Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 18 1 2026 02 14 23 31 Thowiba Jameel Department of Biology, Graduate School of Natural and Applied Science, Erciyes University, Kayseri, Türkiye; Department of Biology, Faculty of Science, Tikrit University, Tikrit, Iraq Abdurrahman Ayvaz Department of Biology, Faculty of Science, Erciyes University, Kayseri, Türkiye Pınar Sağıroğlu Department of Medical Microbiology, School of Medicine, Erciyes University, Kayseri, Türkiye Mustafa Atalay Department of Medical Microbiology, School of Medicine, Erciyes University, Kayseri, Türkiye 2025 05 02 2025 09 26 Background and Objectives: Carbapenem Resistance Klebsiella pneumonia (CRKP ), mostly caused by carbapenemase enzymes, poses a serious public health threat due to limited treatment options. This study aimed to genotypically identify carbapenemase-encoding genes in CRKP isolates recovered from fecal swabs and to correlate these genotypes with phenotypic antibiotic resistance profiles. Materials and Methods: In this study, fecal samples from 150 hospitalized patients were screened for K. pneumoniae. Phenotypic testing included the Phoenix automated system, CHROMagar KPC, biochemical tests, and disk diffusion assays. Genotypic analysis was performed using the BD MAX Checkpoint CPO PCR test, marking its first use in Kayseri, Türkiye, to detect carbapenemase genes in this pathogen. Results: Out of 150 fecal samples, 47 tested positive for K. pneumoniae, with 28 (59.6%) identified as carbapenem-resistant (CRKP). Molecular analysis identified five distinct carbapenemase gene patterns among these resistant isolates. The most prevalent gene, blaOXA-48, was found alone in 60.7% of CRKP isolates, followed by blaNDM in 3.6%; blaKPC was not detected. Co-occurrence of genes was observed as follows: blaOXA-48/blaNDM (14.3%), blaOXA-48 with blaVIM/blaIMP (10.7%), and blaOXA-48 with blaNDM and blaVIM/blaIMP (10.7%) in CRKP clinical isolates. Conclusion: The study found that blaKPC was consistently absent, while blaOXA-48 was highly prevalent and exhibited co-occurrences of carbapenemase genes. It underscored the need for strict hospital surveillance and effective infection control to prevent the spread of CRKP strains. Rapid molecular methods, such as the BD MAX multiplex PCR, have shown promise in accurately and efficiently identifying carbapenemase genes. https://ijm.tums.ac.ir/index.php/ijm/article/view/5476 https://ijm.tums.ac.ir/index.php/ijm/article/download/5476/1858