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Articles de revues sur le sujet "Klebsiella pneumoniae Strain PB12"
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Mandal, Amit K., Ipsita K. Sen, Prasenjit Maity, Sourav Chattopadhyay, Ranadhir Chakraborty, Somenath Roy et Syed S. Islam. « Structural elucidation and biological studies of a novel exopolysaccaride from Klebsiella pneumoniae PB12 ». International Journal of Biological Macromolecules 79 (août 2015) : 413–22. http://dx.doi.org/10.1016/j.ijbiomac.2015.04.077.
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Yan, Kai, Changfu Li, Weiyu Wang, Juan Guo et Haifeng Wang. « The Molecular Identification and Comprehensive Analysis of Klebsiella pneumoniae Isolated from Industrial Wastewater ». Separations 11, no 4 (17 avril 2024) : 121. http://dx.doi.org/10.3390/separations11040121.
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Industrial wastewater typically contains many organic and inorganic pollutants and is also contaminated by various microorganisms. Microbial species in industrial wastewater have not been extensively investigated. In this experiment, a Klebsiella pneumoniae strain was isolated for the first time from industrial wastewater containing a high concentration of sulfate and phosphate. Mass spectrometry, genetic analysis, and biochemical identification were conducted to understand the genetic and biochemical characteristics of this Klebsiella pneumoniae strain recovered from industrial wastewater. Growth experiments revealed that it exhibited an excellent growth rate in nutrient broth. Further analyses showed that the strain was sensitive to most antibiotics but resistant to chloramphenicol and nitrofurantoin. It also exhibited significant resistance to piperacillin/tazobactam and cefotaxime/clavulanic acid. Resistance gene experiments indicated the presence of gyrA, OqxB, and ParC genes associated with antibiotic resistance in the isolated Klebsiella pneumoniae strain. Proteomics uncovered the following three proteins related to drug resistance: the multi-drug resistant outer membrane protein MdtQ, the multi-drug resistant secretion protein, and the modulator of drug activity B, which are coexistent in Klebsiella pneumoniae. Proteomics and bioinformatics analyses further analyzed the protein composition and functional enrichment of Klebsiella pneumoniae. The isolation of Klebsiella pneumoniae from a high concentration in sulfate and phosphate industrial wastewater provides a new direction for further research on the characteristics and drug resistance traits of industrial wastewater microorganisms and the potential risks they may pose when released into the environment.
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Aminah, Aminah, Citra Trisna et Dewi Lokida. « Deteksi Molekuler Klebsiella pneumoniae K1, K2, dan K5 yang Diisolasi dari Berbagai Spesimen Klinis ». Journal of Medical Laboratory Research 2, no 1 (9 décembre 2023) : 1–6. http://dx.doi.org/10.36743/jomlr.v2i1.633.
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Klebsiella pneumoniae adalah salah satu penyebab utama healthcare-associated infections dengan tingkat multidrug resistance (MDR) tinggi, terutama klon penghasil extended-spectrum beta-lactamase (ESBL) dan carbapenemase (CP). Serotipe kapsul Klebsiella pneumoniae sangat bervariasi sesuai tingkat resistensinya terhadap serum dengan K1, K2, dan K5 menjadi penanda strain hipervirulen yang berbeda dari Klebsiella pneumoniae klasik dalam masyarakat pada umumnya. Penelitian ini bertujuan untuk mengaplikasikan teknik polymerase chain reaction (PCR) untuk mendeteksi genotipe kapsul K1, K2, dan K5 Klebsiella pneumoniae asal pasien Rumah Sakit Umum (RSU) Kabupaten Tangerang. Isolasi dan uji resistensi dilakukan oleh Laboratorium RSU Kabupaten Tangerang. Konfirmasi spesies K. pneumoniae dan deteksi genotipe kapsul dengan metode PCR dilakukan di Laboratorium Molekuler Poltekkes Kemenkes Banten. Sebanyak delapan isolat (26,7%) merupakan K. pneumoniae resistan Carbapenem dan 11 (36,7%) penghasil extended spectrum beta-lactamase (ESBL). Dari total 31 sampel yang diperoleh, hanya satu isolat yang tidak dapat dikonfirmasi. Seluruh isolat yang terkonfirmasi K. pneumoniae diproses untuk tahap selanjutnya. Pemeriksaan PCR menggunakan primer untuk mendeteksi genotipe kapsul K1, K2, dan K5 menunjukkan hanya satu isolat (3,3%) yang diduga merupakan strain hipervirulen dengan genotipe kapsul K2. Tidak ada genotipe K1 dan K5 pada semua isolat yang diperiksa.
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Padilla, Emma, Diana Alonso, Antonio Doménech-Sánchez, Cristina Gomez, José Luis Pérez, Sebastián Albertí et Nuria Borrell. « Effect of Porins and Plasmid-Mediated AmpC β-Lactamases on the Efficacy of β-Lactams in Rat Pneumonia Caused by Klebsiella pneumoniae ». Antimicrobial Agents and Chemotherapy 50, no 6 (juin 2006) : 2258–60. http://dx.doi.org/10.1128/aac.01513-05.
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ABSTRACT The in vivo activities of imipenem, meropenem, and cefepime were studied in a model of rat pneumonia caused by a plasmid-mediated AmpC β-lactamase ACT-1-producing Klebsiella pneumoniae strain (K. pneumoniae strain 12) and a derivative porin-deficient mutant (K. pneumoniae strain 12dp). No differences between these activities were seen with K. pneumoniae 12. Only meropenem showed an activity slightly better than that of imipenem with K. pneumoniae 12dp.
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Crespo-Yanez, Xenia, et Imen Ayadi. « The AI516 and AI523 antibodies recognize the Klebsiella pneumoniae KpGe strain by flow cytometry ». Antibody Reports 5, no 1 (3 mars 2022) : e682. http://dx.doi.org/10.24450/journals/abrep.2022.e682.
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The recombinant antibodies AE516 and AI523 bind to the surface of the Klebsiella pneumoniae KpGe strain, as detected by flow cytometry. They do not bind to a K. pneumoniae strain defective in O-antigen synthesis.
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Martins, Paula Fabiane, Camila Ortiz Martinez, Giselle de Carvalho, Paulo Irajara Borba Carneiro, Ricardo Antunes Azevedo, Sônia Alvim Veiga Pileggi, Itamar Soares de Melo et Marcos Pileggi. « Selection of microorganisms degrading S-Metolachlor herbicide ». Brazilian Archives of Biology and Technology 50, no 1 (janvier 2007) : 153–59. http://dx.doi.org/10.1590/s1516-89132007000100019.
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The aim of this work was to study herbicide degradation through selected microorganisms from humus and soil subjected to different plantation systems. The following bacterial species were identified: Klebsiella pneumoniae pneumoniae GC s.B strain 1, Pseudomonas alcaligenes, Enterobacter aerogenes GC s.A and Klebsiella pneumoniae pneumoniae GC s.B strain 2. Growth studies yet suggested the possibility of a very long lag phase. Although, culture with the herbicide presented biofilm formation and there were color changes in the herbicide that could have interfered with the espectrophotometry readings. After 5 days of incubation at 35ºC, the difference in the concentration of herbicide was 14.42% on average and after 10 days, 35.01%.
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Chen, Kong, Meagan Goodwin, Jeremy McAleer, Nikki Nguyen, Emily Way et Jay Kolls. « Recombinant outer membrane protein : a potential candidate for Th17 based vaccine against Klebsiella pneumoniae. (VAC7P.967) ». Journal of Immunology 192, no 1_Supplement (1 mai 2014) : 141.12. http://dx.doi.org/10.4049/jimmunol.192.supp.141.12.
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Abstract Bacterial pneumonia is a leading cause of mortality and one major pathogen associated with this disease is Klebsiella pneumoniae. Recently, the emergence of antibiotic resistant strains demands an effective vaccine against these bacteria. We have previously shown that intranasal immunization with heat-killed K. pneumoniae or crude outer membrane proteins isolated from K. pneumoniae induced antigen specific Th17 responses and these Th17 cells conferred serotype independent protection against various clinical isolates of K. pneumoniae including the recently described multidrug resistant New Delhi Metallo-beta-lactamase-1 strain. To develop a clinically relevant Klebsiella vaccine, we cloned single OMP genes by PCR from K. pneumoniae and successfully expressed one recombinant outer membrane protein, OmpX, in the BL21 E. coli strain. The purified recombinant OmpX was recognized by Klebsiella immune serum by direct ELISA and also recognized by Th17 cells from Klebsiella immunized mice. In vivo, intranasal immunization of the purified OmpX induced robust mucosal Th17 responses and left IL-17 producing gamma-delta T cells unaffected. Ongoing work will determine whether these Th17 responses will result in serotype independent protection against live bacterial challenge including the multidrug resistant strains.
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Kang, Fuqiang, Zili Chai, Beiping Li, Mingda Hu, Zilong Yang, Xia Wang, Wenting Liu, Hongguang Ren, Yuan Jin et Junjie Yue. « Characterization and Diversity of Klebsiella pneumoniae Prophages ». International Journal of Molecular Sciences 24, no 11 (23 mai 2023) : 9116. http://dx.doi.org/10.3390/ijms24119116.
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Klebsiella pneumoniae is a common human commensal and opportunistic pathogen. In recent years, the clinical isolation and resistance rates of K. pneumoniae have shown a yearly increase, leading to a special interest in mobile genetic elements. Prophages are a representative class of mobile genetic elements that can carry host-friendly genes, transfer horizontally between strains, and coevolve with the host’s genome. In this study, we identified 15,946 prophages from the genomes of 1437 fully assembled K. pneumoniae deposited in the NCBI database, with 9755 prophages on chromosomes and 6191 prophages on plasmids. We found prophages to be notably diverse and widely disseminated in the K. pneumoniae genomes. The K. pneumoniae prophages encoded multiple putative virulence factors and antibiotic resistance genes. The comparison of strain types with prophage types suggests that the two may be related. The differences in GC content between the same type of prophages and the genomic region in which they were located indicates the alien properties of the prophages. The overall distribution of GC content suggests that prophages integrated on chromosomes and plasmids may have different evolutionary characteristics. These results suggest a high prevalence of prophages in the K. pneumoniae genome and highlight the effect of prophages on strain characterization.
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Brisse, Sylvain, Virginie Passet et Patrick A. D. Grimont. « Description of Klebsiella quasipneumoniae sp. nov., isolated from human infections, with two subspecies, Klebsiella quasipneumoniae subsp. quasipneumoniae subsp. nov. and Klebsiella quasipneumoniae subsp. similipneumoniae subsp. nov., and demonstration that Klebsiella singaporensis is a junior heterotypic synonym of Klebsiella variicola ». International Journal of Systematic and Evolutionary Microbiology 64, Pt_9 (1 septembre 2014) : 3146–52. http://dx.doi.org/10.1099/ijs.0.062737-0.
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Strains previously classified as members of Klebsiella pneumoniae phylogroups KpI, KpII-A, KpII-B and KpIII were characterized by 16S rRNA (rrs) gene sequencing, multilocus sequence analysis based on rpoB, fusA, gapA, gyrA and leuS genes, average nucleotide identity and biochemical characteristics. Phylogenetic analysis demonstrated that KpI and KpIII corresponded to K. pneumoniae and Klebsiella variicola , respectively, whereas KpII-A and KpII-B formed two well-demarcated sequence clusters distinct from other members of the genus Klebsiella . Average nucleotide identity between KpII-A and KpII-B was 96.4 %, whereas values lower than 94 % were obtained for both groups when compared with K. pneumoniae and K. variicola . Biochemical properties differentiated KpII-A, KpII-B, K. pneumoniae and K. variicola , with acid production from adonitol and l-sorbose and ability to use 3-phenylproprionate, 5-keto-d-gluconate and tricarballylic acid as sole carbon sources being particularly useful. Based on their genetic and phenotypic characteristics, we propose the names Klebsiella quasipneumoniae subsp. quasipneumoniae subsp. nov. and K. quasipneumoniae subsp. similipneumoniae subsp. nov. for strains of KpII-A and KpII-B, respectively. The type strain of K. quasipneumoniae sp. nov. and of K. quasipneumoniae subsp. quasipneumoniae subsp. nov. is 01A030T ( = SB11T = CIP 110771T = DSM 28211T). The type strain of K. quasipneumoniae subsp. similipneumoniae subsp. nov. is 07A044T ( = SB30T = CIP 110770T = DSM 28212T). Both strains were isolated from human blood cultures. This work also showed that Klebsiella singaporensis is a junior heterotypic synonym of K. variicola .
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Usman, Nazeef Idris. « Phenotypic characterization, detection of virulence factors, and antibacterial susceptibility profile of clinical isolates of Klebsiella pneumoniae ». Gadau Journal of Pure and Allied Sciences 1, no 2 (2 octobre 2022) : 121–32. http://dx.doi.org/10.54117/gjpas.v1i2.11.
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Klebsiella pneumoniae has been one of the most occurring bacteria in clinical samples causing community-acquired and nosocomial infections. It has been developing resistance to most antimicrobial agents. These have increased the pathogenicity and the chance for the evolvement of more invasive K. pneumoniae. The study was aimed at the identification and detection of Klebsiella pneumoniae from clinical samples. Some selected virulence factors were detected and the antibacterial susceptibility profile of the isolates was conducted. The incubation period, infective dose, and mortality rate of K.pneumoniae were measured using Baggs albino rats (BALB/c) strain. The isolation and identification of 56 Klebsiella pneumoniae from 223 clinical samples were made. Out of 56 K. pneumoniae isolates, all manifested mucoid phenotype, 44(78.6%) capsule antigen and 13(23.2%) Siderophore. The antimicrobial test conducted identified Zinacef 51(91.1%), Rocephin 50 (89.3%), and Ampiclox 50 (91.1%) as the most resistant. Ciprofloxacin 49 (87.5%), chloramphenicol 35(62.5%), Gentamycin 32(57.1%), and Amoxicillin 28 (50%) were the most susceptible to Klebsiella pneumoniae. The mouse lethality test shows that K. pneumoniae hypermucoviscous strain can cause 41.7% lethality and 66.7% mortality in Baggs Albino rats. Meanwhile an infection dose 105cfu/ml, 107cfu/ml and 109cfu/ml produced an incubation period of 9 days, 7days and 5days. The chi-square test shows no significant association between the isolate and the gender of the patients, but there is a significant association between the samples and isolates identified p <0.05. Likewise, the association between mucoid phenotype, capsule antigen, siderophore, and the type of infection is significant (p<0.05). It is finally concluded that K. pneumoniae is the second most prevailing bacterium causing community-acquired infection the resistant pattern recorded identified the test bacteria as a multidrug-resistant strain and manifestation of the virulent factor depends on the type and site of infection caused by the K. pneumoniae.
Thèses sur le sujet "Klebsiella pneumoniae Strain PB12"
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Mandal, Amit Kumar. « Exploring physiology of an exopolysaccharide(EPS) producing facultatively oligotrophic bacterium klebsileea pneumoniae pb12 with special emphasis on structure -function analysis of EPS ». Thesis, University of North Bengal, 2015. http://ir.nbu.ac.in/hdl.handle.net/123456789/2755.
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Kornacker, Michael Gilbert. « Analysis of pullulanase secretion from Klebsiella pneumoniae strain K21 ». Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/34437.
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Strains of the Gram-negative bacterium Klebsiella pneumoniae secrete pullulanase, a maltose-inducible starch debranching enzyme that exists as a cell surface bound intermediate. Three classes of secretion mutants were obtained by transposon In 10 mutagenesis. Class I and class III mutants carry Tn10 insertions in pullulanase secretion genes. Class II mutants carry insertions in regulatory loci that are required for the high level expression of pullulanase and other maltose-inducible genes (the maltose regulon). One such locus appears to correspond to a previously unknown locus. The phenotypes of the secretion mutants and the analysis of E.coli expressing pullulanase and/or cloned pullulanase secretion genes suggest that pullulanase secretion functions are involved in translocating pullulanase across the outer membrane and in releasing it from the cell surface. Most if not all pullulanase secretion genes are located to both sides of the structural gene for pullulanase (pu1A). Pullulanase was found to be a lipoprotein. Surprisingly, secreted pullulanase also carried lipid. However, strain K21 differed from other strains of Klebsiella pneumoniae by its ability to secrete not only acylated pullulanase but also a second, unacylated form of pullulanase. Strain K21 is also unusual because of its ability to secrete most pullulanase during logarithmic growth. This pullulanase corresponds to the unacylated pullulanase, with the remaining secreted pullulanase being acylated and secreted during stationary phase, as is the case for most or all pullulanase of other strains of Klebsiella pneumoniae. Strain K21 is also unusual because of the high level expression of the maltose regulon, including pulA, in the absence of maltose. This property, including the unusual features described above, may be a consequence of the selection of strain K21 for high level commercial production of pullulanase. Models for pullulanase secretion are discussed and approaches towards increasing the efficiency of commercial pullulanase production by strain K21 are outlined.
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Lespinat, Paul Antoine. « Métabolisme bactérien de l'hydrogène : aspects physiologiques et enzymologiques ». Grenoble 1, 1988. http://www.theses.fr/1988GRE10061.
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Wu, Po Kuan, et 吳柏寬. « Characterization of Fucosyltransferase gene and virulence gene in virulent Klebsiella pneumoniae strain ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/65877894199437177672.
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碩士長庚大學
生物醫學研究所
99
Klebsiella pneumoniae (KP), an enterobacterium, usually causes urinary tract infection or pneumonia. Recently, severe liver abscess caused by KP has been observed in Taiwan, especially in patients with diabetes mellitus, but the cases of Klebsiella-liver abscess are very few in other countries. How the bacteria cause liver abscess is not clear. Previously, our laboratory analysis of the KP capsule by capillary HPLC revealed that the virulent KP (KP5) capsule contained fucose while UTI strain (KP3) did not have. Further analysis with anti-Lewis antibodies manifested that the capsule contained Lewis antigens while KP3 and E.coli 7E1 (include CPS region sequence) did not. The purpose of this project is to find the fucosyltransfersae gene that is responsible for attaching fucose to sugar backbone to form Lewis antigen. We used known H.pylori fucosyltransferase (FucT) gene sequence to design primer (F1,3 primer & FR primer). The amplified fragments that appeared on KP5 and KP95 but not on KP3 were chosen for cloning. Interesting, we find the one fragment is specific for liver abscess KP strains and not in UTI strains. Another one fragment is specific for gmd-positive KP strains but not in gmd-negative KP strains. This gmd associated gene is a putative fucosyltransferase gene in KP. E.coli 7E1 Transformed with this gene can express Lewis Antigen (Sialyl-Lewis-x and Lewis-b)
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Yu, Kuan Fang, et 於冠芳. « Promoter studies of the cps gene cluster in a virulent klebsiella pneumoniae strain ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/53200149472273419560.
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碩士長庚大學
生物醫學研究所
97
Abstract Klebsiella pneumoniae is a normal flora present in human intestinal tract, but will cause disease in immunocompromised patients. Primary pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae is an emerging infectious disease especially in diabetic patients. The effect of glucose concentrations on the promoter of capsular polysaccharide (cps) gene region was investigated. The putative promoters of the Kp5, a virulent strain, were cloned into a plasmid containing -galactosidase reporter system. Seven putative promoter regions, designated A, B, C, D, E, F, G, were cloned and the -galactosidase activity assays suggested that the regions of galF to orf2（A）, orf2 to wzi（B）, wzi to wza（G）, and rfbp to gnd（E）have promoter activities. The promoter B in the upstream region of wzi showed higher promoter activity than others, enhanced by glucose addition, and wzi mRNA expression was elevated at the same time. To study transcription regulation of gene wzi, we observed that the activity of promoter G was elevated under the influence of promoter B and wzi gene. The over all activity of promoter G was increased under high glucose condition, however the gmd and wcaG mRNA expression was decreased, suggesting that the decrease of gmd and wcaG mRNA expression might be due to the feedback inhibition of the increased fucose final product. We also observed that Kp5 increased its growth rate at high glucose condition. In summary, our results suggested that high glucose condition, such as in the case of diabetes enhanced bacterial growth and the immunocompromised state of the DM patients were the major cause of diabetic patients with high susceptibility to Klebsiella pneumoniae infection.
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Chen, Chia Yi, et 陳佳怡. « Characterization of Virulence Factors, kpv1 and terD in a Klebsiella Pneumoniae Strain KP5 ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/78297157908713256653.
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碩士長庚大學
生物醫學研究所
101
Klebsiella pneumonia ( KP ) is an opportunistic bacterium and it can cause many clinical symptoms, including pyogenic liver abscess ( LA )、urinary tract infection ( UTI ) and endophthalmitis, with a high rate of mortality especially in diabetic patients. Some clinically isolated KPs harbor a large plasmid about 200 kb in size. The plasmid contains conserved sequences, such as kpv1 and terD. By using polymerase chain reaction ( PCR ), these two genes were found only to exist in highly virulent LA strains including KP5 which induced high fatality in infected mice, where as the UTI infections did not kill mice. The purpose of this study is to examine whether the kpv1 and terD genes are associated with KP virulence. The kpv1 and terD genes were cloned to expression vectors, pET-30a and pET-30b respectively. The recombinant plasmids were transformed to E. coli 7E1 strain which was previously shown to contain the entire KP5 capsular gene cluster and display the mucoid phenotype as KP strain. This E. coli 7E1/pET-30a::kpv1 or E. coli 7E1/pET30-b::terD was introduced into mice by tail vein injection. The survival of the infected mice was monitored for 15 days. No fatality in infected mice was observed. The results suggest that introducing only one gene to E. coli 7E1 may not confer pathogenicity, and it may need other unknown genes or factors to exhibit fatality in mice. I wanted to construct KP5 mutants for kpv1 and terD in addition and compare the virulence in mice between the wild type and the mutant strains. But to this study, I was unable to select successful mutants indicating that the technique I used needed improvement. On the other hand pKPV was purified and transformed to KP3, and examined for it’s virulence in mice by tail vein injection. The results showed that the mortality of KP3/pKPV was very similar to KP5 that the mice all died within three days. I used PCR to check the purified pKPV and detected small amount of chromosome material in the prepared plasmid. Attempts to remove the chromosome material from the plasmid preparation were not successful. It might be that both pKPV and chromosome material were transformed into KP3 to yield a KP5. For primer design, the sequence of NTUH-K2044 chromosome and plasmid pK2044 was used. Both NTUH-K2044 and KP5 are the K1 serotype, we therefore considered these two strains were very similar. We considered the size of pKPV should be close to pk2044.
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Wu, Meng-Chuan, et 吳孟娟. « Isolation of Genes Involved in Biofilm formation of a Klebsiella pneumoniae strain causing pyogenic liver abscess ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/64054634758151221664.
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博士國立臺灣大學
微生物學研究所
100
Background: Community-acquired pyogenic liver abscess (PLA) complicated with meningitis and endophthalmitis caused by Klebsiella pneumoniae is an emerging infectious disease. To investigate the mechanisms and effects of biofilm formation of K. pneumoniae causing PLA, microtiter plate assays were used to determine the levels of biofilm formed by K. pneumoniae clinical isolates and to screen for biofilm-altered mutants from a transposon mutant library of a K. pneumoniae PLA-associated strain. Methodology/Principal Findings: The biofilm formation of K. pneumoniae was examined by microtiter plate assay. Higher levels of biofilm formation were demonstrated by K. pneumoniae strains associated with PLA. A total of 23 biofilm-decreased mutants and 4 biofilm-increased mutants were identified. Among these mutants, a biofilm-decreased treC mutant displayed less mucoviscosity and produced less capsular polysaccharide (CPS), whereas a biofilm-increased sugE mutant displayed higher mucoviscosity and produced more CPS. The biofilm phenotypes of treC and sugE mutants also were confirmed by glass slide culture. Deletion of treC, which encodes trehalose-6-phosphate hydrolase, impaired bacterial trehalose utilization. Addition of glucose to the culture medium restored the capsule production and biofilm formation in the treC mutant. Transcriptional profile analysis suggested that the increase of CPS production in ΔsugE may reflect elevated cps gene expression (upregulated through rmpA) in combination with increased treC expression. In vivo competition assays demonstrated that the treC mutant strain was attenuated in competitiveness during intragastric infection in mice. Conclusions/Significance: We have identified 25 genes important for biofilm formation in a K. pneumoniae PLA strain using microtiter plate assay and confirmed by slide cultures. Among these genes, treC and sugE affect biofilm formation by modulating CPS production. The importance of treC in gastrointestinal tract colonization suggests that biofilm formation contributes to the establishment and persistence of K. pneumoniae infection.
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Chen, Fei-hsu, et 陳飛旭. « Analysis of Conserved Genes in Klebsiella Pneumoniae Capsular Gene Cluster of K20 Strain and Its Effect on Virulence ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/qsjc3s.
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碩士國防醫學院
微生物及免疫學研究所
102
Capsular polysaccharide is one of the most important virulent factors in K. pneumoniae. Previous studies indicate that CPS gene clusters of diverse K-serotype K. pneumoniae strains contain six conserved genes with the order of galF, acidPPc, wzi, wza, wzb and wzc at 5’ end. Other study indicated that Wzi involved in attachment of the repeat unit of capsular polysaccharide to the outer membrane. As the uniqueness of wzi to their capsular serotypes in K. pneumoniae, serotype-specific primer from wzi could be designed according to their K serotypes. Further analysis showed that the amino acid sequence of Wzi in several K-serotypes, varies with each K-serotype. The interplay between these proteins and capsular polysaccharide as well as its virulence could be further explored. Reference to the capsule (CPS) gene clusters in group 1 E. coli K30 serotype, whose infrastructure is similar to K20 serotype of K. pneumoniae, give us some hints about gene function of individual genes in K20 CPS cluster. Its actual virulent effect in K. pneumoniae caused by these individual genes is not still familiar. In this study, individual knockout of the above 6 genes from a highly virulent K. pneumonia K20 serotype strain were performed. wzi gene exchanged from K20 to K1 would also be attempted. Serotype change of each successful clones would be carried out by serum agglutination. Virulence of each mutant would be assessed through serum killing, neutrophil phagocytosis and mouse lethality assay. Comparison to the parental strain (mucoid, serum-sensitive, and phagocytosis-resistant, LD50=102 CFU), both LD50 of galF and acidPPc mutants; wzi mutant and wza, wzb and wzc mutants decreased 10 folds, 102 folds and more than 105 folds correspondingly. For low virulent gene- galF and acidPPc, there were no obvious change in its colony morphology, positive agglutination in K20 serum and sensitive in phagocytosis among galF and acidPPc mutants. Lack of making glucose by galF would not change serum killing. Only acidPPc mutant become serum resistant in serum killing implicating that AcidPPc affect LPS function and decrease efficiency of serum killing. High virulent genes- wza, wzb or wzc, wza, wzb or wzc mutants showed smaller colonies, negative agglutination in K20 serum, sensitive in serum killing and highly sensitive in phagocytosis were demonstrated. Without capsule repeat unit assembling protein and transporter for synthesis may be account for highly susceptible in phagocytosis. Moderate virulent gene-wzi, wzi mutant was positive in K20 serum agglutination, more susceptible in serum killing and susceptible in phagocytosis. As its capsule become less firm, a tough pellet in centrifugal test and phagocytosis-resistance were easily obtained. Loosing ability for repeat units to anchor tightly in outer membrane leading a loose capsule was attributed to the above results. After complementation K1 wzi to wzi mutant, weak K20 serum agglutination was examined, anti-serum killing and anti- phagocytosis was comparable to that in parental strain. This may be explained by fixing the repeat unit assembling in capsule resulting to no more defective structure in capsule. In conclusion, the conserved genes of capsule gene cluster in K. pneumoniae have impact in virulence in mice model. The intensity of change in colony morphology, serum agglutination, anti-serum killing and anti-phagocytosis varies among individual genes in this CPS cluster. Relatively, wzi could cause the least effect in affecting serum specificity.
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Ni, Chung-En, et 倪崇恩. « Transcriptome profiling reveals the underlying mechanisms of stress responses of a high-virulence and drug-resistance Klebsiella pneumoniae strain ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/t22ajc.
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碩士國立陽明大學
生物醫學資訊研究所
106
Carbapenem-resistant Enterobacteriaceae (CRE) are emerging life-threating pathogens which can cause serious infectious diseases. So far, little is known about how certain strains could be both drug-resistant (DRE) and hyper-virulent (HV). In this project, we set out to build a model that can facilitate the systematic study of the underlying mechanisms of DRE and HV of CRE. A hyper-virulent (HV) and multi-drug resistant (MDR) Klebsiella pneumoniae (KP) isolate, TVGHCRE225, which belongs to CRE and can also resist two commonly used anti-KP drugs, colistin, and tigecycline was taken for transcriptome profiling under the challenges of different antibiotics. TVGHCRE225 was treated with tigecycline and colistin, respectively, and samples were collected at the mid-log phase and at the log phase. RNA-Seq was performed to acquire the transcriptome profiling data of those samples. Rockhopper was used to analyze the RNA-seq data. Reads per kilobase per million mapped reads (RPKM) for each TVGHCRE225 gene were estimated, and operons were predicted through clustering co-expressed genes that were physically close to each other on the TVGHCRE225 genome. Differentially expressed genes (DEGs), as well as differentially regulatory operons (DROs), were functionally annotated using a gene set enrichment analysis approach. Our results suggest that TVGHCRE225 present the similar physiological mechanisms under the tigecycline and colistin treatments. At the log phase, TVGHCRE225 changed to the anaerobic respiration, reduced energy comsumption, to reduce the communication with the outside world, and also, up-regulated the function about the virulence and biofilm formation to adapt to the environment change. We also found that certain operons revealed structural changes as fewer genes in them were transcribed at the treatments of tigecycline and colistin. The implicated biological processes of such operons include cell division, cell cycle, cell wall biogenesis/degradation, regulation of cell shape, etc.
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Yang, Shu-Li, et 楊淑理. « Identification of Genes Present Specifically in a Virulent Strain of Klebsiella pneumoniae-Sequence and Expression Analysis of KvgASQR Gene Cluster ». Thesis, 2000. http://ndltd.ncl.edu.tw/handle/02274953831171245622.
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碩士國立清華大學
生命科學系
88
Klebsiella pneumoniae is a common cause of septicemia and urinary tract infection in immunocompromised patients. In order to identify virulence-associated genes in the bacterium, a PCR-supported genomic subtractive hybridization was employed. Analysis of 30 subtracted DNA clones has revealed 21 distinct nucleotide sequences. Among them, eleven clones were found to be previously identified genes, including those encode the transposase of Tn3926, the capsule polysaccharide synthetic enzymes, an alcohol dehydrogenase and SeqA protein. Three sequences were found to be the homolog of the virulence regulator bvgAS, a two-component signal transduction system of Bordetella pertussis. The rest of the clones, representing 15 distinct sequences, did not exhibit homology with any known genes. Southern blotting analysis using each of these anonymous sequences as a probe has shown that the distribution of these sequences varied greatly in K. pneumoniae clinical isolates, reflecting the heterogeneous nature of K. pneumoniae population. The entire region of the bvg-like genes was subsequently isolated and designated kvg (klebsiella virulence gene). The gene cluster was found to be organized in an unusual structure of kvgASQR, in which KvgS is the sensory histidine kinase, KvgA and KvgR are two highly homologous transcription factors, and KvgQ is likely to be a membrane protein of unknown function. The kvg genes were found to present in approximately 13% of all bacteriemic isolates of K. pneumoniae. By using luxAB as the reporter, we have found that the expression of kvgASQ are activated in the presence of divalent cation chelators, and H2O2. The result suggests that the kvg genes play a role in pathogenesis of K. pneumoniae. Introduction：
Actes de conférences sur le sujet "Klebsiella pneumoniae Strain PB12"
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Alam, J. M., H. Ahmed, K. Garnepudi, R. B. Kesavan, H. Thai, G. Jayaraman, K. Oakson, E. Young et S. T. Sarva. « Severe Metastatic Klebsiella Pneumoniae Infection Caused by Hypervirulent Strain ST23 in a 38 Year Old with Hepatic Abscess, Septic Thrombophlebitis and Septic Embolism ». Dans American Thoracic Society 2021 International Conference, May 14-19, 2021 - San Diego, CA. American Thoracic Society, 2021. http://dx.doi.org/10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a2947.
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