Molecular Characterization and Resistance Gene Co-occurrence in Carbapenem-Resistant Klebsiella peumoniae from a Bangkok Tertiary Hospital, Thailand.

INTRODUCTION: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a significant global health concern due to its high morbidity and mortality rates and limited treatment options. We investigated the molecular characteristics and co-occurrence of resistance genes in CRKP isolates from a tertiary hospital in Bangkok, Thailand. METHODOLOGY: Seventy-three non-repetitive CRKP isolates were collected from clinical specimens of hospitalized patients from August 2022 to January 2023. Identification was confirmed using standard microbiological tests and MALDI-TOF-MS. Antimicrobial susceptibility was assessed using the MicroScan system. PCR was employed to detect carbapenemase genes and extended-spectrum beta-lactamases (ESBLs). RESULTS: The study revealed a high resistance rate among the CRKP isolates to cephalosporins, aminoglycosides, fluoroquinolone, and trimethoprim/sulfamethoxazole. Of the 73 CRKP isolates, 98.6% were susceptible to tigecycline, and 46.6% remained susceptible to ceftazidime-avibactam. Molecular analysis revealed that blaOXA-48-like (93.2%) and blaNDM-1 (43.8%) were the predominant carbapenemase genes. All isolates harbored the ESBL gene blaCTX-M-15. The co-occurrence of blaOXA-48-like and blaNDM-1 was observed in 39.7% of the isolates. Ward-specific analysis revealed the highest diversity and frequency of co-resistance gene profiles in isolates from the medical ward, while isolates from ICUs also exhibited complex gene combinations involving multiple ESBL and carbapenemase genes. CONCLUSIONS: This study reveals a high prevalence of blaOXA-48-like and blaNDM-1 genes among CRKP isolates in a tertiary hospital in Bangkok. The diversity of resistance profiles and the clustering of complex gene combinations, particularly in medical and ICU wards, underscore the need for continuous molecular surveillance and stringent infection control measures to manage the spread of CRKP in healthcare setting.