carry either of the mel1 or mel2 loci (14%) from further consideration. Four loci that confer enhanced infection (mel) and four that confer repressed infection (mrl) of macrophages were identified, and two of each group were chosen for detailed analysis. Saturating transposon mutagenesis was used to identify the loci responsible, and M. marinum mutants were constructed in the genes involved. We expect these genes to provide insight into how mycobacteria parasitize macrophages, an important component of innate immunity.
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Gao, Lian-Yong, Richard Groger, Jeffery S. Cox, Stephen M. Beverley, Elise H. Lawson i Eric J. Brown. "Transposon Mutagenesis of Mycobacterium marinum Identifies a Locus Linking Pigmentation and Intracellular Survival". Infection and Immunity 71, nr 2 (luty 2003): 922–29. http://dx.doi.org/10.1128/iai.71.2.922-929.2003.
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ABSTRACT Pathogenic mycobacteria survive and replicate within host macrophages, but the molecular mechanisms involved in this necessary step in the pathogenesis of infection are not completely understood. Mycobacterium marinum has recently been used as a model for aspects of the pathogenesis of tuberculosis because of its close genetic relationship to Mycobacterium tuberculosis and because of similarities in the pathology and course of infection caused by this organism in its natural hosts, fish and frogs, with tuberculosis in humans. In order to advance the utility of the M. marinum model, we have developed efficient transposon mutagenesis of the organism by using a Drosophila melanogaster mariner-based transposon. To determine the efficiency of transposition, we have analyzed pigmentation mutants from the transposon mutant library. In addition to insertions in four known genes in the pathway of pigment biosynthesis, two insertions in novel genes were identified in our mutant library. One of these is in a putative inhibitor of the carotenoid biosynthesis pathway. The second unexpected insertion is in an intergenic region between two genes homologous to Rv2603c and Rv2604c of M. tuberculosis. In addition to a pigmentation defect, this mutant showed increased susceptibility to singlet oxygen and grew poorly in murine macrophages. Complementation with M. tuberculosis genomic DNA encompassing Rv2603c to Rv2606c corrected the pigmentation and growth defects of the mutant. These data demonstrate the utility of mariner-based transposon mutagenesis of M. marinum and that M. marinum can be used to study the function of M. tuberculosis genes involved in intracellular survival and replication.
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Pagan, Antonio J., Steven Levitte, Russell D. Berg, Laura Hernandez, Joseph Zimmerman, David M. Tobin i Lalita Ramakrishnan. "mTOR deficiency reveals an immunological trade-off in innate resistance to mycobacterial infection in vivo". Journal of Immunology 196, nr 1_Supplement (1.05.2016): 200.6. http://dx.doi.org/10.4049/jimmunol.196.supp.200.6.
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Abstract The Mechanistic Target of Rapamycin (mTOR) has been implicated in myeloid cell development and survival. As adequate myelopoiesis has been recently shown to be a resistance factor in tuberculosis, mTOR deficiency would be expected to increase mycobacterial growth and thus host susceptibility to this disease. In contrast, mTOR inhibition decreases Mycobacterium tuberculosis infection burdens in cultured macrophages, an effect attributed to the triggering of autophagy. Which of these contradictory effects of mTOR deficiency influences infection outcome in vivo is unknown. We have examined the effects of mTOR on mycobacterial infection using the optically transparent and genetically tractable Mycobacterium marinum-zebrafish model of tuberculosis. A forward genetic screen in zebrafish initially identified an mtor mutant as being hypersusceptible to M. marinum, a phenotype that mapped to mTOR complex 1 and was reproduced with rapamycin. However, using very low inoculums typical of human tuberculosis (1–3 mycobacteria) revealed mTOR’s dichotomous role: mTOR-deficient animals were more likely to clear infection early, but those that did not clear the infection progressed rapidly to more severe disease characterized by the death of infected macrophages and subsequent release of mycobacteria into the more growth-permissive extracellular space. Thus, mTOR supports macrophage homeostasis at the expense of a transient enhancement in microbicidal capacity that could reduce the likelihood of mycobacterial colonization but would inevitably thwart long-term immunity.
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Rybniker, Jan, Stefanie Kramme i Pamela L. Small. "Host range of 14 mycobacteriophages in Mycobacterium ulcerans and seven other mycobacteria including Mycobacterium tuberculosis – application for identification and susceptibility testing". Journal of Medical Microbiology 55, nr 1 (1.01.2006): 37–42. http://dx.doi.org/10.1099/jmm.0.46238-0.
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The host range of well-characterized mycobacteriophages, such as D29 and TM4, has been determined, together with that of more recently isolated mycobacteriophages, in Mycobacterium ulcerans, Mycobacterium tuberculosis, Mycobacterium bovis BCG, Mycobacterium avium, Mycobacterium marinum, Mycobacterium scrofulaceum, Mycobacterium fortuitum and Mycobacterium chelonae. Here, a set of virulent phages for M. ulcerans, a pathogen with a dramatic increase of incidence over the last decade, is demonstrated. In this work, a mycobacteriophage replication assay was adapted for the identification and rifampicin-susceptibility testing of M. ulcerans. Mycobacteriophages have generated a number of useful tools and enabled insights into mycobacterial genetics. With regard to the neglected pathogen M. ulcerans, the findings presented in this work allow the application of a large range of phage-based vectors and markers. The potential of phage therapy can now be evaluated for this extracellular pathogen.
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Castillo Almeida, Natalia E., Pooja Gurram i Omar Abu Saleh. "1384. Mycobacterium marinum Infection: 21 Years of Experience at a Tertiary-Care Hospital". Open Forum Infectious Diseases 6, Supplement_2 (październik 2019): S502—S503. http://dx.doi.org/10.1093/ofid/ofz360.1248.
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Abstract Background Mycobacterium marinum is a slow-growing, non-tuberculous mycobacterium responsible for skin and soft-tissue infections (SSTIs), tenosynovitis, and osteomyelitis (OM). We conducted a retrospective study describing the risk, clinical course, and outcome of M. marinum infection. Methods Adult patients with culture-confirmed M. marinum infections were identified from the mycology laboratory at Mayo Clinic, Rochester from January 1998 to December 2018. M. marinum infection was defined as uncomplicated (limited to SST) and complicated (tenosynovitis, OM, or disseminated). Results Forty-six cases of culture-confirmed infection with M. marinum were included (Table 1). Only 16 cases (35%) reported a water exposure and 22 (48%) involved finger and/or hand trauma. The median time to diagnosis was 3.6 months. Most patients (76%) presented with uncomplicated M. marinum infection with skin lesions mainly localized in the upper limb (Table 2). QuantiFERON and PPD were positive in 4 (8%) and 2 (4%) cases, respectively. Granulomatous inflammation and positive special stains were noted in 34 (74%) and 11 (24%) cases, respectively. Cases with complicated M. marinum infection had a longer duration of symptoms and length of treatment (P < 0.05) (Table 3). Prior to diagnosis, 63% of patients received at least one antibiotic for bacterial SSTIs. More than 50% of the patients diagnosed with M. marinum received a one drug regimen and 8% did not initiate therapy. Median treatment duration was 4.4 months. Twenty-six cases (56%) had susceptibilities performed and treatment modifications were made in 10 cases (38%). From the patients that started therapy, 73% completed therapy and 33% were lost to follow up. Cured was achieved in 87% of cases that completed therapy, 2 cases (6%) had a recurrence, and only one patient with active malignancy had a positive blood culture and died. Twelve (44%) and 10 cases (37%) were cured with one and two-drug regimens, respectively. Conclusion Most patients with M. marinum infection present as an uncomplicated infection in the upper limb. Classical exposure was only suspected in a third of the cases. Patients with complicated M. marinum infection had a prolonged duration of symptoms and lengthy treatment. Most patients were successfully treated with a one and two-drug regimen. Disclosures All authors: No reported disclosures.
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Jones, Jefferson J., i Joseph O. Falkinham. "Decolorization of Malachite Green and Crystal Violet by Waterborne Pathogenic Mycobacteria". Antimicrobial Agents and Chemotherapy 47, nr 7 (lipiec 2003): 2323–26. http://dx.doi.org/10.1128/aac.47.7.2323-2326.2003.
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ABSTRACT Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium scrofulaceum, Mycobacterium marinum, and Mycobacterium chelonae tolerate high concentrations of the dyes malachite green and crystal violet. Cells of strains of those species decolorized (reduced) both malachite green and crystal violet. Because decolorized malachite green lacked antimicrobial activity, the resistance of these mycobacteria could be due, in part, to their ability to decolorize the dyes. Small amounts of malachite green and its reduced, decolorized product were detected in the lipid fraction of M. avium strain A5 cells grown in the presence of malachite green, suggesting that a minor component of resistance could be due to sequestering the dyes in the extensive mycobacterial cell surface lipid. The membrane fraction of M. avium strain A5 had at least a fivefold-higher specific decolorization rate than did the crude extract, suggesting that the decolorization activity is membrane associated. The malachite green-decolorizing activity of the membrane fraction of M. avium strain A5 was abolished by either boiling or proteinase exposure, suggesting that the decolorizing activity was due to a protein. Decolorization activity of membrane fractions was stimulated by ferrous ion and inhibited by dinitrophenol and metyrapone.
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Dulanto Chiang, Augusto, Pavel P. Khil, Maura Manion, Irini Sereti, Adrian Zelazny i John P. Dekker. "232. Genomic Evidence for Dissemination of Mycobacterium marinum in an HIV Patient with Multifocal Cutaneous Disease". Open Forum Infectious Diseases 6, Supplement_2 (październik 2019): S133. http://dx.doi.org/10.1093/ofid/ofz360.307.
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Abstract Background Hematogenous dissemination has been proposed to explain multifocal cutaneous disease caused by Mycobacterium marinum in certain patients. Treatment duration for disseminated disease is often months longer than for skin infection alone. However, distinguishing multiple independent inoculation events from dissemination has relied primarily on clinical judgement. Additionally, whether temperature-sensitive non-tuberculous mycobacteria such as M. marinum are indeed capable of invading the vascular space at core body temperature is debated. Here we used whole-genome sequencing (WGS) of serial isolates from a single patient with multifocal cutaneous M. marinum infection to distinguish dissemination of a clonal strain from multiple inoculation events. Methods A 35-year-old male with HIV (CD4 of 66 cells/µL) presented with a two-month history of a non-healing M. marinum wound on his left elbow (isolate MM0). This was followed a month later after initiation of antiretroviral therapy by a second M. marinum lesion on the right heel (MM1) without history of repeat inoculation, and increased swelling and erythema of the wound on the left arm (MM2) consistent with paradoxical immune reconstitution inflammatory syndrome. A PacBio genome was generated for MM0 and short read Illumina genomes were generated for MM1 and MM2. Results All isolates were found to be closely related, with MM1 and MM2 distinguished from MM0 by one and five single-nucleotide variants (SNVs), respectively. Given the substantial genetic heterogeneity among environmental M. marinum strains, such close relatedness of these isolates suggests common origin, and provides strong evidence for dissemination of a clonal strain in this patient. The SNVs included a frameshift mutation in the purT gene, which encodes a formate-dependent phosphoribosylglycinamide formyltransferase involved in de novo purine synthesis, and missense mutations in atsA and the DNA methylase hsdM. All isolates grew at 35°C, compared with the optimal growth temperature of 30°C typically observed for M. marinum, suggesting thermotolerance permissive for dissemination. Conclusion These results demonstrate the potential role of WGS for providing supportive evidence of disseminated infection with M. marinum. Disclosures All authors: No reported disclosures.
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Cosma, Christine L., Kathryn Klein, Rosa Kim, Dana Beery i Lalita Ramakrishnan. "Mycobacterium marinum Erp Is a Virulence Determinant Required for Cell Wall Integrity and Intracellular Survival". Infection and Immunity 74, nr 6 (czerwiec 2006): 3125–33. http://dx.doi.org/10.1128/iai.02061-05.
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ABSTRACT The Mycobacterium tuberculosis exported repetitive protein (Erp) is a virulence determinant required for growth in cultured macrophages and in vivo. To better understand the role of Erp in Mycobacterium pathogenesis, we generated a mutation in the erp homologue of Mycobacterium marinum, a close genetic relative of M. tuberculosis. erp-deficient M. marinum was growth attenuated in cultured macrophage monolayers and during chronic granulomatous infection of leopard frogs, suggesting that Erp function is similarly required for the virulence of both M. tuberculosis and M. marinum. To pinpoint the step in infection at which Erp is required, we utilized a zebrafish embryo infection model that allows M. marinum infections to be visualized in real-time, comparing the erp-deficient strain to a ΔRD1 mutant whose stage of attenuation was previously characterized in zebrafish embryos. A detailed microscopic examination of infected embryos revealed that bacteria lacking Erp were compromised very early in infection, failing to grow and/or survive upon phagocytosis by host macrophages. In contrast, ΔRD1 mutant bacteria grow normally in macrophages but fail to induce host macrophage aggregation and subsequent cell-to-cell spread. Consistent with these in vivo findings, erp-deficient but not RD1-deficient bacteria exhibited permeability defects in vitro, which may be responsible for their specific failure to survive in host macrophages.
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Subbian, Selvakumar, Parmod K. Mehta, Suat L. G. Cirillo, Luiz E. Bermudez i Jeffrey D. Cirillo. "A Mycobacterium marinum mel2 Mutant Is Defective for Growth in Macrophages That Produce Reactive Oxygen and Reactive Nitrogen Species". Infection and Immunity 75, nr 1 (9.10.2006): 127–34. http://dx.doi.org/10.1128/iai.01000-06.
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ABSTRACT Macrophages produce reactive oxygen species (ROS) and reactive nitrogen species (RNS) in response to bacterial infections. Mycobacteria are relatively resistant to ROS, but RNS inhibit growth of, and possibly even kill, mycobacteria in activated macrophages. We recently constructed a Mycobacterium marinum mel2 locus mutant, which is known to affect macrophage infection. We found previously that the mel2 locus confers resistance to ROS and RNS in laboratory medium, suggesting that this locus might play a similar role during growth in macrophages. Since J774A.1 murine macrophages produce high levels of ROS and RNS upon activation with gamma interferon (IFN-γ), we examined the effects of IFN-γ on ROS and RNS production by these cells as well as the effects on growth of M. marinum in these cells. We found that an M. marinum mutant with mutation of the first gene in the mel2 locus, melF, is defective for growth in IFN-γ-plus-lipopolysaccharide-treated J774A.1 cells and that this defect is abrogated by the presence of either inhibitors of nitric oxide synthase or ROS scavengers. Furthermore, the M. marinum melF mutant displays a defect at late stages in the mouse footpad model of infection. These phenotypic characteristics could be complemented fully by the entire mel2 locus but only partially by the presence of melF alone, supporting data suggesting that this insertion mutation has polar effects on downstream genes in the mel2 locus. These observations demonstrate that the M. marinum mel2 locus plays a role in resistance to ROS and RNS produced by activated macrophages.
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Swaim, Laura E., Lynn E. Connolly, Hannah E. Volkman, Olivier Humbert, Donald E. Born i Lalita Ramakrishnan. "Mycobacterium marinum Infection of Adult Zebrafish Causes Caseating Granulomatous Tuberculosis and Is Moderated by Adaptive Immunity". Infection and Immunity 74, nr 11 (listopad 2006): 6108–17. http://dx.doi.org/10.1128/iai.00887-06.
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ABSTRACT The zebrafish, a genetically tractable model vertebrate, is naturally susceptible to tuberculosis caused by Mycobacterium marinum, a close genetic relative of the causative agent of human tuberculosis, Mycobacterium tuberculosis. We previously developed a zebrafish embryo-M. marinum infection model to study host-pathogen interactions in the context of innate immunity. Here, we have constructed a flowthrough fish facility for the large-scale longitudinal study of M. marinum-induced tuberculosis in adult zebrafish where both innate and adaptive immunity are operant. We find that zebrafish are exquisitely susceptible to M. marinum strain M. Intraperitoneal injection of five organisms produces persistent granulomatous tuberculosis, while the injection of ∼9,000 organisms leads to acute, fulminant disease. Bacterial burden, extent of disease, pathology, and host mortality progress in a time- and dose-dependent fashion. Zebrafish tuberculous granulomas undergo caseous necrosis, similar to human tuberculous granulomas. In contrast to mammalian tuberculous granulomas, zebrafish lesions contain few lymphocytes, calling into question the role of adaptive immunity in fish tuberculosis. However, like rag1 mutant mice infected with M. tuberculosis, we find that rag1 mutant zebrafish are hypersusceptible to M. marinum infection, demonstrating that the control of fish tuberculosis is dependent on adaptive immunity. We confirm the previous finding that M. marinum ΔRD1 mutants are attenuated in adult zebrafish and extend this finding to show that ΔRD1 predominantly produces nonnecrotizing, loose macrophage aggregates. This observation suggests that the macrophage aggregation defect associated with ΔRD1 attenuation in zebrafish embryos is ongoing during adult infection.
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van der Sar, Astrid M., Abdallah M. Abdallah, Marion Sparrius, Erik Reinders, Christina M. J. E. Vandenbroucke-Grauls i Wilbert Bitter. "Mycobacterium marinum Strains Can Be Divided into Two Distinct Types Based on Genetic Diversity and Virulence". Infection and Immunity 72, nr 11 (listopad 2004): 6306–12. http://dx.doi.org/10.1128/iai.72.11.6306-6312.2004.
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ABSTRACT Mycobacterium marinum causes a systemic tuberculosis-like disease in a large number of poikilothermic animals and is used as a model for mycobacterial pathogenesis. In the present study, we infected zebra fish (Danio rerio) with different strains of M. marinum to determine the variation in pathogenicity. Depending on the M. marinum isolate, the fish developed an acute or chronic disease. Acute disease was characterized by uncontrolled growth of the pathogen and death of all animals within 16 days, whereas chronic disease was characterized by granuloma formation in different organs and survival of the animals for at least 4 to 8 weeks. Genetic analysis of the isolates by amplified fragment length polymorphism showed that M. marinum strains could be divided in two clusters. Cluster I contained predominantly strains isolated from humans with fish tank granuloma, whereas the majority of the cluster II strains were isolated from poikilothermic species. Acute disease progression was noted only with strains belonging to cluster I, whereas all chronic-disease-causing isolates belonged to cluster II. This difference in virulence was also observed in vitro: cluster I isolate Mma20 was able to infect and survive more efficiently in the human macrophage THP-1 and the carp leukocyte CLC cell lines than was the cluster II isolate Mma11. We conclude that strain characteristics play an important role in the pathogenicity of M. marinum. In addition, the correlation between genetic variation and host origin suggests that cluster I isolates are more pathogenic for humans.
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Whipps, Christopher M., W. Ray Butler, Fazel Pourahmad, Virginia G. Watral i Michael L. Kent. "Molecular systematics support the revival of Mycobacterium salmoniphilum (ex Ross 1960) sp. nov., nom. rev., a species closely related to Mycobacterium chelonae". International Journal of Systematic and Evolutionary Microbiology 57, nr 11 (1.11.2007): 2525–31. http://dx.doi.org/10.1099/ijs.0.64841-0.
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Mycobacterial infections in fish are usually attributed to strains of Mycobacterium marinum, Mycobacterium chelonae and Mycobacterium fortuitum. Bacteria identified as M. chelonae have been isolated numerous times from salmonid fishes. Recently, this bacterium has been associated with salmon mortalities in the aquaculture industry. An M. chelonae-like species from salmon, ‘Mycobacterium salmoniphilum’, was described in 1960. However, the species name lost standing in nomenclature when it was omitted from the 1980 Approved Lists of Bacterial Names because the species could not be distinguished with confidence from M. fortuitum. In the 1980s, mycobacteria isolated from salmon were characterized as a distinct subspecies, ‘Mycobacterium chelonae subsp. piscarium’. Again, the uncertainty of the validity of the species resulted in the subsequent withdrawal of the name. Since then, most studies have considered isolates from salmon to be M. chelonae. Nucleotide sequence analysis of the small-subunit rRNA, hsp65 and rpoB genes was used to examine the taxonomic relatedness of type cultures and authentic isolates in our culture collection available from earlier studies. The M. chelonae-like strains from salmon were phylogenetically distinct from other Mycobacterium strains and members of the M. chelonae complex. Moreover, the cell-wall-bound mycolic acids were not representative of known mycolate patterns for M. chelonae-complex organisms. These results supported the status of the species as a separate taxon and effect the valid publication of the name ‘M. salmoniphilum’ as Mycobacterium salmoniphilum (ex Ross 1960) sp. nov., nom. rev., with the type strain SCT (=ATCC 13578T =DSM 43276T).
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Saito, Hajime, Tomotada Iwamoto, Kiyofumi Ohkusu, Yoshihito Otsuka, Yasushi Akiyama, Shigeki Sato, Osamu Taguchi i in. "Mycobacterium shinjukuense sp. nov., a slowly growing, non-chromogenic species isolated from human clinical specimens". International Journal of Systematic and Evolutionary Microbiology 61, nr 8 (1.08.2011): 1927–32. http://dx.doi.org/10.1099/ijs.0.025478-0.
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Seven isolates of a slowly growing, non-chromogenic Mycobacterium species were obtained from sputum and bronchial lavage fluid samples from elderly patients in different regions of Japan. These isolates were distinguished from related non-tuberculous species by colony morphology, positive results for Tween hydrolysis, catalase at 68 °C, nitrate reductase and pyrazinamidase and negative results for semi-quantitative catalase, urease and arylsulfatase. The mycolic acid pattern obtained by HPLC revealed a single cluster of late-eluting mycolic acids similar to but different from those of Mycobacterium malmoense ATCC 29571T. The 16S rRNA gene, 16S–23S internal transcribed spacer (ITS), rpoB and hsp65 sequences were unique in comparison with those of other mycobacteria. Comparison of 16S rRNA gene sequences showed that the isolates were most closely related to Mycobacterium tuberculosis H37RvT (21 base differences in 1508 bp; 98.6 % 16S rRNA gene sequence similarity). A representative strain, GTC 2738T, showed 91.9 % rpoB sequence similarity with Mycobacterium marinum strain M, 95 % hsp65 sequence similarity with Mycobacterium kansasii CIP 104589T and 81.1 % 16S–23S ITS sequence similarity with Mycobacterium gordonae ATCC 14470T. Phylogenetic analysis of concatenated sequences of the 16S rRNA, rpoB and hsp65 genes showed that strain GTC 2738T was located on a distinct clade adjacent to M. tuberculosis, M. ulcerans and M. marinum, with bootstrap values of 81 %. DNA–DNA hybridization demonstrated less than 70 % reassociation with type strains of genetically related species and supported the novel species status of the isolates. On the basis of this evidence, a novel species with the name Mycobacterium shinjukuense sp. nov. is proposed. The type strain, isolated from a sputum sample, is strain GTC 2738T( = JCM 14233T = CCUG 53584T).
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Rämet, Mika, Kaisa Oksanen, Sanna-Kaisa Harjula, Nicholas Halfpenny, Vuoksio Milka, Elina Pajula i Mataleena Parikka. "A zebrafish model to develop DNA-based vaccines - identification of cdh as a protective antigen against mycobacterial disease (166.19)". Journal of Immunology 188, nr 1_Supplement (1.05.2012): 166.19. http://dx.doi.org/10.4049/jimmunol.188.supp.166.19.
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Abstract Mycobacterium tuberculosis, the causative agent of human tuberculosis, is an intracellular pathogen killing nearly two million people annually. The current live vaccine is controversial and thus novel preventive approaches are needed. DNA vaccines represent an alternative for immunizing against tuberculosis. As a vertebrate model organism with a fully developed immune system, zebrafish (Danio rerio) presents itself as an attractive and ethical option for screening novel vaccine antigens. Here we show that antigens can be expressed in the adult zebrafish as DNA-based vaccines. Furthermore, introduction of DNA plasmids expressing a combination of three previously characterized mycobacterial antigens (Ag85B, ESAT-6, CFP-10) was protective against M. marinum challenge in adult zebrafish. Using a low-dose intra peritoneal infection with 19-28 bacteria, both the number of granulomas and the amount of affected organs were reduced. Likewise, using a lethal infection dose of 20,000 cfu, vaccination significantly reduced both mortality and bacterial counts. In addition, a putative diacylglycerol pyrophosphatase cdh was protective against lethal M. marinum infection with 25, 000 cfu decreasing mortality by more than 50% compared to controls. In summary, DNA-based vaccination protects adult zebrafish against experimental Mycobacterium marinum infection and cdh is a promising novel protective antigen in this model.
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Sánchez-Chardi, A., C. Brambilla, E. Julián i M. Luquin. "Cording, a Virulence-related Characteristic of Mycobacteria, Analysis Using SEM". Microscopy and Microanalysis 18, S5 (sierpień 2012): 21–22. http://dx.doi.org/10.1017/s1431927612012767.
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Cord formation in Mycobacterium tuberculosis has been traditionally related to virulence since avirulent M. tuberculosis strains do not form cords. These structures consist of bacilli aligned in parallel, end to end, and side to side, along the long axis of the cord. However, similar structures were recently found in non-pathogenic and in opportunistic Mycobacterium species such as M. abscessus, M. chubuense, M. gilvum, M. haemophilum, M. marinum, M. obuense, M. parafortuitum, and M. vaccae. Although the visualization of cords has been traditionally achieved using Ziehl-Neelsen staining, the resolution of light microscopy does not allow to distinguish among cords, pseudocords, clumps or loose aggregates. Nevertheless, the observation of these formations at high resolution is crucial for two essential applications. Firstly, to identify the unknown mycobacterial components responsible for cording formation, an important step to understand virulence. Secondly, to demonstrate that cording is not specific of M. tuberculosis, since many clinical mycobacteriology laboratories base the tuberculosis diagnostic on the observation of cording morphology, and may mistakenly identify non-tuberculous mycobacteria as M. tuberculosis. Thus, patients would be exposed to an ineffective drug regimen with many adverse side effects. Here, we focused on sample treatment in order to certainly observe cords by using scanning electron microscopy (SEM).
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Stinear, Timothy P., Melinda J. Pryor, Jessica L. Porter i Stewart T. Cole. "Functional analysis and annotation of the virulence plasmid pMUM001 from Mycobacterium ulcerans". Microbiology 151, nr 3 (1.03.2005): 683–92. http://dx.doi.org/10.1099/mic.0.27674-0.
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The presence of a 174 kb plasmid called pMUM001 in Mycobacterium ulcerans, the first example of a mycobacterial plasmid encoding a virulence determinant, was recently reported. Over half of pMUM001 is devoted to six genes, three of which encode giant polyketide synthases (PKS) that produce mycolactone, an unusual cytotoxic lipid produced by M. ulcerans. In this present study the remaining 75 non-PKS-associated protein-coding sequences (CDS) are analysed and it is shown that pMUM001 is a low-copy-number element with a functional ori that supports replication in Mycobacterium marinum but not in the fast-growing mycobacteria Mycobacterium smegmatis and Mycobacterium fortuitum. Sequence analyses revealed a highly mosaic plasmid gene structure that is reminiscent of other large plasmids. Insertion sequences (IS) and fragments of IS, some previously unreported, are interspersed among functional gene clusters, such as those genes involved in plasmid replication, the synthesis of mycolactone, and a potential phosphorelay signal transduction system. Among the IS present on pMUM001 were multiple copies of the high-copy-number M. ulcerans elements IS2404 and IS2606. No plasmid transfer systems were identified, suggesting that trans-acting factors are required for mobilization. The results presented here provide important insights into this unusual virulence plasmid from an emerging but neglected human pathogen.
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Gauthier, DT, AN Haines i WK Vogelbein. "Elevated temperature inhibits Mycobacterium shottsii infection and Mycobacterium pseudoshottsii disease in striped bass Morone saxatilis". Diseases of Aquatic Organisms 144 (6.05.2021): 159–74. http://dx.doi.org/10.3354/dao03584.
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Mycobacteriosis occurs with high prevalence in the wild striped bass Morone saxatilis of Chesapeake Bay, USA. Etiologic agents of mycobacteriosis in this system are dominated by Mycobacterium pseudoshottsii and Mycobacterium shottsii, both members of the M. ulcerans/M. marinum clade of mycobacteria. Striped bass occupying Chesapeake Bay during summer months where water temperatures regularly approach and occasionally exceed 30°C are thought to be near their thermal maximum, a condition hypothesized to drive high levels of disease and increased natural mortality due to temperature stress. M. shottsii and M. pseudoshottsii, however, do not grow or grow inconsistently at 30°C on artificial medium, potentially countering this hypothesis. In this work, we examine the effects of temperature (20, 25, and 30°C) on progression of experimental infections with M. shottsii and M. pseudoshottsii in striped bass. Rather than exacerbation of disease, increasing temperature resulted in attenuated bacterial density increase in the spleen and reduced pathology in the spleen and mesenteries of M. pseudoshottsii infected fish, and reduced bacterial densities in the spleen of M. shottsii infected fish. These findings indicate that M. pseudoshottsii and M. shottsii infections in Chesapeake Bay striped bass may be limited by the thermal tolerance of these mycobacteria, and that maximal disease progression may in fact occur at lower water temperatures.
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Moestrup, Pernille Grand, Maiken Stilling, Christian Morberg Wejse i Victor Naestholt Dahl. "Mycobacterium marinum: A Challenging Cause of Protracted Tenosynovitis". Antibiotics 12, nr 3 (22.03.2023): 629. http://dx.doi.org/10.3390/antibiotics12030629.
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Mycobacterium marinum infections are rare, and they can be difficult to diagnose and treat. This may lead to further spread of the infection and complications, such as tenosynovitis, pyomyositis, and osteomyelitis. A 40-year-old previously healthy man presented with tenosynovitis of the extensor tendons on the second phalanx of his right hand. He was initially treated with steroid injections without any effect. Followingly, ulceration and an abscess developed on the dorsal site of the hand. At this point, it came to the physician’s knowledge that the patient had been cleaning an aquarium before onset of symptoms. After progression to massive tenosynovitis, the patient was admitted and underwent multiple surgical debridements. Briefly, after the first surgery, an interferon-γ release assay was positive, and treatment for M. marinum with rifampicin and azithromycin was initiated after eight months of symptoms. Later, a surgical biopsy showed acid-fast bacilli, and a polymerase chain reaction confirmed the diagnosis of M. marinum. In this case story, we highlight the difficulties of diagnosing and managing this complicated infection, describe the considerable morbidity associated with it, and suggest that local tissue concentrations could be useful to improve clinical outcomes, as these concentrations are potentially suboptimal.
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K�ser, Michael, Julia Hauser, Pamela Small i Gerd Pluschke. "Large Sequence Polymorphisms Unveil the Phylogenetic Relationship of Environmental and Pathogenic Mycobacteria Related to Mycobacterium ulcerans". Applied and Environmental Microbiology 75, nr 17 (10.07.2009): 5667–75. http://dx.doi.org/10.1128/aem.00446-09.
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ABSTRACT Mycolactone is an immunosuppressive cytotoxin responsible for the clinical manifestation of Buruli ulcer in humans. It was believed to be confined to its etiologic agent, Mycobacterium ulcerans. However, the identification of other mycolactone-producing mycobacteria (MPMs) in other species, including Mycobacterium marinum, indicated a more complex taxonomic relationship. This highlighted the need for research on the biology, evolution, and distribution of such emerging and potentially infectious strains. The reliable genetic fingerprinting analyses presented here aim at both the unraveling of phylogenetic relatedness and of dispersal between environmental and pathogenic mycolactone producers and the identification of genetic prerequisites that enable lateral gene transfer of such plasmids. This will allow for the identification of environmental reservoirs of virulence plasmids that encode enzymes required for the synthesis of mycolactone. Based on dynamic chromosomal loci identified earlier in M. ulcerans, we characterized large sequence polymorphisms for the phylogenetic analysis of MPMs. Here, we identify new insertional-deletional events and single-nucleotide polymorphisms that confirm and redefine earlier strain differentiation markers. These results support other data showing that all MPMs share a common ancestry. In addition, we found unique genetic features specific for M. marinum strain M, the genome sequence strain which is used widely in research.
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Piddington, Debra L., Ali Kashkouli i Nancy A. Buchmeier. "Growth of Mycobacterium tuberculosis in a Defined Medium Is Very Restricted by Acid pH and Mg2+ Levels". Infection and Immunity 68, nr 8 (1.08.2000): 4518–22. http://dx.doi.org/10.1128/iai.68.8.4518-4522.2000.
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ABSTRACT Mycobacterium tuberculosis grows within the phagocytic vacuoles of macrophages, where it encounters a moderately acidic and possibly nutrient-restricted environment. Other mycobacterial species encounter acidic conditions in soil and aquatic environments. We have evaluated the influence of pH and divalent cation levels on the growth of M. tuberculosis and seven other mycobacterial species. In a defined medium, the growth of M. tuberculosis was very restricted by acidic pH. Higher levels of Mg2+ were required for growth of M. tuberculosis in mildly acidic media (pH 6.0 to 6.5) compared to pH 7.0 medium. The divalent cations Ca2+, Zn2+, or Mn2+ could not replace Mg2+ during growth at pH 6.25, but Ca2+could at least partially substitute for Mg2+ during growth at pH 7.0. Among eight species of mycobacteria tested, there was a diversity of growth rates in media with acidic pH and low Mg2+ levels. M. tuberculosis was the most restricted in growth at pH 6.0, and all of this growth required elevated levels of Mg2+. M. kansasii andM. smegmatis also grew very poorly in acidic media with limiting Mg2+. M. fortuitum, M. marinum, M. scrofulaceum, M. avium, andM. chelonae grew at pH 6.0 in an unrestricted manner. These results demonstrate that M. tuberculosis is unique among the mycobacteria in its extreme sensitivity to acid and indicate thatM. tuberculosis must acquire sufficient Mg2+ in order to grow in a mildly acidic environment such as within the phagosome of macrophages.