Molecular Analysis of Imipenem Resistant Mechanisms in Klebsiella Pneumonia Isolates

• Main Authors: Li, Chia-Chi, 李家其
• Other Authors: Liao, Chao-Tsai
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/92572378462824283068

碩士 === 中臺科技大學 === 生物科技研究所 === 103 === Seven isolates of carbapenem-resistant Klebsiella pneumoniae (named KpC1-KpC7, respectively) were isolated from clinical specimens obtained from patients admitted to Feng yuan Hospital Ministry of Health and Welfare from March 2011 to September 2012. The goal of this study is to analyze correlation between carbapenem-resistant and beta-lactamase gene of these strains. The minimal inhibitory concentration (MIC) of antimicrobial agents was performed by Vitek2. The MIC results showed that the 7 K. pneumoniae isolates were resistant to imipenem. The modified Hodge test (MHT) was performed and interpreted according to the 2011 recommendations of the Clinical and Laboratory Standards Institutes. All 7 imipenem-resistant K. pneumoniae isolates showed positive results. Detection of genes encoding beta-lactamases was analyzed by polymerase chain reaction and DNA sequencing. The results revealed that KpC1 strain carry CMY-2 gene, KpC2 strain carry IMP-8, CMY-2, CTX-M-17 and SHV-12 genes, KpC3, KpC4 and KpC5 strains carry KPC-2, IMP-8, CMY-2 and SHV-12 genes, KpC6 strain carry IMP-8, DHA-1, CTX-M-17 and SHV-5 genes, KpC7 strain carry KPC-2, IMP-8, CMY-2, DHA-1 and SHV-11 genes. Multilocus sequence typing (MLST) experiments showed that all isolates shared the same sequence type (ST), ST11, except for one isolate (KpC6) of ST147. The plasmid conjugation results indicated that the KPC-2, IMP-8, CMY-2 and SHV-11 genes are located on conjugative plasmid can be transferred to E.coli 20R764 from KpC7 strain. In addition, the EKpC7 transcojugant also presents multiple antibiotics resistance increased. In conclusion, two carbapenemase genes, KPC-2 and IMP-8, were identified in 7 imipenem-resistant K. pneumoniae isolates. Other carbapenemase genes such as GES, SPM, AIM, VIM,OXA-48, GIM, BIC, SIM, NDM and DIM were not detected. Furthermore, the genetic combinations SHV-12 and CMY-2 were prevalent in 7 imipenem-resistant K. pneumoniae isolates.