Abstract
BACKGROUND: Emergence of bla (KPC) and bla (NDM) co-producing Klebsiella pneumoniae strains have led to the limited therapeutic options for clinical treatment. Understanding the diversity and frequency of resistance and virulence genes of these isolates is of great significance. PURPOSE: The aim of this study is to research the diversity and frequency of resistance and virulence genes in the bla (KPC) and bla (NDM) co-producing Klebsiella pneumoniae strains. METHODS AND RESULTS: In this study, 117 K. pneumonia strains were isolated from China, and among of which, 24 were found to be bla (KPC) and bla (NDM) co-producing with significant resistance against almost all the commonly used antibiotics. Additionally, 4 strains were hypermucoviscous and 8 showed high serum resistance. Overall, bla (SHV), bla (CTX-M), tetA and sul1 resistance genes found in 100% of the isolates, followed by bla (TEM) (95.8%), oqxA/B (91.7%), qnrB (87.5%), aac(6')Ib-cr (83.3%), bla (DHA) (79.2%), rmtB (66.7%), qnrS (54.2%), cat(54.2%), floR (50.0%), sul2 (45.8%) cmlA (20.8%)andbla (CMY) (8.33%), respectively. What' more, seven bla (CTX-M) subtypes [bla (CTX-M-14) (n=18), bla (CTX-M-3)(n=11), bla (CTX-M-65) (n=4), bla (CTX-M-15) (n=3), bla (CTX-M-28) (n=2), bla (CTX-M-55) (n=2), bla (CTX-M-22) (n=1)] and six bla (SHV) subtypes [bla (SHV-12)(n=16), bla (SHV-11) (n=4), bla (SHV-2a)(n=1), bla (SHV-1)(n=1), bla (SHV-38)(n=1) and bla (SHV-28)(n=1)] were detected. The frequency of virulence genes was as follows: 100% for entB, ybtS and irp, 95.8% for mrkD, 91.66% for fimH, 79.2% for iutA, 62.5% for iroBCDE, aerobactin and kfu, 66.7% for allS, 45.8% for wcaG, 37.5% for rmpA, 20.8% for pagO and 16.7% for magA. CONCLUSION: From this study, we concluded that the bla (KPC) and bla (NDM) co-producing Klebsiella pneumoniae strains have a high diversity and frequency of resistance and virulence genes. This study may offer hospitals important information about the control of infections caused by bla (KPC) and bla (NDM) co-producing Klebsiella pneumoniae.