Temporal shifts in the predominant carbapenemase gene types among carbapenemase- producing Klebsiella pneumoniae isolated in Bangkok, Thailand, during 2013-2016

Introduction. Carbapenemase-producing Enterobacteriaceae (CPE) have emerged as a global threat to public health , clini-cal practice. Hypothesis/Gap Statement. In Thailand, reports describing CPEs carrying blaNDM and blaOXA-48- like genes have been increasing recently; however, data on detailed plasmid analysis and temporal shift of sequence type and carbapenemase type are limited. Aim. In this study, we analysed whole-genome sequencing (WGS) data of clinically isolated carbapenemase-producing Kleb-siella pneumoniae (CPKP) to reveal the molecular epidemiology of CPKP in a tertiary -care hospital in Bangkok, Thailand. Methodology. Seventy -seven non-duplicated CPKP isolates collected during 2013-2016 were examined for their drug -resistance genes, sequence types and phylogenetic relationships. Results. All the tested isolates possessed carbapenemase gene(s) , the major type of carbapenemase gene in 2014-2015 was blaNDM-1, whereas isolates in 2016 harboured more blaOXA-232 than blaNDM-1. Other carbapenemase gene variants, such as blaNDM-4, blaNDM-5, blaOXA-48, blaOXA-181 and blaIMP-14 were detected in some CPKP isolates. Furthermore, this study revealed that CPKP co-harbouring two genes, blaNDM-1 and blaOXA-232 or blaOXA-181, emerged during this period. Notably, such isolates co-carrying the two carbapenemase genes emerged in three different sequence types, even in a single hospital, and then spread clonally. The WGS of CPKP revealed a temporal shift of the predominant carbapenemase genes from blaNDM-1 to blaOXA-232 along with a varia-tion in other carbapenemase gene types within a span of 4 years. Conclusion. Our findings suggest that a substantial change in CPE types occurred in Thailand and potentially in Southeast Asian countries.