Frequency of blaIMP, blaNDM, blaKPC, and blaVIM carbapenemase-encoding genes among gram-negative bacteria isolates from hospitalized patients in Baghdad City, Iraq

Abstract

Carbapenemase-encoding genes have been spreading among gram-negative bacteria, which is considered the most important threats to human health. Metallo p-lactamases including IMP, VIM, and NDM are the most predominant types, which confer resistance to Carbapenem group. This study aimed to investigate the frequency of blaNDM, blaKPC, blaVIM, and blaIMP genes across gram-negative bacteria isolated from different clinical specimens in Medical City Hospital in Baghdad, Iraq. Fifty-two isolates were identified phenotypically using conventional biochemical tests. Vitek 2 identification system was used for confirmation of the identification. The antimicrobial sensitivity for the isolates was performed using Kirby-Bauer disk diffusion method. The carbapenemase-encoding genes (blaIMP, blaVIM, blaNDM, and blaKPC) were screened by polymerase chain reaction (PCR)- based technique. The results showed that, from a total of 52 isolates isolated from hospital in Baghdad city, 13 (25) were Acinetobacter baumannii and 39 (75) were Enterobacteriaceae (10 of Serratia spp, 17 of E. coli, and 12 of Enterobacter cloacae). According to antibiotic susceptibility results, 96 of isolates were resistance to ceftriaxone, 92.3 to ciprofloxacin, and 90.4 to cefotaxime by phenotypic testing. Within the isolates, blaVIM gene was the most prevalent gene, which was detected in 48.1 of the isolates, followed by blaIMP gene in 19.2, blaNDM gene in 9.6, and blaKPC gene in 5.7. This study reveals that the dissemination rate of carbapenemase-encoding genes was not as reported to be high among isolates. The results showed higher frequency to the blaVIM gene than other encoding genes for carbapenemase-encoding genes. These results suggest a periodic screening and follow-up program to detect antibiotic resistant genes, and also the need to develop appropriate management for antimicrobial resistance. © 2021. All Rights Reserved