Journal articles on the topic 'Plasmid resistance'
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1
Ling, J. M., P. C. Shaw, K. M. Kam, A. F. Cheng, and G. L. French. "Molecular studies of plasmids of multiply-resistantShigellaspp. in Hong Kong." Epidemiology and Infection 110, no. 3 (June 1993): 437–46. http://dx.doi.org/10.1017/s095026880005086x.
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SUMMARYOne hundred and twoShigellaspp. isolated in two hospitals in Hong Kong were analysed for antibiotic resistances, resistance plasmids and plasmid profiles. Three quarters of the isolates wereS.flexneri. All isolates harboured plasmids, up to a maximum of ten within one strain. Plasmids of 220 kb encoding resistances to tetracycline, chloramphenicol and sulphonamide and probably also associated with invasivenes in the Sereny test were found in 80 strains and were transferable in 18% of cases. Resistance plasmids of 92 and 99 kb were found in 27 and 15 strains respectively and encoded resistances to ampicillin, tetracycline, chloramphenicol, kanamycin, sulphonamide, trimethoprim, cotrimoxazole and gentamicin; these plasmids were usually transferable. Four plasmids of 3·9, 2·8, 2·2 and 1·8 kb were commonly found inS. flexneristrains, but were rare in other species. In contrast, there was no predominant plasmid profile inS. sonnei. S. flexneriis endemic in Hong Kong and these plasmid studies suggest that the strains in circulation are derived from only a few clones.
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Jalasvuori, Matti, Ville-Petri Friman, Anne Nieminen, Jaana K. H. Bamford, and Angus Buckling. "Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids." Biology Letters 7, no. 6 (June 2011): 902–5. http://dx.doi.org/10.1098/rsbl.2011.0384.
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Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple antibiotic-resistance genes containing plasmids are stably maintained in both Escherichia coli and Salmonella enterica in the absence of phages, while plasmid-dependent phage PRD1 causes a dramatic reduction in the frequency of antibiotic-resistant bacteria. The loss of antibiotic resistance in cells initially harbouring RP4 plasmid was shown to result from evolution of phage resistance where bacterial cells expelled their plasmid (and hence the suitable receptor for phages). Phages also selected for a low frequency of plasmid-containing, phage-resistant bacteria, presumably as a result of modification of the plasmid-encoded receptor. However, these double-resistant mutants had a growth cost compared with phage-resistant but antibiotic-susceptible mutants and were unable to conjugate. These results suggest that bacteriophages could play a significant role in restricting the spread of plasmid-encoded antibiotic resistance.
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Erac, Bayri, Fethiye Ferda Yilmaz, Ismail Ozturk, Sabire Sohret Aydemir, and Mine Hosgor-Limoncu. "Analyses of Plasmids Harbouring Quinolone Resistance Determinants in Enterobacteriaceae Members." Polish Journal of Microbiology 66, no. 4 (December 4, 2017): 529–32. http://dx.doi.org/10.5604/01.3001.0010.7084.
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The aim of this study was to explore the plasmid characteristics of eight clinical Enterobacteriaceae strains containing extended broad spectrum beta-lactamases and plasmid-mediated quinolone resistance. Plasmids were transferred by conjugation or transformation and resistance determinants were investigated by PCR. We showed that at least one plasmid harbouring qnrB or qnrS determinant was transferred by conjugation in five isolates. QepA determinant was confirmed to be on a non-conjugative plasmid. We found at least one beta-lactamase gene in seven of the eight clinical isolates having plasmid-mediated quinolone resistance, which indicated that these two resistance determinants were mostly on the same conjugative plasmids.
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Hernández-Mendoza, Armando, Rosalba Salgado-Morales, Abimael Morán-Vázquez, David López-Torres, Blanca Inés García-Gómez, and Edgar Dantán-González. "Molecular Characterization of pBOq-IncQ and pBOq-95LK Plasmids of Escherichia coli BOq 01, a New Isolated Strain from Poultry Farming, Involved in Antibiotic Resistance." Microorganisms 10, no. 8 (July 26, 2022): 1509. http://dx.doi.org/10.3390/microorganisms10081509.
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The increase in antimicrobial resistance has raised questions about how to use these drugs safely, especially in veterinary medicine, animal nutrition, and agriculture. Escherichia coli is an important human and animal pathogen that frequently contains plasmids carrying antibiotic resistance genes. Extra chromosomal elements are required for various functions or conditions in microorganisms. Several phage-like plasmids have been identified, which are important in antibiotic resistance. In this work, the molecular characterization of the pBOq-IncQ (4.5 kb) and pBOq-95LK (95 kb) plasmids found in the E. coli strain BOq 01, a multidrug resistant bacteria isolated from a poultry farm, are considered. Plasmid pBOq-IncQ belongs to the incQ incompatibility plasmid family and is involved in sulfonamide resistance. Plasmid pBOq-95LK is a lytic phage-like plasmid that is involved in the lysis of the E. coli BOq 01 strain and carries a bleomycin resistance gene and a strain cured of this plasmid shows bleomycin sensitivity. Induction of the lytic cycle indicates that this phage-like plasmid is an active phage. This type of plasmid has been reported to acquire genes such as mcr-1, which codes for colistin resistance and bacterial persistence and is a significant public health threat. A genome comparison, a pangenomic and phylogenomic analysis with other phage-like plasmids reported in the literature were performed to understand better the evolution of this kind of plasmid in bacteria and its potential importance in antibiotic resistance.
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Hoshino, Takayuki, Takayuki Ikeda, Hiroyuki Narushima, and Noboru Tomizuka. "Isolation and characterization of antibiotic-resistance plasmids in thermophilic bacilli." Canadian Journal of Microbiology 31, no. 4 (April 1, 1985): 339–45. http://dx.doi.org/10.1139/m85-065.
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Four antibiotic-resistance plasmids isolated from thermophilic bacilli were characterized in detail. Three tetracycline-resistance (Tcr) plasmids were designated as pTHT9 (7.7 kilobases (kb)), pTHT15 (4.5 kb) and pTHT22 (8.4 kb). From the results of restriction endonuclease analysis and the subsequent Southern hybridization, these were found to possess extensive genetic homology in the regions that include the replication origin and the Tcr gene. Detailed restriction maps of the smallest Tcr plasmid pTHT15 and a kanamycin-resistance (Kmr) plasmid pTHN1 (4.8 kb) were constructed. The positions of antibiotic-resistance loci and regions essential for plasmid replication were determined by cloning plasmid fragments in Bacillus subtilis. These four plasmids were found to replicate and express the resistance genes stably in both B. subtilis and B. stearothermophilus.
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Bottery, Michael J., A. Jamie Wood, and Michael A. Brockhurst. "Selective Conditions for a Multidrug Resistance Plasmid Depend on the Sociality of Antibiotic Resistance." Antimicrobial Agents and Chemotherapy 60, no. 4 (January 19, 2016): 2524–27. http://dx.doi.org/10.1128/aac.02441-15.
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ABSTRACTMultidrug resistance (MDR) plasmids frequently carry antibiotic resistance genes conferring qualitatively different mechanisms of resistance. We show here that the antibiotic concentrations selecting for the RK2 plasmid inEscherichia colidepend upon the sociality of the drug resistance: the selection for selfish drug resistance (efflux pump) occurred at very low drug concentrations, just 1.3% of the MIC of the plasmid-free antibiotic-sensitive strain, whereas selection for cooperative drug resistance (modifying enzyme) occurred at drug concentrations exceeding the MIC of the plasmid-free strain.
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Fricke, W. Florian, Timothy J. Welch, Patrick F. McDermott, Mark K. Mammel, J. Eugene LeClerc, David G. White, Thomas A. Cebula, and Jacques Ravel. "Comparative Genomics of the IncA/C Multidrug Resistance Plasmid Family." Journal of Bacteriology 191, no. 15 (May 29, 2009): 4750–57. http://dx.doi.org/10.1128/jb.00189-09.
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ABSTRACT Multidrug resistance (MDR) plasmids belonging to the IncA/C plasmid family are widely distributed among Salmonella and other enterobacterial isolates from agricultural sources and have, at least once, also been identified in a drug-resistant Yersinia pestis isolate (IP275) from Madagascar. Here, we present the complete plasmid sequences of the IncA/C reference plasmid pRA1 (143,963 bp), isolated in 1971 from the fish pathogen Aeromonas hydrophila, and of the cryptic IncA/C plasmid pRAx (49,763 bp), isolated from Escherichia coli transconjugant D7-3, which was obtained through pRA1 transfer in 1980. Using comparative sequence analysis of pRA1 and pRAx with recent members of the IncA/C plasmid family, we show that both plasmids provide novel insights into the evolution of the IncA/C MDR plasmid family and the minimal machinery necessary for stable IncA/C plasmid maintenance. Our results indicate that recent members of the IncA/C plasmid family evolved from a common ancestor, similar in composition to pRA1, through stepwise integration of horizontally acquired resistance gene arrays into a conserved plasmid backbone. Phylogenetic comparisons predict type IV secretion-like conjugative transfer operons encoded on the shared plasmid backbones to be closely related to a group of integrating conjugative elements, which use conjugative transfer for horizontal propagation but stably integrate into the host chromosome during vegetative growth. A hipAB toxin-antitoxin gene cluster found on pRA1, which in Escherichia coli is involved in the formation of persister cell subpopulations, suggests persistence as an early broad-spectrum antimicrobial resistance mechanism in the evolution of IncA/C resistance plasmids.
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Lim, Suk-Kyung, Koichi Tanimoto, Haruyoshi Tomita, and Yasuyoshi Ike. "Pheromone-Responsive Conjugative Vancomycin Resistance Plasmids in Enterococcus faecalis Isolates from Humans and Chicken Feces." Applied and Environmental Microbiology 72, no. 10 (October 2006): 6544–53. http://dx.doi.org/10.1128/aem.00749-06.
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ABSTRACT The drug resistances and plasmid contents of a total of 85 vancomycin-resistant enterococcus (VRE) strains that had been isolated in Korea were examined. Fifty-four of the strains originated from samples of chicken feces, and 31 were isolated from hospital patients in Korea. Enterococcus faecalis KV1 and KV2, which had been isolated from a patient and a sample of chicken feces, respectively, were found to carry the plasmids pSL1 and pSL2, respectively. The plasmids transferred resistances to vancomycin, gentamicin, kanamycin, streptomycin, and erythromycin to E. faecalis strains at a high frequency of about 10−3 per donor cell during 4 hours of broth mating. E. faecalis strains containing each of the pSL plasmids formed clumps after 2 hours of incubation in broth containing E. faecalis FA2-2 culture filtrate (i.e., the E. faecalis sex pheromone), and the plasmid subsequently transferred to the recipient strain in a 10-min short mating in broth, indicating that the plasmids are responsive to E. faecalis pheromones. The pSL plasmids did not respond to any of synthetic pheromones for the previously characterized plasmids. The pheromone specific for pSL plasmids has been designated cSL1. Southern hybridization analysis showed that specific FspI fragments from each of the pSL plasmids hybridized with the aggregation substance gene (asa1) of the pheromone-responsive plasmid pAD1, indicating that the plasmids had a gene homologous to asa1. The restriction maps of the plasmids were identical, and the size of the plasmids was estimated to be 128.1 kb. The plasmids carried five drug resistance determinants for vanA, ermB, aph(3′), aph(6′), and aac(6′)/aph(2′), which encode resistance to vancomycin, erythromycin, kanamycin, streptomycin, and gentamicin/kanamycin, respectively. Nucleotide sequence analyses of the drug resistance determinants and their flanking regions are described in this report. The results described provide evidence for the exchange of genetic information between human and animal (chicken) VRE reservoirs and suggest the potential for horizontal transmission of multiple drug resistance, including vancomycin resistance, between farm animals and humans via a pheromone-responsive conjugative plasmid.
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Giles, Janice S., Harry Hariharan, and Susan B. Heaney. "The plasmid profiles of fish pathogenic isolates of Aeromonas salmomcida, Vibrio anguillarum, and Vibrio ordalii from the Atlantic and Pacific coasts of Canada." Canadian Journal of Microbiology 41, no. 3 (March 1, 1995): 209–16. http://dx.doi.org/10.1139/m95-029.
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The plasmid profiles of oxytetracycline- and streptomycin-resistant isolates of Aeromonas salmonicida, Vibrio anguillarum, and Vibrio ordalii were examined by agarose gel electrophoresis. Bacterial isolates were from disease outbreaks in fish on the Atlantic and Pacific coasts. Resistant isolates were examined when grown in the presence and absence of antibiotic. Alkaline lysis methods were used for plasmid isolation. Vibrio spp. were predominantly plasmidless, except for a 47-kilobase (kb) plasmid. Atlantic coast isolates of A. salmonicida possessed four or six plasmids, with four smaller plasmids ranging in size from 4.3 to 8.1 kb being consistently observed. The plasmid profiles of antibiotic-sensitive ATCC strains were identical. The plasmid profiles of the Pacific coast isolates of A. salmonicida varied slightly from those of the Atlantic coast isolates with six plasmids observed, ranging in size from 4.2 to 8.9 kb. Resistance to the antibiotics was not altered following plasmid curing experiments and resistance was not transferable to Escherichia coli. Thus, resistance to oxytetracycline and streptomycin did not appear to be plasmid mediated.Key words: plasmids, antibiotics, Aeromonas, Vibrio, fish.
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Tonin, Patricia N., and Robert B. Grant. "Genetic and physical characterization of trimethoprim resistance plasmids from Shigella sonnei and Shigella flexneri." Canadian Journal of Microbiology 33, no. 10 (October 1, 1987): 905–13. http://dx.doi.org/10.1139/m87-157.
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Analysis of six Shigella flexneri and four S. sonnei isolates with trimethoprim (Tp) resistance from clinical cases in Ontario has shown that, in all isolates, the Tp resistance is mediated by gene(s) on conjugative, multiple antibiotic-resistance plasmids. The physical and genetic characterization of these plasmids revealed that there are three different Tp resistance plasmids. One group, composed of all six S. flexneri plasmids, consists of plasmids which are about 70 megadaltons (MDa) and inhibit the fertility of an Escherichia coli Hfr strain (Fi+). A representative member of this group, pPT4, demonstrates a weak incompatibility reaction with IncFI plasmid R455-2. Another group, three of the four S. sonnei plasmids, contains plasmids which are about 43 MDa, Fi−, and mediate propagation of phage PRD1. The third group, the remaining S. sonnei plasmid, is 53 MDa,fi+, mediates propagation of phages fd and MS2, and is incompatible with IncFII plasmid R100. These plasmids also have been differentiated by restriction endonuclease fragment profiles. Analysis of pPT4 has revealed that the Tp resistance of this plasmid is transposable. The transposon, Tn536, is different from previously described Tp resistance transposons; it is 16 MDa, and in addition to Tp, it encodes resistance to mercuric chloride ions, spectinomycin, streptomycin, and sulfonamides.
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Hunter, J. E. B., M. Bennett, C. A. Hart, J. C. Shelley, and J. R. Walton. "Apramycin-resistantEscherichia coliisolated from pigs and a stockman." Epidemiology and Infection 112, no. 3 (June 1994): 473–80. http://dx.doi.org/10.1017/s0950268800051177.
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SUMMARYEscherichia coliserotype O147:K89:K88a,c was found to be associated with outbreaks of diarrhoea in preweaner pigs of up to 4 weeks of age on a pig unit. Resistance to apramycin, gentamicin, netilmicin, tobramycin and other antibiotics was associated with conjugative plasmids of approximately 62 kb. The presence of a gene which encoded for the aminoglycoside acetyltransferase enzyme AAC(3)IV was confirmed by DNA hybridization.Samples collected during the following 12 months revealed widespread dissemination of these resistance plasmids in non-serotypable, non-haemolyticE. colithroughout the farm. Apramycin-resistantE. coliwere also isolated from a stockman and it appeared from plasmid profile analysis and antibiotic sensitivity testing that the human isolates carried the same plasmid as that carried by the porcineE. coli.Klebsiella pneumoniae, with a slightly smaller conjugative plasmid and similar resistance pattern, was isolated from the stockman's wife.
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Zhang, Hongyang, Mingding Chang, Xiaochen Zhang, Peiyan Cai, Yixin Dai, Tongzhen Song, Zhenzhou Wu, Haijin Xu, and Mingqiang Qiao. "Functional Identification and Evolutionary Analysis of Two Novel Plasmids Mediating Quinolone Resistance in Proteus vulgaris." Microorganisms 8, no. 7 (July 18, 2020): 1074. http://dx.doi.org/10.3390/microorganisms8071074.
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Plasmid-mediated quinolone resistance (PMQR) remains one of the main mechanisms of bacterial quinolone resistance and plays an important role in the transmission of antibiotic resistance genes (ARGs). In this study, two novel plasmids, p3M-2A and p3M-2B, which mediate quinolone resistance in Proteus vulgaris strain 3M (P3M) were identified. Of these, only p3M-2B appeared to be a qnrD-carrying plasmid. Both p3M-2A and p3M-2B could be transferred into Escherichia coli, and the latter caused a twofold change in ciprofloxacin resistance, according to the measured minimum inhibitory concentration (MIC). Plasmid curing/complementation and qRT-PCR results showed that p3M-2A can directly regulate the expression of qnrD in p3M-2B under treatment with ciprofloxacin, in which process, ORF1 was found to play an important role. Sequence alignments and phylogenetic analysis revealed the evolutionary relationships of all reported qnrD-carrying plasmids and showed that ORF1–4 in p3M-2B is the most conserved backbone for the normal function of qnrD-carrying plasmids. The identified direct repeats (DR) suggested that, from an evolutionary perspective, p3M-2B may have originated from the 2683-bp qnrD-carrying plasmid and may increase the possibility of plasmid recombination and then of qnrD transfer. To the best of our knowledge, this is the first identification of a novel qnrD-carrying plasmid isolated from a P. vulgaris strain of shrimp origin and a plasmid that plays a regulatory role in qnrD expression. This study also sheds new light on plasmid evolution and on the mechanism of horizontal transfer of ARGs encoded by plasmids.
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Schlüter, A., R. Szczepanowski, N. Kurz, S. Schneiker, I. Krahn, and A. Pühler. "Erythromycin Resistance-Conferring Plasmid pRSB105, Isolated from a Sewage Treatment Plant, Harbors a New Macrolide Resistance Determinant, an Integron-Containing Tn402-Like Element, and a Large Region of Unknown Function." Applied and Environmental Microbiology 73, no. 6 (January 19, 2007): 1952–60. http://dx.doi.org/10.1128/aem.02159-06.
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ABSTRACT The erythromycin resistance plasmid pRSB105 was previously isolated from an activated sludge bacterial community of a municipal wastewater treatment plant. Compilation of the complete pRSB105 nucleotide sequence revealed that the plasmid is 57,137 bp in size and has a mean G+C content of 56.66 mol%. The pRSB105 backbone is composed of two different replication and/or partitioning modules and a functional mobilization region encoding the mobilization genes mobCDE and mobBA. The first replicon (Rep1) is nearly identical to the corresponding replication module of the multiresistance plasmid pRSB101 isolated from an unknown activated sludge bacterium. Accordingly, pRSB101 and pRSB105 are sister plasmids belonging to a new plasmid family. The second replicon (Rep2) of pRSB105 was classified as a member of the IncP-6 group. While Rep1 confers replication ability only in γ-proteobacteria, Rep2 extents the host range of the plasmid since it is also functional in the β-proteobacterium Ralstonia eutropha. Plasmid pRSB105 harbors the macrolide resistance genes mel and mph, encoding, respectively, a predicted ABC-type efflux permease and a macrolide-2′-phosphotransferase. Erythromycin resistance is mainly attributed to mel, whereas mph contributes to erythromycin resistance to a lesser extent. The second resistance region, represented by an integron-containing Tn402-like element, includes a β-lactam (oxa10) and a trimethoprim (dfrB2) resistance gene cassette. In addition to antibiotic resistance modules, pRSB105 encodes a functional restriction/modification system and two nonresistance regions of unknown function. The presence of different mobile genetic elements that flank resistance and nonresistance modules on pRSB105 indicates that these elements were involved in acquisition of accessory plasmid modules. Comparative genomics of pRSB105 and related plasmids elucidated that pRSB105 evolved by integration of distinct modules from different plasmid sources, including Pseudomonas aeruginosa plasmids, and thus represents a mosaic plasmid.
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Dimitriu, Tatiana, Andrew C. Matthews, and Angus Buckling. "Increased copy number couples the evolution of plasmid horizontal transmission and plasmid-encoded antibiotic resistance." Proceedings of the National Academy of Sciences 118, no. 31 (July 29, 2021): e2107818118. http://dx.doi.org/10.1073/pnas.2107818118.
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Conjugative plasmids are mobile elements that spread horizontally between bacterial hosts and often confer adaptive phenotypes, including antimicrobial resistance (AMR). Theory suggests that opportunities for horizontal transmission favor plasmids with higher transfer rates, whereas selection for plasmid carriage favors less-mobile plasmids. However, little is known about the mechanisms leading to variation in transmission rates in natural plasmids or the resultant effects on their bacterial host. We investigated the evolution of AMR plasmids confronted with different immigration rates of susceptible hosts. Plasmid RP4 did not evolve in response to the manipulations, but plasmid R1 rapidly evolved up to 1,000-fold increased transfer rates in the presence of susceptible hosts. Most evolved plasmids also conferred on their hosts the ability to grow at high concentrations of antibiotics. This was because plasmids evolved greater copy numbers as a function of mutations in the copA gene controlling plasmid replication, causing both higher transfer rates and AMR. Reciprocally, plasmids with increased conjugation rates also evolved when selecting for high levels of AMR, despite the absence of susceptible hosts. Such correlated selection between plasmid transfer and AMR could increase the spread of AMR within populations and communities.
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Schwanbeck, Julian, Wolfgang Bohne, Ufuk Hasdemir, Uwe Groß, Yvonne Pfeifer, Boyke Bunk, Thomas Riedel, et al. "Detection of a New Resistance-Mediating Plasmid Chimera in a blaOXA-48-Positive Klebsiella pneumoniae Strain at a German University Hospital." Microorganisms 9, no. 4 (March 31, 2021): 720. http://dx.doi.org/10.3390/microorganisms9040720.
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Mobile genetic elements, such as plasmids, facilitate the spread of antibiotic resistance genes in Enterobacterales. In line with this, we investigated the plasmid-resistome of seven blaOXA-48 gene-carrying Klebsiella pneumoniae isolates, which were isolated between 2013 and 2014 at the University Medical Center in Göttingen, Germany. All isolates were subjected to complete genome sequencing including the reconstruction of entire plasmid sequences. In addition, phenotypic resistance testing was conducted. The seven isolates comprised both disease-associated isolates and colonizers isolated from five patients. They fell into two clusters of three sequence type (ST)101 and two ST11 isolates, respectively; and ST15 and ST23 singletons. The seven isolates harbored various plasmids of the incompatibility (Inc) groups IncF, IncL/M, IncN, IncR, and a novel plasmid chimera. All blaOXA-48 genes were encoded on the IncL/M plasmids. Of note, distinct phenotypical resistance patterns associated with different sets of resistance genes encoded by IncL/M and IncR plasmids were observed among isolates of the ST101 cluster in spite of high phylogenetic relatedness of the bacterial chromosomes, suggesting nosocomial transmission. This highlights the importance of plasmid uptake and plasmid recombination events for the fast generation of resistance variability after clonal transmission. In conclusion, this study contributes a piece in the puzzle of molecular epidemiology of resistance gene-carrying plasmids in K. pneumoniae in Germany.
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Heiden, Stefan E., Katharina Sydow, Stephan Schaefer, Ingo Klempien, Veronika Balau, Peter Bauer, Nils-Olaf Hübner, and Katharina Schaufler. "Nearly Identical Plasmids Encoding VIM-1 and Mercury Resistance in Enterobacteriaceae from North-Eastern Germany." Microorganisms 9, no. 7 (June 22, 2021): 1345. http://dx.doi.org/10.3390/microorganisms9071345.
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The emergence of carbapenemase-producing Enterobacteriaceae limits therapeutic options and presents a major public health problem. Resistances to carbapenems are mostly conveyed by metallo-beta-lactamases (MBL) including VIM, which are often encoded on resistance plasmids. We characterized four VIM-positive isolates that were obtained as part of a routine diagnostic screening from two laboratories in north-eastern Germany between June and August 2020. Whole-genome sequencing was performed to address (a) phylogenetic properties, (b) plasmid content, and (c) resistance gene carriage. In addition, we performed phenotypic antibiotic and mercury resistance analyses. The genomic analysis revealed three different bacterial species including C. freundii, E. coli and K. oxytoca with four different sequence types. All isolates were geno- and phenotypically multidrug-resistant (MDR) and the phenotypic profile was explained by the underlying resistance gene content. Three isolates of four carried nearly identical VIM-1-resistance plasmids, which in addition encoded a mercury resistance operon and showed some similarity to two publicly available plasmid sequences from sources other than the two laboratories above. Our results highlight the circulation of a nearly identical IncN-type VIM-1-resistance plasmid in different Enterobacteriaceae in north-eastern Germany.
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Carroll, Amanda C., and Alex Wong. "Plasmid persistence: costs, benefits, and the plasmid paradox." Canadian Journal of Microbiology 64, no. 5 (May 2018): 293–304. http://dx.doi.org/10.1139/cjm-2017-0609.
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Plasmids are extrachromosomal DNA elements that can be found throughout bacteria, as well as in other domains of life. Nonetheless, the evolutionary processes underlying the persistence of plasmids are incompletely understood. Bacterial plasmids may encode genes for traits that are sometimes beneficial to their hosts, such as antimicrobial resistance, virulence, heavy metal tolerance, and the catabolism of unique nutrient sources. In the absence of selection for these traits, however, plasmids generally impose a fitness cost on their hosts. As such, plasmid persistence presents a conundrum: models predict that costly plasmids will be lost over time or that beneficial plasmid genes will be integrated into the host genome. However, laboratory and comparative studies have shown that plasmids can persist for long periods, even in the absence of positive selection. Several hypotheses have been proposed to explain plasmid persistence, including host-plasmid co-adaptation, plasmid hitchhiking, cross-ecotype transfer, and high plasmid transfer rates, but there is no clear evidence that any one model adequately resolves the plasmid paradox.
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Gebre-Yohannes, A., and B. S. Drasar. "Molecular epidemiology of plasmid patterns inShigella flexneritypes 1–6." Epidemiology and Infection 107, no. 2 (October 1991): 321–34. http://dx.doi.org/10.1017/s0950268800048962.
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SUMMARYA total of 123 drug-resistant and drug-sensitiveShigella flexneritypes 1–6, and theirEscherichia coliK12 transconjugants were used for plasmid profile analysis by agarose gel electrophoresis. Resistance factors (R-factors) were further characterized by incompatibility testing.The overall distribution of small plasmids inS. flexnerishowed that a cryptic plasmid of about 4·6 Kb was found in all serotypes, and a plasmid of about 4·2 Kb was found in serotypes 1–4.Shigella flexneritypes 2, 4 and 6 showed a 6·5 Kb plasmid which correlated with SSu-resistance. AllS. flexneriserotypes harboured large plasmids of about 217 Kb. Plasmid profile analysis ofS. flexneriin Ethiopia showed a high degree of uniformity within individual serotypes. However, there was a limited variability which, at times, could be useful for epidemiological investigation.Shigella flexneriserotypes 1–6 harboured resistance plasmids with diverse molecular weights but mostly belonging to incompatibility groups N and X.
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Johnson, Timothy J., Kylie E. Siek, Sara J. Johnson, and Lisa K. Nolan. "DNA Sequence and Comparative Genomics of pAPEC-O2-R, an Avian Pathogenic Escherichia coli Transmissible R Plasmid." Antimicrobial Agents and Chemotherapy 49, no. 11 (November 2005): 4681–88. http://dx.doi.org/10.1128/aac.49.11.4681-4688.2005.
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ABSTRACT In this study, a 101-kb IncF plasmid from an avian pathogenic Escherichia coli (APEC) strain (APEC O2) was sequenced and analyzed, providing the first completed APEC plasmid sequence. This plasmid, pAPEC-O2-R, has functional transfer and antimicrobial resistance-encoding regions. The resistance-encoding region encodes resistance to eight groups of antimicrobial agents, including silver and other heavy metals, quaternary ammonium compounds, tetracycline, sulfonamides, aminoglycosides, trimethoprim, and beta-lactam antimicrobial agents. This region of the plasmid is unique among previously described IncF plasmids in that it possesses a class 1 integron that harbors three gene cassettes and a heavy metal resistance operon. This region spans 33 kb and is flanked by the RepFII plasmid replicon and an assortment of plasmid maintenance genes. pAPEC-O2-R also contains a 32-kb transfer region that is nearly identical to that found in the E. coli F plasmid, rendering it transferable by conjugation to plasmid-less strains of bacteria, including an APEC strain, a fecal E. coli strain from an apparently healthy bird, a Salmonella enterica serovar Typhimurium strain, and a uropathogenic E. coli strain from humans. Differences in the G+C contents of individual open reading frames suggest that various regions of pAPEC-O2-R had dissimilar origins. The presence of pAPEC-O2-R-like plasmids that encode resistance to multiple antimicrobial agents and that are readily transmissible from APEC to other bacteria suggests the possibility that such plasmids may serve as a reservoir of resistance genes for other bacteria of animal and human health significance.
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Gómez-Martínez, Jessica, Rosa del Carmen Rocha-Gracia, Elena Bello-López, Miguel Angel Cevallos, Miguel Castañeda-Lucio, Alma López-García, Yolanda Sáenz, Guadalupe Jiménez-Flores, Gerardo Cortés-Cortés, and Patricia Lozano-Zarain. "A Plasmid Carrying blaIMP-56 in Pseudomonas aeruginosa Belonging to a Novel Resistance Plasmid Family." Microorganisms 10, no. 9 (September 17, 2022): 1863. http://dx.doi.org/10.3390/microorganisms10091863.
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blaIMP and blaVIM are the most detected plasmid-encoded carbapenemase genes in Pseudomonas aeruginosa. Previous studies have reported plasmid sequences carrying blaIMP variants, except blaIMP-56. In this study, we aimed to characterize a plasmid carrying blaIMP-56 in a P. aeruginosa strain isolated from a Mexican hospital. The whole genome of P. aeruginosa strain PE52 was sequenced using Illumina Miseq 2 × 150 bp, with 5 million paired-end reads. We characterized a 27 kb plasmid (pPE52IMP) that carried blaIMP-56. The phylogenetic analysis of RepA in pPE52IMP and 33 P. aeruginosa plasmids carrying resistance genes reported in the GenBank revealed that pPE52IMP and four plasmids (pMATVIM-7, unnamed (FDAARGOS_570), pD5170990, and pMRVIM0713) were in the same clade. These closely related plasmids belonged to the MOBP11 subfamily and had similar backbones. Another plasmid (p4130-KPC) had a similar backbone to pPE52IMP; however, its RepA was truncated. In these plasmids, the resistance genes blaKPC-2, blaVIM variants, aac(6′)-Ib4, blaOXA variants, and blaIMP-56 were inserted between phd and resolvase genes. This study describes a new family of plasmids carrying resistance genes, with a similar backbone, the same RepA, and belonging to the MOBP11 subfamily in P. aeruginosa. In addition, our characterized plasmid harboring blaIMP-56 (pPE52IMP) belongs to this family.
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Phan, Minh-Duy, Claire Kidgell, Satheesh Nair, Kathryn E. Holt, Arthur K. Turner, Jason Hinds, Philip Butcher, et al. "Variation in Salmonella enterica Serovar Typhi IncHI1 Plasmids during the Global Spread of Resistant Typhoid Fever." Antimicrobial Agents and Chemotherapy 53, no. 2 (November 17, 2008): 716–27. http://dx.doi.org/10.1128/aac.00645-08.
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ABSTRACT A global collection of plasmids of the IncHI1 incompatibility group from Salmonella enterica serovar Typhi were analyzed by using a combination of DNA sequencing, DNA sequence analysis, PCR, and microarrays. The IncHI1 resistance plasmids of serovar Typhi display a backbone of conserved gene content and arrangement, within which are embedded preferred acquisition sites for horizontal DNA transfer events. The variable regions appear to be preferred acquisition sites for DNA, most likely through composite transposition, which is presumably driven by the acquisition of resistance genes. Plasmid multilocus sequence typing, a molecular typing method for IncHI1 plasmids, was developed using variation in six conserved loci to trace the spread of these plasmids and to elucidate their evolutionary relationships. The application of this method to a collection of 36 IncHI1 plasmids revealed a chronological clustering of plasmids despite their difference in geographical origins. Our findings suggest that the predominant plasmid types present after 1993 have not evolved directly from the earlier predominant plasmid type but have displaced them. We propose that antibiotic selection acts to maintain resistance genes on the plasmid, but there is also competition between plasmids encoding the same resistance phenotype.
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Akter, Sanjida, A. M. Masudul Azad Chowdhury, and Sohana Akter Mina. "Antibiotic Resistance and Plasmid Profiling of Escherichia coli Isolated from Human Sewage Samples." Microbiology Insights 14 (January 2021): 117863612110168. http://dx.doi.org/10.1177/11786361211016808.
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In developing countries, the occurrence of antibiotic resistance is increasing day by day and antibiotic resistant microorganisms are being found in almost every environmental setting. Plasmids are considered as the main vector in the procurement and propagation of antibiotic resistance in many microorganisms such as Escherichia coli ( E. coli). The goal of this study was to examine the antibiotic resistance and screening of plasmid in E. coli strains which were previously identified from human sewage samples. During this study antibiotic susceptibility of E. coli isolates were determined by Kirby-Bauer disk diffusion method against 5 antibiotics (ampicilin, ceftriaxone, amoxicillin, ciprofloxacin, azithromycin). Furthermore, plasmid extraction of each isolate was done according to the protocol of FavorPrepTMPlasmid Mini Kit and plasmid profiling was done by agarose gel electrophoresis. In antibiotic sensitivity test, all E. coli strains showed resistance to ampicilin, amoxicillin, and ceftriaxone. In the plasmid profiling, it was revealed that all the isolates of E. coli harbored plasmids. The plasmid sizes ranged from approximately 1.5 to 15 kb. The findings of this study prove the consequences of antibiotic resistance as well as relationship of plasmid with antibiotic resistance which necessitates proper surveillance on antibiotic usage in the developing countries.
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Cairns, Johannes, Matti Jalasvuori, Ville Ojala, Michael Brockhurst, and Teppo Hiltunen. "Conjugation is necessary for a bacterial plasmid to survive under protozoan predation." Biology Letters 12, no. 2 (February 2016): 20150953. http://dx.doi.org/10.1098/rsbl.2015.0953.
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Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogen Serratia marcescens . A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of conjugative plasmids with implications for bacterial evolution and the spread of antibiotic resistance genes.
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Cantin, Mario, Josée Harel, Robert Higgins, and Marcelo Gottschalk. "Antimicrobial Resistance Patterns and Plasmid Profiles of Streptococcus Suis Isolates." Journal of Veterinary Diagnostic Investigation 4, no. 2 (April 1992): 170–74. http://dx.doi.org/10.1177/104063879200400209.
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Streptococcus suis isolates recovered from diseased animals in Quebec and western Canada and from human cases in Europe were tested for their susceptibility to different antimicrobial agents and screened for their plasmid content. Most isolates from Quebec were clindamycin, erythromycin, and tetracycline resistant; animal isolates from western Canada were notably less resistant to clindamycin and erythromycin, whereas human isolates were considerably more susceptible to most antimicrobials tested.1 More than 60% of isolates had plasmids that ranged from 1.5 to 35 kilobases (kb). Of the 7 plasmid profiles found, 2 were particularly frequent in isolates from Quebec and western Canada, suggesting the presence of epidemic strains in the swine population. A particular plasmid band of about 5 kb was present in most Canadian isolates. When this band was used as a probe in colony and Southem blot hybridization, most isolates harboring the 5-kb plasmid hybridized, even though their plasmid profiles were different. Human isolates from Europe differed in their plasmid content from Canadian isolates of animal origin. Although a high degree of antimicrobial resistance was associated with the presence of plasmids in most isolates, it was not possible to establish a causative relationship.
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Guillard, Thomas, Emmanuelle Cambau, Catherine Neuwirth, Thomas Nenninger, Aurore Mbadi, Lucien Brasme, Véronique Vernet-Garnier, Odile Bajolet, and Christophe de Champs. "Description of a 2,683-Base-Pair Plasmid ContainingqnrDin Two Providencia rettgeri Isolates." Antimicrobial Agents and Chemotherapy 56, no. 1 (October 10, 2011): 565–68. http://dx.doi.org/10.1128/aac.00081-11.
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ABSTRACTqnrgenes are plasmid-mediated quinolone resistance genes mainly harbored on large conjugative multiresistant plasmids. TheqnrDgene was recently observed inSalmonella entericaon a small nonconjugative plasmid (p2007057). We describe two strains ofProvidencia rettgeriharboringqnrDon nonconjugative plasmids. The plasmids were 99% identical, with 2,683 bp and four open reading frames, includingqnrD, but exhibited only 53% identity with the plasmid found inS. enterica.
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Kloos, Julia, João A. Gama, Joachim Hegstad, Ørjan Samuelsen, and Pål J. Johnsen. "Piggybacking on Niche Adaptation Improves the Maintenance of Multidrug-Resistance Plasmids." Molecular Biology and Evolution 38, no. 8 (March 24, 2021): 3188–201. http://dx.doi.org/10.1093/molbev/msab091.
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Abstract The persistence of plasmids in bacterial populations represents a puzzling evolutionary problem with serious clinical implications due to their role in the ongoing antibiotic resistance crisis. Recently, major advancements have been made toward resolving this “plasmid paradox” but mainly in a nonclinical context. Here, we propose an additional explanation for the maintenance of multidrug-resistance plasmids in clinical Escherichia coli strains. After coevolving two multidrug-resistance plasmids encoding resistance to last resort carbapenems with an extraintestinal pathogenic E. coli strain, we observed that chromosomal media adaptive mutations in the global regulatory systems CCR (carbon catabolite repression) and ArcAB (aerobic respiration control) pleiotropically improved the maintenance of both plasmids. Mechanistically, a net downregulation of plasmid gene expression reduced the fitness cost. Our results suggest that global chromosomal transcriptional rewiring during bacterial niche adaptation may facilitate plasmid maintenance.
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Berg, Tracey, Neville Firth, Sumalee Apisiridej, Anusha Hettiaratchi, Amornrut Leelaporn, and Ronald A. Skurray. "Complete Nucleotide Sequence of pSK41: Evolution of Staphylococcal Conjugative Multiresistance Plasmids." Journal of Bacteriology 180, no. 17 (September 1, 1998): 4350–59. http://dx.doi.org/10.1128/jb.180.17.4350-4359.1998.
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ABSTRACT The 46.4-kb nucleotide sequence of pSK41, a prototypical multiresistance plasmid from Staphylococcus aureus, has been determined, representing the first completely sequenced conjugative plasmid from a gram-positive organism. Analysis of the sequence has enabled the identification of the probable replication, maintenance, and transfer functions of the plasmid and has provided insights into the evolution of a clinically significant group of plasmids. The basis of deletions commonly associated with pSK41 family plasmids has been investigated, as has the observed insertion site specificity of Tn552-like β-lactamase transposons within them. Several of the resistance determinants carried by pSK41-like plasmids were found to be located on up to four smaller cointegrated plasmids. pSK41 and related plasmids appear to represent a consolidation of antimicrobial resistance functions, collected by a preexisting conjugative plasmid via transposon insertion and IS257-mediated cointegrative capture of other plasmids.
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Zheng, Bo, Haruyoshi Tomita, Takako Inoue, and Yasuyoshi Ike. "Isolation of VanB-Type Enterococcus faecalis Strains from Nosocomial Infections: First Report of the Isolation and Identification of the Pheromone-Responsive Plasmids pMG2200, Encoding VanB-Type Vancomycin Resistance and a Bac41-Type Bacteriocin, and pMG2201, Encoding Erythromycin Resistance and Cytolysin (Hly/Bac)." Antimicrobial Agents and Chemotherapy 53, no. 2 (November 24, 2008): 735–47. http://dx.doi.org/10.1128/aac.00754-08.
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ABSTRACT Eighteen identical VanB-type Enterococcus faecalis isolates that were obtained from different hospitalized patients were examined for their drug resistance and plasmid DNAs. Of the 18 strains, 12 strains exhibited resistance to erythromycin (Em), gentamicin (Gm), kanamycin (Km), tetracycline (Tc), and vancomycin (Van) and produced cytolysin (Hly/Bac) and a bacteriocin (Bac) active against E. faecalis strains. Another six of the strains exhibited resistance to Gm, Km, Tc, and Van and produced a bacteriocin. Em and Van resistance was transferred individually to E. faecalis FA2-2 strains at a frequency of about 10−4 per donor cell by broth mating. The Em-resistant transconjugants and the Van-resistant transconjugants harbored a 65.7-kbp plasmid and a 106-kbp plasmid, respectively. The 106-kbp and 65.7-kbp plasmids isolated from the representative E. faecalis NKH15 strains were designated pMG2200 and pMG2201, respectively. pMG2200 conferred vancomycin resistance and bacteriocin activity on the host strain and responded to the synthetic pheromone cCF10 for pCF10, while pMG2201 conferred erythromycin resistance and cytolysin activity on its host strain and responded to the synthetic pheromone cAD1 for pAD1. The complete DNA sequence of pMG2200 (106,527 bp) showed that the plasmid carried a Tn1549-like element encoding vanB2-type resistance and the Bac41-like bacteriocin genes of pheromone-responsive plasmid pYI14. The plasmid contained the regulatory region found in pheromone-responsive plasmids and encoded the genes prgX and prgQ, which are the key negative regulatory elements for plasmid pCF10. pMG2200 also encoded TraE1, a key positive regulator of plasmid pAD1, indicating that pMG2200 is a naturally occurring chimeric plasmid that has a resulting prgX-prgQ-traE1 genetic organization in the regulatory region of the pheromone response. The functional oriT region and the putative relaxase gene of pMG2200 were identified and found to differ from those of pCF10 and pAD1. The putative relaxase of pMG2200 was classified as a member of the MOBMG family, which is found in pheromone-independent plasmid pHTβ of the pMG1-like plasmids. This is the first report of the isolation and characterization of a pheromone-responsive highly conjugative plasmid encoding vanB resistance.
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Wu, Fei, Yuanyuan Ying, Min Yin, Yi Jiang, Chongyang Wu, Changrui Qian, Qianqian Chen, et al. "Molecular Characterization of a Multidrug-Resistant Klebsiella pneumoniae Strain R46 Isolated from a Rabbit." International Journal of Genomics 2019 (August 18, 2019): 1–12. http://dx.doi.org/10.1155/2019/5459190.
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To investigate the mechanisms of multiple resistance and the horizontal transfer of resistance genes in animal pathogens, we characterized the molecular structures of the resistance gene-related sequences in a multidrug-resistant Klebsiella pneumoniae strain R46 isolated from a rabbit. Molecular cloning was performed to clone the resistance genes, and minimum inhibitory concentrations (MICs) were measured to determine the resistance characteristics of the cloned genes and related strains. A conjugation experiment was conducted to assess the transferability of the resistance plasmids. Sequencing and comparative genomic methods were used to analyze the structures of the resistance gene-related sequences. The K. pneumoniae R46 genome consisted of a chromosome and three resistance plasmids named pR46-27, pR46-42, and pR46-270, respectively. The whole genome encoded 34 antibiotic resistance genes including a newly identified chromosome-encoded florfenicol resistance gene named mdfA2. pR46-270, besides encoding 26 antibiotic resistance genes, carried four clusters of heavy metal resistance genes and several virulence-related genes or gene clusters. The plasmid-encoded resistance genes were mostly associated with mobile genetic elements. The plasmid with the most similarity to the floR gene-harboring plasmid pR46-27 was pCTXM-2271, a plasmid from Escherichia coli. The results of this work demonstrated that the plasmids with multidrug resistance genes were present in animal-derived bacteria and more florfenicol resistance genes such as mdfA2 could be present in bacterial populations. The resistance genes encoded on the plasmids may spread between the bacteria of different species or genera and cause the resistance dissemination.
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Khezri, Abdolrahman, Ekaterina Avershina, and Rafi Ahmad. "Plasmid Identification and Plasmid-Mediated Antimicrobial Gene Detection in Norwegian Isolates." Microorganisms 9, no. 1 (December 27, 2020): 52. http://dx.doi.org/10.3390/microorganisms9010052.
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Norway is known for being one of the countries with the lowest levels of antimicrobial resistance (AMR). AMR, through acquired genes located on transposons or conjugative plasmids, is the horizontal transmission of genes required for a given bacteria to withstand antibiotics. In this work, bioinformatic analysis of whole-genome sequences and hybrid assembled data from Escherichia coli, and Klebsiella pneumoniae isolates from Norwegian patients was performed. For detection of putative plasmids in isolates, the plasmid assembly mode in SPAdes was used, followed by annotation of resulting contigs using PlasmidFinder and two curated plasmid databases (Brooks and PLSDB). Furthermore, ResFinder and Comprehensive Antibiotic Resistance Database (CARD) were used for the identification of antibiotic resistance genes (ARGs). The IncFIB plasmid was detected as the most prevalent plasmid in both E. coli, and K. pneumoniae isolates. Furthermore, ARGs such as aph(3″)-Ib, aph(6)-Id, sul1, sul2, tet(D), and qnrS1 were identified as the most abundant plasmid-mediated ARGs in Norwegian E. coli and K. pneumoniae isolates, respectively. Using hybrid assembly, we were able to locate plasmids and predict ARGs more confidently. In conclusion, plasmid identification and ARG detection using whole-genome sequencing data are heavily dependent on the database of choice; therefore, it is best to use several tools and/or hybrid assembly for obtaining reliable identification results.
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Ababneh, Qutaiba, Sara Al Sbei, Ziad Jaradat, Sebawe Syaj, Neda’a Aldaken, Hamza Ababneh, and Zeina Inaya. "Extensively drug-resistant Acinetobacter baumannii: role of conjugative plasmids in transferring resistance." PeerJ 11 (January 25, 2023): e14709. http://dx.doi.org/10.7717/peerj.14709.
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Acinetobacter baumannii is one of the most successful pathogens that can cause difficult-to-treat nosocomial infections. Outbreaks and infections caused by multi-drug resistant A. baumannii are prevalent worldwide, with only a few antibiotics are currently available for treatments. Plasmids represent an ideal vehicle for acquiring and transferring resistance genes in A. baumannii. Five extensively drug-resistant A. baumannii clinical isolates from three major Jordanian hospitals were fully sequenced. Whole-Genome Sequences (WGS) were used to study the antimicrobial resistance and virulence genes, sequence types, and phylogenetic relationship of the isolates. Plasmids were characterized In-silico, followed by conjugation, and plasmid curing experiments. Eight plasmids were recovered; resistance plasmids carrying either aminoglycosides or sulfonamide genes were detected. Chromosomal resistance genes included blaOXA-66, blaOXA-91, and blaOXA-23,and the detected virulence factors were involved in biofilm formation, adhesion, and many other mechanisms. Conjugation and plasmid curing experiments resulted in the transfer or loss of several resistance phenotypes. Plasmid profiling along with phylogenetic analyses revealed high similarities between two A. baumannii isolates recovered from two different intensive care units (ICU). The high similarities between the isolates of the study, especially the two ICU isolates, suggest that there is a common A. baumannii strain prevailing in different ICU wards in Jordanian hospitals. Three resistance genes were plasmid-borne, and the transfer of the resistance phenotype emphasizes the role and importance of conjugative plasmids in spreading resistance among A. baumannii clinical strains.
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Brown, D. J., E. J. Threlfall, and B. Rowe. "Instability of multiple drug resistance plasmids inSalmonella typhimuriumisolated from poultry." Epidemiology and Infection 106, no. 2 (April 1991): 247–57. http://dx.doi.org/10.1017/s0950268800048391.
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SUMMARYPlasmids in five strains ofSalmonella typhimuriumresistant to ampicillin, chloramphenicol, gentamicin, neomycin/kanamycin, streptomycin, sulphonamides, tetracyclines and trimethoprim (ACGKSSuTTm), CGKSSuTTm, ACSSuT or CSSuT which had been isolated from poultry in the first 3 months of 1989 have been characterized and compared with plasmids in two strains of R-types ACGKSSuTTm and ASSuTTm isolated from two patients later in the year. With the exception of the human isolate of R-type ASSuTTm, all strains carried two non-conjugative plasmids, one coding for SSu and belonging to incompatibility group Q, and a second coding for multiple resistance and belonging to the FImeincompatibility group. The human isolate of R-type ASSuTTm did not carry theIncQ, SSu plasmid but like the poultry isolates, carried a non-conjugative FImeplasmid.Restriction endonuclease digestion with the enzymesEcoR I,PstI andHindIII demonstrated that the FImeplasmids from strains of different R-types showed a high degree of homology but exhibited numerous fragment size polymorphisms. The restriction digest fingerprint of plasmids in the human isolate of R-type ACGKSSuTTm was indistinguishable from a poultry isolate of the same R-type. Analysis of segregants of one of the poultry isolates of R-type ACGKSSuTTm demonstrated that resistance determinants could be rapidly lost from the FImeplasmid to give rise to a number of R-types and fingerprint patterns. Loss of tetracycline resistance from this plasmid appeared to be correlated with the integration of other plasmid-mediated resistances into the bacterial chromosome. Evidence is presented for the rapid loss of antimicrobial resistance determinants from a multiple resistance plasmid of the FImeincompatibility group in response to withdrawal of antibiotic selective pressure.
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Chen, Chin-Yi, Rebecca L. Lindsey, Terence P. Strobaugh, Jonathan G. Frye, and Richard J. Meinersmann. "Prevalence of ColE1-Like Plasmids and Kanamycin Resistance Genes in Salmonella enterica Serovars." Applied and Environmental Microbiology 76, no. 20 (August 6, 2010): 6707–14. http://dx.doi.org/10.1128/aem.00692-10.
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ABSTRACT Multi-antimicrobial-resistant Salmonella enterica strains frequently carry resistance genes on plasmids. Recent studies focus heavily on large conjugative plasmids, and the role that small plasmids play in resistance gene transfer is largely unknown. To expand our previous studies in assessing the prevalence of the isolates harboring ColE1-like plasmids carrying the aph gene responsible for kanamycin resistance (Kanr) phenotypes, 102 Kanr Salmonella isolates collected through the National Antimicrobial Resistance Monitoring System (NARMS) in 2005 were screened by PCR using ColE1 primer sets. Thirty isolates were found to be positive for ColE1-like replicon. Plasmids from 23 isolates were able to propagate in Escherichia coli and were subjected to further characterization. Restriction mapping revealed three major plasmid groups found in three or more isolates, with each group consisting of two to three subtypes. The aph genes from the Kanr Salmonella isolates were amplified by PCR, sequenced, and showed four different aph(3′)-I genes. The distribution of the ColE1 plasmid groups in association with the aph gene, Salmonella serovar, and isolate source demonstrated a strong linkage of the plasmid with S. enterica serovar Typhimurium DT104. Due to their high copy number and mobility, the ColE1-like plasmids may play a critical role in transmission of antibiotic resistance genes among enteric pathogens, and these findings warrant a close monitoring of this plasmid incompatibility group.
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Pan, Jing-Cao, Rong Ye, Hao-Qiu Wang, Hai-Qing Xiang, Wei Zhang, Xin-Fen Yu, Dong-Mei Meng, and Zhe-Sheng He. "Vibrio cholerae O139 Multiple-Drug Resistance Mediated by Yersinia pestis pIP1202-Like Conjugative Plasmids." Antimicrobial Agents and Chemotherapy 52, no. 11 (August 18, 2008): 3829–36. http://dx.doi.org/10.1128/aac.00375-08.
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ABSTRACT A conjugative plasmid, pMRV150, which mediated multiple-drug resistance (MDR) to at least six antibiotics, including ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole, was identified in a Vibrio cholerae O139 isolate from Hangzhou, eastern China, in 2004. According to partial pMRV150 DNA sequences covering 15 backbone regions, the plasmid is most similar to pIP1202, an IncA/C plasmid in an MDR Yersinia pestis isolate from a Madagascar bubonic plague patient, at an identity of 99.99% (22,180/22,183 nucleotides). pMRV150-like plasmids were found in only 7.69% (1/13) of the O139 isolates tested during the early period of the O139 epidemic in Hangzhou (1994, 1996, and 1997); then the frequency increased gradually from 60.00% (3/5) during 1998 and 1999 to 92.16% (47/51) during 2000 to 2006. Most (42/51) of the O139 isolates bearing pMRV150-like plasmids were resistant to five to six antibiotics, whereas the plasmid-negative isolates were resistant only to one to three antibiotics. In 12 plasmid-bearing O139 isolates tested, the pMRV150-like plasmids ranged from approximately 140 kb to 170 kb and remained at approximately 1 or 2 copies per cell. High (4.50 × 10−2 and 3.08 × 10−2) and low (0.88 × 10−8 to 3.29 × 10−5) plasmid transfer frequencies, as well as no plasmid transfer (under the detection limit), from these O139 isolates to the Escherichia coli recipient were observed. The emergence of pMRV150-like or pIP1202-like plasmids in many bacterial pathogens and nonpathogens occupying diverse niches with global geographical distribution indicates an increasing risk to public health worldwide. Careful tracking of these plasmids in the microbial ecosystem is warranted.
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Hazen, Tracy H., LiCheng Zhao, Mallory A. Boutin, Angela Stancil, Gwen Robinson, Anthony D. Harris, David A. Rasko, and J. Kristie Johnson. "Comparative Genomics of an IncA/C Multidrug Resistance Plasmid from Escherichia coli and Klebsiella Isolates from Intensive Care Unit Patients and the Utility of Whole-Genome Sequencing in Health Care Settings." Antimicrobial Agents and Chemotherapy 58, no. 8 (June 9, 2014): 4814–25. http://dx.doi.org/10.1128/aac.02573-14.
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ABSTRACTThe IncA/C plasmids have been implicated for their role in the dissemination of β-lactamases, including gene variants that confer resistance to expanded-spectrum cephalosporins, which are often the treatment of last resort against multidrug-resistant, hospital-associated pathogens. AblaFOX-5gene was detected in 14Escherichia coliand 16Klebsiellaisolates that were cultured from perianal swabs of patients admitted to an intensive care unit (ICU) of the University of Maryland Medical Center (UMMC) in Baltimore, MD, over a span of 3 years. Four of the FOX-encoding isolates were obtained from subsequent samples of patients that were initially negative for an AmpC β-lactamase upon admission to the ICU, suggesting that the AmpC β-lactamase-encoding plasmid was acquired while the patient was in the ICU. The genomes of fiveE. coliisolates and sixKlebsiellaisolates containingblaFOX-5were selected for sequencing based on their plasmid profiles. An ∼167-kb IncA/C plasmid encoding the FOX-5 β-lactamase, a CARB-2 β-lactamase, additional antimicrobial resistance genes, and heavy metal resistance genes was identified. Another FOX-5-encoding IncA/C plasmid that was nearly identical except for a variable region associated with the resistance genes was also identified. To our knowledge, these plasmids represent the first FOX-5-encoding plasmids sequenced. We used comparative genomics to describe the genetic diversity of a plasmid encoding a FOX-5 β-lactamase relative to the whole-genome diversity of 11E. coliandKlebsiellaisolates that carry this plasmid. Our findings demonstrate the utility of whole-genome sequencing for tracking of plasmid and antibiotic resistance gene distribution in health care settings.
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Otokunefor, Kome, Victor Ogechi Osogho, and Chijindu Precious Nwankwo. "Escherichia coli as Possible Agents of Spread of Multidrug Resistance in Port Harcourt, Rivers State." Annals of Science and Technology 4, no. 1 (June 1, 2019): 16–21. http://dx.doi.org/10.2478/ast-2019-0002.
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AbstractMultidrug resistance (MDR) continues to be a growing global issue. The problem of MDR is fuelled in part by the spread of the genes encoding resistance horizontally which is linked particularly to conjugation involving plasmids. Studies have demonstrated the presence of plasmids in drug resistant isolates, few have shown a link between these plasmids and drug resistance via plasmid curing especially in our locale. This study set out to explore this link inEscherichia coliisolates from Port Harcourt, Nigeria. Plasmid curing was done on a selection of clinical and non-clinical bacteria using acridine orange and antibiotic susceptibility testing carried out on both cured and uncured variants. Data generated was analysed to ascertain the multiple antibiotic resistance (MAR) index and MDR of each isolate. Data was then compared to ascertain effects of plasmid curing on antibiotic resistance of the isolates. Results revealed a decrease in resistance to 7 of 8 antibiotics following plasmid curing. The highest change was noted in ceftazidime (40%), followed by ofloxacin (26.7%). Plasmid curing caused a shift in MAR index values of isolates from higher to lower indices. At MAR index values of ≤0.25 occurrence increased from 5% to 36.7% while at MAR index values ≥0.75, occurrence reduced from 29.9% to 10.0%. A reduction in the degree of MDR was noted (from 55% to 36.7%). Strikingly, the reduction in MDR level of non-clinical isolates was 30% as opposed to 3.4% in the clinical isolates. This study shows a link between plasmids and antibiotic resistance. For the non-clinical isolates, the high-level link between MDR and plasmid carriage could indicate a higher use of antimicrobials in non-clinical rather than clinical settings. Additionally, it could be an indicator for a higher risk of the transfer of MDR determinants from non-clinical sources to human populations in our locale.
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Hansen, Katrine Hartung, Valeria Bortolaia, Christine Ahl Nielsen, Jesper Boye Nielsen, Kristian Schønning, Yvonne Agersø, and Luca Guardabassi. "Host-Specific Patterns of Genetic Diversity among IncI1-Iγ and IncK Plasmids Encoding CMY-2 β-Lactamase in Escherichia coli Isolates from Humans, Poultry Meat, Poultry, and Dogs in Denmark." Applied and Environmental Microbiology 82, no. 15 (May 27, 2016): 4705–14. http://dx.doi.org/10.1128/aem.00495-16.
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ABSTRACTCMY-2 is the most common plasmid-mediated AmpC β-lactamase inEscherichia coliisolates of human and animal origin. The aim of this study was to elucidate the epidemiology of CMY-2-producingE. coliin Denmark. Strain and plasmid relatedness was studied in 93 CMY-2-producing clinical and commensalE. coliisolates collected from 2006 to 2012 from humans, retail poultry meat, broilers, and dogs. Multilocus sequence typing (MLST), antimicrobial susceptibility testing, and conjugation were performed in conjunction with plasmid replicon typing, plasmid multilocus sequence typing (pMLST), restriction fragment length polymorphism (RFLP), and sequencing of selectedblaCMY-2-harboring plasmids. MLST revealed high strain diversity, with fewE. colilineages occurring in multiple host species and sample types.blaCMY-2was detected on plasmids in 83 (89%) isolates. Most (75%) of the plasmids were conjugative and did not (96%) cotransfer resistance to antimicrobials other than cephalosporins. The main replicon types identified were IncI1-Iγ (55%) and IncK (39%). Isolates from different host species mainly carried distinct plasmid subtypes. Seven of the 18 human isolates harbored IncI1-Iγ/sequence type 2 (ST2), IncI1-Iγ/ST12, or IncK plasmids highly similar to those found among animal isolates, even though highly related human and animal plasmids differed by nonsynonymous single nucleotide polymorphisms (SNPs) or insertion sequence elements. This study clearly demonstrates that the epidemiology of CMY-2 can be understood only by thorough plasmid characterization. To date, the spread of this β-lactam resistance determinant in Denmark is mainly associated with IncK and IncI1-Iγ plasmids that are generally distributed according to host-specific patterns. These baseline data will be useful to assess the consequences of the increasing human exposure to CMY-2-producingE. colivia animal sources.IMPORTANCECMY-2 is the most common plasmid-mediated AmpC β-lactamase inEscherichia coli. This β-lactamase is poorly inhibited by clavulanic acid and confers resistance to cephamycins, third-generation cephalosporins, and aztreonam. Furthermore, resistance to carbapenems has been reported inE. colias a result of production of plasmid-encoded CMY-2 β-lactamase in combination with decreased outer membrane permeability. The gene encoding CMY-2 generally resides on transferable plasmids belonging to different incompatibility groups. The prevalence of CMY-2-mediated cephalosporin resistance inE. colivaries significantly depending on the geographical region and host. This study demonstrates that the epidemiology of CMY-2 can be understood only by thorough plasmid characterization. To date, the spread of this β-lactam resistance determinant in Denmark is mainly associated with IncK and IncI1-Iγ plasmids, which are generally distributed according to host-specific patterns. These data will be useful to assess the consequences of the increasing human exposure to CMY-2-producingE. colivia animal sources.
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Gebre-Yohannes, A., and B. S. Drasar. "Plasmid profiles of antibiotic-resistantShigella dysenteriaetypes 2, 3, 4, 6 and 7 isolated in Ethiopia during 1976–85." Epidemiology and Infection 105, no. 1 (August 1990): 65–72. http://dx.doi.org/10.1017/s0950268800047658.
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SUMMARYPlasmid profile analysis by agarose gel electrophoresis was carried out on 37 drug-resistant strains ofShigella dysenteriaetypes 2, 3, 4, 6 and 7. These strains were collected between 1976 and 1985 in Addis Ababa, Ethiopia.The plasmid profile ofS. dysenteriaetype 2 strains with R-type CSSuT did not show middle-sized plasmids likely to code for CSSuT resistance. All strains contained a large plasmid of about 120 megadaltons (MDa), and a cryptic plasmid of about 2·2 MDa. The plasmid profiles ofS. dysenteriaetype 3 with R-types ACSSuT, SSuT and SSu showed a 4·2 MDa SSu-determinant, which was demonstrated inEscherichia coliK12 recipients resulting from triparental crosses. The ACT determinant inS. dysenteriaetype 3 with R-type ACSSuT is probably chromosomally mediated. Cryptic plasmids of about 3·0 and 2·2 MDa were found in allS. dysenteriaetype 3 isolates. The 4·2 MDa plasmid featured prominently in the plasmid profiles ofS. dysenteriaetypes 4, 6 and 7 with R-types SSuT and SSu. However, this plasmid was not mobilizable by triparental crosses. There was a relative paucity of transferable plasmids in non-Shiga bacillus isolates. However, incompatibility group N plasmids, coding for tetracycline resistance, were detected.
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Schlüter, A., H. Heuer, R. Szczepanowski, L. J. Forney, C. M. Thomas, A. Pühler, and E. M. Top. "The 64 508 bp IncP-1β antibiotic multiresistance plasmid pB10 isolated from a waste-water treatment plant provides evidence for recombination between members of different branches of the IncP-1β group." Microbiology 149, no. 11 (November 1, 2003): 3139–53. http://dx.doi.org/10.1099/mic.0.26570-0.
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The complete 64 508 bp nucleotide sequence of the IncP-1β antibiotic-resistance plasmid pB10, which was isolated from a waste-water treatment plant in Germany and mediates resistance against the antimicrobial agents amoxicillin, streptomycin, sulfonamides and tetracycline and against mercury ions, was determined and analysed. A typical class 1 integron with completely conserved 5′ and 3′ segments is inserted between the tra and trb regions. The two mobile gene cassettes of this integron encode a β-lactamase of the oxacillin-hydrolysing type (Oxa-2) and a gene product of unknown function (OrfE-like), respectively. The pB10-specific gene load present between the replication module (trfA1) and the origin of vegetative replication (oriV) is composed of four class II (Tn3 family) transposable elements: (i) a Tn501-like mercury-resistance (mer) transposon downstream of the trfA1 gene, (ii) a truncated derivative of the widespread streptomycin-resistance transposon Tn5393c, (iii) the insertion sequence element IS1071 and (iv) a Tn1721-like transposon that contains the tetracycline-resistance genes tetA and tetR. A very similar Tn501-like mer transposon is present in the same target site of the IncP-1β degradative plasmid pJP4 and the IncP-1β resistance plasmid R906, suggesting that pB10, R906 and pJP4 are derivatives of a common ancestor. Interestingly, large parts of the predicted pB10 restriction map, except for the tetracycline-resistance determinant, are identical to that of R906. It thus appears that plasmid pB10 acquired as many as five resistance genes via three transposons and one integron, which it may rapidly spread among bacterial populations given its high promiscuity. Comparison of the pB10 backbone DNA sequences with those of other sequenced IncP-1β plasmids reveals a mosaic structure. While the conjugative transfer modules (trb and tra regions) and the replication module are very closely related to the corresponding segments of the IncP-1β resistance plasmid R751 and even more similar to the IncP-1β degradative plasmids pTSA and pADP-1, the stable inheritance operons klcAB–korC and kleAEF are most similar to those of the IncP-1β resistance plasmid pB4, and clearly less similar to the other IncP-1β plasmids. This suggests that IncP-1β plasmids can undergo recombination in the environment, which may enhance plasmid diversity and bacterial adaptability.
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Olukoya, D. K., and O. Oni. "Plasmid profile analysis and antimicrobial susceptibility patterns of shigella isolates from Nigeria." Epidemiology and Infection 105, no. 1 (August 1990): 59–64. http://dx.doi.org/10.1017/s0950268800047646.
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SUMMARYIn an epidemiological survey, plasmid profiles and antimicrobial susceptibility testing of 100 shigella isolates in Lagos, Nigeria was done. All the isolates were sensitive to nalidixic acid, nitrofurantoin and ciprofloxacin. The commonest antimicrobial susceptibility pattern was resistance to ampicillin, colistin sulphate, co-trimoxazole, streptomycin and tetracycline. All but 4 of 100 isolates screened contained one or more plasmids. Plasmid profile analysis distinguished more strains than did antimicrobial susceptibility patterns. A total of 36 isolates was able to transfer resistance plasmids toEscherichia coliK-12 by conjugation. Usingin vitrotransformation, seven isolates transferred resistance. These plasmids specified resistance to tetracycline, streptomycin, sulphonamide, trimethoprim and ampicillin.
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Meng, Miaoling, Yaying Li, and Huaiying Yao. "Plasmid-Mediated Transfer of Antibiotic Resistance Genes in Soil." Antibiotics 11, no. 4 (April 14, 2022): 525. http://dx.doi.org/10.3390/antibiotics11040525.
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Due to selective pressure from the widespread use of antibiotics, antibiotic resistance genes (ARGs) are found in human hosts, plants, and animals and virtually all natural environments. Their migration and transmission in different environmental media are often more harmful than antibiotics themselves. ARGs mainly move between different microorganisms through a variety of mobile genetic elements (MGEs), such as plasmids and phages. The soil environment is regarded as the most microbially active biosphere on the Earth’s surface and is closely related to human activities. With the increase in human activity, soils are becoming increasingly contaminated with antibiotics and ARGs. Soil plasmids play an important role in this process. This paper reviews the current scenario of plasmid-mediated migration and transmission of ARGs in natural environments and under different antibiotic selection pressures, summarizes the current methods of plasmid extraction and analysis, and briefly introduces the mechanism of plasmid splice transfer using the F factor as an example. However, as the global spread of drug-resistant bacteria has increased and the knowledge of MGEs improves, the contribution of soil plasmids to resistance gene transmission needs to be further investigated. The prevalence of multidrug-resistant bacteria has also made the effective prevention of the transmission of resistance genes through the plasmid-bacteria pathway a major research priority.
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Mayer, L. W. "Use of plasmid profiles in epidemiologic surveillance of disease outbreaks and in tracing the transmission of antibiotic resistance." Clinical Microbiology Reviews 1, no. 2 (April 1988): 228–43. http://dx.doi.org/10.1128/cmr.1.2.228.
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Plasmids are circular deoxyribonucleic acid molecules that exist in bacteria, usually independent of the chromosome. The study of plasmids is important to medical microbiology because plasmids can encode genes for antibiotic resistance or virulence factors. Plasmids can also serve as markers of various bacterial strains when a typing system referred to as plasmid profiling, or plasmid fingerprinting is used. In these methods partially purified plasma deoxyribonucleic acid species are separated according to molecular size by agarose gel electrophoresis. In a second procedure, plasmid deoxyribonucleic acid which has been cleaved by restriction endonucleases can be separated by agarose gel electrophoresis and the resulting pattern of fragments can be used to verify the identity of bacterial isolates. Because many species of bacteria contain plasmids, plasmid profile typing has been used to investigate outbreaks of many bacterial diseases and to trace inter- and intra-species spread of antibiotic resistance.
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Stevenson, Cagla, James P. J. Hall, Michael A. Brockhurst, and Ellie Harrison. "Plasmid stability is enhanced by higher-frequency pulses of positive selection." Proceedings of the Royal Society B: Biological Sciences 285, no. 1870 (January 10, 2018): 20172497. http://dx.doi.org/10.1098/rspb.2017.2497.
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Plasmids accelerate bacterial adaptation by sharing ecologically important traits between lineages. However, explaining plasmid stability in bacterial populations is challenging owing to their associated costs. Previous theoretical and experimental studies suggest that pulsed positive selection may explain plasmid stability by favouring gene mobility and promoting compensatory evolution to ameliorate plasmid cost. Here we test how the frequency of pulsed positive selection affected the dynamics of a mercury-resistance plasmid, pQBR103, in experimental populations of Pseudomonas fluorescens SBW25. Plasmid dynamics varied according to the frequency of Hg 2+ positive selection: in the absence of Hg 2+ plasmids declined to low frequency, whereas pulses of Hg 2+ selection allowed plasmids to sweep to high prevalence. Compensatory evolution to ameliorate the cost of plasmid carriage was widespread across the entire range of Hg 2+ selection regimes, including both constant and pulsed Hg 2+ selection. Consistent with theoretical predictions, gene mobility via conjugation appeared to play a greater role in promoting plasmid stability under low-frequency pulses of Hg 2+ selection. However, upon removal of Hg 2+ selection, plasmids which had evolved under low-frequency pulse selective regimes declined over time. Our findings suggest that temporally variable selection environments, such as those created during antibiotic treatments, may help to explain the stability of mobile plasmid-encoded resistance.
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Ling, Julia, and P. Y. Chau. "Incidence of plasmids in multiply-resistant salmonella isolates from diarrhoeal patients in Hong Kong from 1973–82." Epidemiology and Infection 99, no. 2 (October 1987): 307–21. http://dx.doi.org/10.1017/s0950268800067789.
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SUMMARYPlasmids present in multiply-resistant salmonella strains includingSalmonella typhimurium, S. johannesburg, S. wandsworth, S. derby, S. newport, S. londonandS. choleraesuiscausing diarrhoea in patients in Queen Mary Hospital in Hong Kong from 1973–82 were studied. In multiply-resistantS. typhimurium, plasmids belonging to groupsF1me, H1, or H2and plasmids encoding trimethoprim-resistance which were compatible with standard plasmids of testable incompatibility groups were detected. InS. johannesburg, both the ASTCKSu- and ASCKSu- resistant strains which were predominant in two consecutive periods of an outbreak were found to harbour the same plasmid which belonged to the incompatibility group F1me. S. wandsworthstrains isolated from a hospital outbreak in 1980 harboured an identical R-plasmid belonging to group N. A few strains of the other salmonellae showing resistance to multiple antibiotics were found to harbour R-plasmids belonging to groups H1, H2and F1me. The only salmonella of the enteric fever group resistant to ampicillin, chloramphenicol and trimethoprim was anS. paratyphi Bstrain. The resistances were encoded on a plasmid of an unknown incompatibility group. The occurrence and distribution of plasmids in these salmonellae isolated within the 10-year period are discussed.
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Paganini, Julian A., Nienke L. Plantinga, Sergio Arredondo-Alonso, Rob J. L. Willems, and Anita C. Schürch. "Recovering Escherichia coli Plasmids in the Absence of Long-Read Sequencing Data." Microorganisms 9, no. 8 (July 28, 2021): 1613. http://dx.doi.org/10.3390/microorganisms9081613.
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The incidence of infections caused by multidrug-resistant E. coli strains has risen in the past years. Antibiotic resistance in E. coli is often mediated by acquisition and maintenance of plasmids. The study of E. coli plasmid epidemiology and genomics often requires long-read sequencing information, but recently a number of tools that allow plasmid prediction from short-read data have been developed. Here, we reviewed 25 available plasmid prediction tools and categorized them into binary plasmid/chromosome classification tools and plasmid reconstruction tools. We benchmarked six tools (MOB-suite, plasmidSPAdes, gplas, FishingForPlasmids, HyAsP and SCAPP) that aim to reliably reconstruct distinct plasmids, with a special focus on plasmids carrying antibiotic resistance genes (ARGs) such as extended-spectrum beta-lactamase genes. We found that two thirds (n = 425, 66.3%) of all plasmids were correctly reconstructed by at least one of the six tools, with a range of 92 (14.58%) to 317 (50.23%) correctly predicted plasmids. However, the majority of plasmids that carried antibiotic resistance genes (n = 85, 57.8%) could not be completely recovered as distinct plasmids by any of the tools. MOB-suite was the only tool that was able to correctly reconstruct the majority of plasmids (n = 317, 50.23%), and performed best at reconstructing large plasmids (n = 166, 46.37%) and ARG-plasmids (n = 41, 27.9%), but predictions frequently contained chromosome contamination (40%). In contrast, plasmidSPAdes reconstructed the highest fraction of plasmids smaller than 18 kbp (n = 168, 61.54%). Large ARG-plasmids, however, were frequently merged with sequences derived from distinct replicons. Available bioinformatic tools can provide valuable insight into E. coli plasmids, but also have important limitations. This work will serve as a guideline for selecting the most appropriate plasmid reconstruction tool for studies focusing on E. coli plasmids in the absence of long-read sequencing data.
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Feizabadi, Mohammad Mehdi, Sorour Asadi, Maryam Zohari, Sara Gharavi, and Gelavizh Etemadi. "Genetic characterization of high-level gentamicin-resistant strains of Enterococcus faecalis in Iran." Canadian Journal of Microbiology 50, no. 10 (October 1, 2004): 869–72. http://dx.doi.org/10.1139/w04-069.
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The prevalence of resistance to high levels of gentamicin among 182 isolates of Enterococcus faecalis from 2 Iranian hospitals was 42%. Gentamicin resistance was associated with conjugative plasmids (>70 kb) in most strains. Fingerprinting using EcoRI and HindIII showed genetic variation among these plasmids and gave evidence of nosocomial outbreaks and persistence of infection in different wards of the study hospitals, as well as transfer of plasmids between genetically diverse isolates. Using EcoRI, hospital-based specific plasmid fingerprints were detected for the isolates that had previously proved to be unrelated by multilocus enzyme electrophoresis, suggesting the persistence of related plasmids at each hospital, though minor changes in these related plasmids could be detected with HindIII.Key words: Enterococcus faecalis, HLGR, plasmid profiling, plasmid fingerprinting.
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Amyes, S. G. B. "Trimethoprim resistance in commensal bacteria isolated from farm animals." Epidemiology and Infection 98, no. 1 (February 1987): 87–96. http://dx.doi.org/10.1017/s0950268800061744.
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SUMMARYTrimethoprim resistance was examined in faecal bacteria obtained from chickens, sheep, cattle and pigs. The incidence of trimethoprim resistance in porcine strains was 17% (157/922) and, whereas 15·8% (146/922) of these bacteria were highly resistant, only 4% (37/922) of the isolates possessed trimethoprim resistance plasmids. Highly resistant porcine strains were obtained from 44% of the pig farms (41/93) but transferable trimethoprim resistance was found in isolates from 11% (10/93) of the farms. There was an association between the carriage of trimethoprim resistance plasmids and certain farms. Most of the resistance plasmids were not identical with those found in human clinical bacteria but one porcine plasmid was the same as the most ubiquitous trimethoprim resistance plasmid in Edinburgh.
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Magrini, Vincent, Chad Creighton, David White, Patricia L. Hartzell, and Philip Youderian. "The aadA Gene of Plasmid R100 Confers Resistance to Spectinomycin and Streptomycin in Myxococcus xanthus." Journal of Bacteriology 180, no. 24 (December 15, 1998): 6757–60. http://dx.doi.org/10.1128/jb.180.24.6757-6760.1998.
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ABSTRACT Plasmids with the aadA gene from plasmid R100, which confers resistance to the aminoglycosides spectinomycin and streptomycin in Escherchia coli, can be introduced into wild-type Myxococcus xanthus, strain DK1622, by electroporation. Recombinant M. xanthus strains with integrated plasmids carrying the aadA gene acquire resistance to high levels of these antibiotics. Selection foraadA in M. xanthus can be carried out independently of, or simultaneously with, selection for resistance to kanamycin. The kinds and frequencies of recombination events observed between integrative plasmids with aadA and the M. xanthus chromosome are similar to those observed after the transformation of yeast. Cleavage of integrative plasmid DNA at a site adjacent to a region of homology between the plasmid and the M. xanthus genome favors the targeted disruption ofM. xanthus genes by allele replacement.
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Penttinen, Reetta, Cindy Given, and Matti Jalasvuori. "Indirect Selection against Antibiotic Resistance via Specialized Plasmid-Dependent Bacteriophages." Microorganisms 9, no. 2 (January 29, 2021): 280. http://dx.doi.org/10.3390/microorganisms9020280.
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Antibiotic resistance genes of important Gram-negative bacterial pathogens are residing in mobile genetic elements such as conjugative plasmids. These elements rapidly disperse between cells when antibiotics are present and hence our continuous use of antimicrobials selects for elements that often harbor multiple resistance genes. Plasmid-dependent (or male-specific or, in some cases, pilus-dependent) bacteriophages are bacterial viruses that infect specifically bacteria that carry certain plasmids. The introduction of these specialized phages into a plasmid-abundant bacterial community has many beneficial effects from an anthropocentric viewpoint: the majority of the plasmids are lost while the remaining plasmids acquire mutations that make them untransferable between pathogens. Recently, bacteriophage-based therapies have become a more acceptable choice to treat multi-resistant bacterial infections. Accordingly, there is a possibility to utilize these specialized phages, which are not dependent on any particular pathogenic species or strain but rather on the resistance-providing elements, in order to improve or enlengthen the lifespan of conventional antibiotic approaches. Here, we take a snapshot of the current knowledge of plasmid-dependent bacteriophages.
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Waltman II, W. Douglas, Emmett B. Shotts, and Richard E. Wooley. "Development and Transfer of Plasmid-Mediated Antimicrobial Resistance in Edwardsiella ictaluri." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 7 (July 1, 1989): 1114–17. http://dx.doi.org/10.1139/f89-144.
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Edwardsiella ictaluri were found to develop and transfer plasmid-mediated antimicrobial resistance. All isolates tested were found to receive resistance(R)-plasmids at frequencies ranging from 10−3 to 10−6. The antimicrobials to which E. ictaluri became resistant included tetracycline and Romet, the only two antibiotics cleared for use in channel catfish (Ictalurus punctatus) culture. The frequency of plasmid transfer appeared to be temperature related, with higher frequencies at 30 °C than at 20 or 37 °C. E. ictaluri having received an R-plasmid was shown to transfer the plasmid to Escherichia coli and Yersinia ruckeri at fairly high frequencies.