Beta-lactamase determinants and molecular typing of carbapenem-resistant classic and hypervirulent Klebsiella pneumoniae clinical isolates from southwest of Iran

This study investigated the molecular epidemiology of carbapenem-resistant classic Klebsiella pneumoniae (CR-cKp) and carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKp) isolates in southwestern Iran. From 2019 to 2021, 136 (88.9%) cKp and 17 (11.1%) hvKp isolates were identified using biochemical tests and polymerase chain reaction (PCR). Antibiotic resistance, beta-lactamases, and clonal relatedness of carbapenem-resistant isolates were investigated using disk diffusion, PCR, and enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), respectively. The different markers of hvKp isolates were as follows: string test (35.3%, n = 6/17), magA (11.8%, n = 2/17), rmpA (11.8%, n = 2/17), rmpA2 (52.9%, n = 9/17), iucA (52.9%, n = 9/17), and peg344 (35.3%, n = 6/17). Also, 55.1% (n = 75/136) of cKp and 47.1% (n = 8/17) of hvKp isolates were CR-cKp and CR-hvKp, respectively. All CR-hvKp (100.0%, n = 8) isolates were MDR. Colistin, tetracycline, and tigecycline were the most effective antibiotics. The occurrence of beta-lactamase genes in 75 CR-cKp and 8 CR-hvKp isolates was as follows: bla(NDM) (41.3, 25.0%), bla(IMP) (4.0, 0.0%), bla(VIM) (8.0, 0.0%), bla(GES) (14.7, 25.0%), bla(OXA-48-like) (20.0, 0.0%), blac(CTX-M) (26.7, 12.5%), bla(S)(HV) (24.0, 12.5%), bla(TEM) (10.7, 0.0%), bla(FOX) (6.7, 0.0%), bla(DHA) (6.7, 0.0%), bla(CMY) (5.3, 0.0%), bla(LAT) (12.0, 0.0%), and bla(ACT) (8.0, 0.0%). ERIC-PCR showed a high diversity among isolates. In this study, the occurrence of MDR CR-hvKp isolates harboring bla(NDM) and bla(GES) was detected for the first time in southwestern Iran. To prevent the spread of CR-hvKp and reduce selection pressure, long-term surveillance and more effective treatment strategies should be implemented.