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

Abstract

This study investigated the molecular epidemiology of carbapenem-resistant classic <i>Klebsiella pneumoniae</i> (CR-cKp) and carbapenem-resistant hypervirulent <i>Klebsiella pneumoniae</i> (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%, <i>n</i> = 6/17), <i>magA</i> (11.8%, <i>n</i> = 2/17), <i>rmpA</i> (11.8%, <i>n</i> = 2/17), <i>rmpA2</i> (52.9%, <i>n</i> = 9/17), <i>iucA</i> (52.9%, <i>n</i> = 9/17), and <i>peg344</i> (35.3%, <i>n</i> = 6/17). Also, 55.1% (<i>n</i> = 75/136) of cKp and 47.1% (<i>n</i> = 8/17) of hvKp isolates were CR-cKp and CR-hvKp, respectively. All CR-hvKp (100.0%, <i>n</i> = 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: <i>bla</i> _NDM (41.3, 25.0%), <i>bla</i> _IMP (4.0, 0.0%), <i>bla</i> _VIM (8.0, 0.0%), <i>bla</i> _GES (14.7, 25.0%), <i>bla</i> _OXA-48-like (20.0, 0.0%), <i>bla</i> _CTX-M (26.7, 12.5%), <i>bla</i> _SHV (24.0, 12.5%), <i>bla</i> _TEM (10.7, 0.0%), <i>bla</i> _FOX (6.7, 0.0%), <i>bla</i> _DHA (6.7, 0.0%), <i>bla</i> _CMY (5.3, 0.0%), <i>bla</i> _LAT (12.0, 0.0%), and <i>bla</i> _ACT (8.0, 0.0%). ERIC-PCR showed a high diversity among isolates. In this study, the occurrence of MDR CR-hvKp isolates harboring <i>bla</i> _NDM and <i>bla</i> _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.