high prevalence of multidrug-resistant non-fermentative gram-negative bacilli harboring bla imp-1 and bla vim-1 metallo-beta-lactamase genes in birjand, south-east iran

Background and objectives: non-fermentative gramnegative 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 metallobetalactamase (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 imp, bla vim, 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 carbapenemresistant a. baumannii isolates were harboring bla imp1 and bla vim1 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 mblproducing nfgnb isolates was significantly higher than nonmblproducing 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.