Diversity and frequency of resistance and virulence genes in bla _KPC and bla _NDM co-producing Klebsiella pneumoniae strains from China

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.