Molecular detection of OXA-48 and NDM-1 carbapenemase genes among clinical isolates of Klebsiella pneumoniae recovered from patients attending a private tertiary hospital in Southwestern Nigeria

There have been increasing reports of Klebsiella pneumoniae resistant to β-lactam antibiotics. This study aimed to determine the prevalence of some selected carbapenemase genes among clinical isolates of Klebsiella pneumoniae recovered from patients attending a private tertiary hospital in Southwestern Nigeria. The study was conducted over two months (February-March 2024). A total of 50 clinical isolates of Klebsiella pneumoniae from different clinical specimens were obtained from the Medical Microbiology Department, Babcock University Teaching Hospital (BUTH). The clinical isolates were then characterized using standard microbiological procedures and were tested for susceptibility to meropenem and other classes of antibiotics according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Polymerase Chain Reaction (PCR) detection for OXA-48 and NDM-1 carbapenemase genes was performed on the 50 clinical isolates. PCR analysis showed that 9 (18%) clinical isolates were positive for the OXA-48 gene, 22 (44%) were positive for the NDM-1 gene, 4 (8%) possessed both the OXA-48 and NDM-1 genes, and 23 (46%) possessed neither the OXA-48 nor NDM-1 genes. Antibiotic Susceptibility Testing (AST) revealed that all the clinical isolates were resistant to meropenem. In conclusion, this study demonstrates the presence of OXA-48 and NDM-1 genes in clinical isolates of Klebsiella pneumoniae recovered from patients attending a private tertiary hospital in Southwestern Nigeria, highlighting the role of ESBL (extended-spectrum beta-lactamase) as a major resistance mechanism alongside other mechanisms. Population-based surveillance programs should be implemented to monitor the prevalence and epidemiology of Klebsiella pneumoniae infections at the community level, facilitating early detection of outbreaks and identification of emerging antimicrobial resistance patterns. CORE TIP: This study highlights the significant prevalence of NDM-1 and OXA-48 carbapenemase genes among Klebsiella pneumoniae clinical isolates in a private tertiary hospital in Southwestern Nigeria, with 44% and 18% of isolates harboring these genes, respectively. Notably, 46% of isolates were resistant to carbapenems despite lacking these genes, suggesting alternative resistance mechanisms. The findings underscore the urgent need for enhanced surveillance, infection control measures, and antibiotic stewardship programs to combat the spread of multidrug-resistant Klebsiella pneumoniae in healthcare settings.