Antibiotic Resistance Patterns and Molecular Characteristics of Metallo-beta-lactamase Producing Non-fermentative Gram-negative Bacilli in Birjand, South-East Iran

Background and Aim : Non-fermentative Gram-negative Bacilli (NFGNB) is known as a major cause of healthcare-associated infections with high levels of antibiotic resistance. The aim of this study was to investigate the antibiotic resistance profiles and the existence of blaIMP, blaVIM, and blaNDM genes among metallo-beta-lactamase (MBL)-producing NFGNB isolates.Methods : In this cross-sectional study, the antibiotic resistance profile of ۱۲۲ clinical NFGNB isolates was determined by the Kirby-Bauer disk diffusion and microdilution broth methods. Bacterial isolates were investigated for the detection of MBLs production using the combination disk diffusion Test (CDDT). The existence of blaIMP, blaVIM, and blaNDM genes in all carbapenem-resistant isolates was determined employing polymerase chain reaction (PCR) assays. Results : High resistance in P. aeruginosa was reported to Cefotaxime and Minocycline, whereas A. baumannii isolates were highly resistant to all antibiotics except Colistin. Multidrug resistance (MDR)-NFGNB (۶۶% vs. ۱۲.۵%, P=۰.۰۰۰۴) and extensively drug resistant (XDR)-NFGNB (۵۵.۷% vs. ۱۲.۵%, P=۰.۰۰۱) isolates were significantly more common in hospitalized patients than in outpatients. The production of MBL was seen in ۴۰% of P. aeruginosa and ۹۳.۳% of A. baumannii isolates. It was found that ۳۳.۳% and ۴۶.۷% of carbapenem-resistant P. aeruginosa isolates, and ۱۳.۳% and ۲۸.۹% of carbapenem-resistant A. baumannii isolates were harboring blaIMP-۱ and blaVIM-۱ genes, respectively. The incidence of MDR (۹۸.۲% vs. ۲۸.۳%, P<۰.۰۰۱) and XDR (۹۶.۴% vs. ۱۱.۷%, P<۰.۰۰۱) in MBL-producing NFGNB isolates was significantly higher than non-MBL-producing isolates. Conclusion : This study demonstrated a higher rate of resistance among NFGNB isolates with an additional burden of MBL production within them, warranting a need for robust microbiological surveillance and accurate detection of MBL producers among the NFGNB.

کلیدواژه ها:

Gram-negative Bacteria ، Carbapenems ، Anti-bacterial agents ، Metallo-beta-lactamase ، Carbapenem resistance.