Prevalence of carbapenemases and ESBL encoding genes among K. pneumoniae isolates obtained from an educational hospital in Ahvaz, Southwestern Iran

Background: K. pneumoniae is a gram-negative pathogen that common cause of nosocomial infections. The rapid spread of multi-drug resistant (MDR) K. pneumoniae is an important issue. This study aimed to identify carbapenemases (Klebsiella pneumoniae carbapenemase [KPC], oxacillinase- 48 [OXA-48], New Delhi metallo-8-lactamase-1 [NDM-1]), oxacillinase-181 [OXA-181] and extended-spectrum beta-lactamases (ESBL) (CTX-M-15) were identified among K. pneumoniae isolates in Ahvaz, Iran. Methods: In this cross-sectional study, conducted from July 2018 to July 2019, isolates of K. pneumoniae obtained from various clinical samples. All Gram-negative bacilli isolates were differentiated on species level by standard biochemical tests. In following, antibiotic susceptibility testing by disk diffusion method, ESBLs, carbapenemase, metallo-beta-lactamase and bla(CTX-M-15), bla(KPC), bla(OXA-48), bla(NDM), and bla(OXA-181) genes were performed. Results: In total, 120 clinical isolates of K. pneumoniae were obtained. The most effective antibiotics for K. pneumoniae isolates were colistin, imipenem, and doripenem, with 98.3%, 64.1%, and 64.1% susceptibility. Thirty-one isolates (25%) were resistant to meropenem disc and considered as carbapenem-resistant. A total of 78 isolates (65%) were ESBLs by double-disc synergy test (DDST) and 25 isolates (20.8%) produced metallo-betalactamase. Among 31 (25%) carbapenem-resistant isolates, 22 isolates (71%) hydrolyzed the meropenem and classified as carbapenemase producers. PCR assays revealed that prevalence of bla(CTX-M-15), bla(KPC), bla(OXA-48), bla(NDM), and bla(OXA-181) genes was 36.7%, 10%, 64.15%, 1.7% and 8.3%, respectively. Conclusion: This study found a high prevalence of MDR K. pneumoniae harboring MBL and ESBL genes. It is recommended that local periodic. Surveys are performed for controlling antimicrobial resistance.