Characteristics of Colistin-Resistant and Colistin-Sensitive Isolates of Carbapenem-Resistant Klebsiella pneumoniae Among Hospitalized Patients in Tehran, Iran

Background: Resistance to antibiotics is a prominent issue in treating infections caused by Klebsiella pneumoniae. Objectives: The present study aimed to investigate the prevalence of carbapenem and colistin-resistant (ColR) K. pneumoniae and their molecular characteristics in a hospitalized patient in Tehran, Iran. Methods: This cross-sectional study was performed on K. pneumoniae isolated from different wards of a hospital during 2020 - 2021. Following the biochemical identification of the isolates, their antibiotic resistance was evaluated. Genes of blaCTX-M, blaNDM, blaOXA-48, blaKPC, and mcr-1 were identified in isolates by PCR. The data were analyzed using SPSS software. Results: A total of 380 isolates of K. pneumoniae were collected, of which 275 (72.3%) were extended-spectrum beta-lactamase (ESBL) producers, among which 49.4% (n = 136/275) were carbapenemase producers, and 62.5% (n = 85/136) were ColR. blaOXA-48 and blaNDM were the dominant genes. There was a significant correlation between the high prevalence of the blaNDM gene and ColR isolates (P = 0.038). Conclusions: Our findings revealed the high prevalence of carbapenem-resistant isolates, likely due to the excessive clinical use of carbapenems in hospitals. The high prevalence of the blaNDM gene in ColR carbapenem-resistant Klebsiella pneumoniae (CRkP) isolates could indicate the high incidence of a specific clone that contributes to the simultaneous acquisition of resistance genes among patients.