Genetic and phenotypic characterization of klebsiella pneumoniae isolated from Matang mangrove estuary Malaysia / Anis Barati

• 第一著者: Anis, Barati
• フォーマット: 学位論文
• 出版事項: 2014
• 主題: Q Science (General); QR Microbiology

The genus Klebsiella is ubiquitous in nature. The environmental sources of this bacterium include soil, surface waters, plants, sewage, industrial effluents and mammalian gastrointestinal tract. K. pneumoniae is an opportunistic Gram-negative bacterium and is an emergent multidrug resistant strain with potential virulence to human. In this study, phenotypic and genotypic methods were used to screen for potentially pathogenic K. pneumoniae isolated from Matang mangrove estuary. Out of 162 Enterobacteriaceae isolates collected from Matang mangrove estuaries, E. coli (n=47), Enterobacter spp. (n=42), Klebsiella spp. (n=36), Serratia spp. (n=18) and others (n=19) were identified by biochemical assay. Subsequently, out of the 78 presumptive isolates of Klebsiella spp. and Enterobacter spp., 55 were confirmed as K. pneumoniae by PCR targeting the malate dehydrogenase gene. The confirmed isolates of K. pneumoniae were analyzed for antibiotics susceptibility, capsule production, biofilm formation, exopolysaccharide production and morphotype on Congo red agar plate. Also, the isolates were subjected for virulotyping and genetic fingerprinting with Repetitive Element Palindromic PCR (REP-PCR). Out of the 8 virulence genes, K1, K2 (capsular antigen), wabG, magA (biosynthesis of outer core lipopolysaccharide antigen), rmpA (mucoid phenotype regulator), kfu (iron up-taking system), fimH (fimberia adhesion) and ugE (biosynthesis of capsule and smooth lipopolysaccharide) tested, only fimH, ugE and wabG were detected with high prevalence (95%) among K. pneumoniae isolates. In general, the isolates could be grouped into four major clusters based on the REP-PCR fingerprints, in which isolates with certain similar phenotypes were grouped together. Antibiotics susceptibility test showed that majority of K. pneumoniae isolates (87.3%) were sensitive to the all the antibiotics tested, except for Ampicillin. However, 12.7% of the isolates were found to be multi drug resistant to more than 2 classes of antibiotics. These multi drug resistant isolates were mainly isolated from one station located at river mouth with high salinity (18.03ppt). The waterborne K. pneumoniae from Matang mangrove estuary demonstrated low prevalence (5%) of strong biofilm forming ability. In conclusion, due to presence of some virulence factors like, hypermucoid phenotype, biofilm formation ability, and capsular production and the presence of virulence gene (fimH, wabG, ugE) in these waterborne K. pneumoniae, these localities pose a risk of infection to the villagers.