High prevalence of multidrug-resistant non-fermentative Gram-negative   bacilli harboring bla   and bla metallo-beta-lactamase genes in Birjand, south-east Iran

Mohammad Hasan Namaei; Masoud Yousefi; Parvin Askari; Babak Roshanravan; Ali Hashemi; Yasaman Rezaei

doi:10.18502/ijm.v13i4.6971

Mohammad Hasan Namaei Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran
Masoud Yousefi Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran
Parvin Askari Department of Microbiology, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran
Babak Roshanravan Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran
Ali Hashemi Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Yasaman Rezaei Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran

DOI: https://doi.org/10.18502/ijm.v13i4.6971

Keywords: Gram-negative bacteria; Carbapenems; Anti-bacterial agents; Metallo-beta-lactamase; Carbapenem resistance

Abstract

Background and Objectives: Non-fermentative Gram-negative Bacilli (NFGNB) is known as a major cause of health- care-associated infections with high levels of antibiotic resistance. The aim of this study was to investigate the antibiotic resistance profiles and molecular characteristics of metallo-beta-lactamase (MBL)-producing NFGNB.

Materials and Methods: In this cross-sectional study, the antibiotic resistance profile of 122 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 bla , bla , and bla NDM genes in all carbapenem-resistant isolates was determined employing polymerase chain reaction (PCR) assays.

Results: High resistance in Pseudomonas aeruginosa was reported to cefotaxime and minocycline, whereas Acinetobacter baumannii isolates were highly resistant to all antibiotics except colistin. Multidrug resistance (MDR)-NFGNB (66% vs. 12.5%, P=0.0004) and extensively drug resistant (XDR)-NFGNB (55.7% vs. 12.5%, P=0.001) isolates were significantly more common in hospitalized patients than in outpatients. The production of MBL was seen in 40% of P. aeruginosa and 93.3% of A. baumannii isolates. It was found that 33.3% and 46.7% of carbapenem-resistant P. aeruginosa isolates, and 13.3% and 28.9% of carbapenem-resistant A. baumannii isolates were harboring bla IMP-1 and bla VIM-1 genes, respectively. The incidence of MDR (98.2% vs. 28.3%, P<0.001) and XDR (96.4% vs. 11.7%, P<0.001) 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.