Diversity of carbapenemase genes among carbapenem resistant Klebsiella pneumoniae in a tertiary care hospital in Bangkok, Thailand.

Multidrug resistant (MDR) gram-negative bacilli associated with hospital-acquired infections are commonly resistant to carbapenems. Klebsiella pneumoniae is a common MDR Enterobacterales in Thailand. In this study, we investigated the distribution of five carbapenemase genes (blaNDM, blaOXA-48, blaIMP, blaVIM, and blaKPC) among 62 carbapenem resistant K. pneumoniae (CRKP) collected in 2022 from patients admitted to a tertiary care hospital in Bangkok. The frequencies of isolates carrying a single carbapenamase gene were 39% for blaOXA-48 and 19% for blaNDM. Interestingly the frequency of the carriers of both genes was as high as 29% and none of the isolates carried blaKPC, commonly reported elsewhere. The studied genes were not identified in 7 isolates (11%). CRKP carrying blaNDM was more frequently identified in medical wards, associated with higher mortality rate and 100% resistant to ceftazidime/avibactam while the one carrying only blaOXA-48 was 92% susceptible to ceftazidime/avibactam. This study confirms the advantage of molecular methods for differentiating between mechanisms of carbapenem resistance in K. pneumoniae.