metallo-beta-lactamase genes vim-1, spm-1 and imp-1 in pseudomonas aeruginosa isolated from zahedan hospitals

One of the major clinical problems regarding pseudomonas aeruginosa is attributed to the production of metallobetalactamase (mbl) enzymes. this group of enzymes are a member of betalactamases which constitute ambler class b that hydrolyze carbapenems. the current study aimed to evaluate the prevalence rate of metallobetalactamases (mbl), through phenotypic and genotypic methods, and also to investigate antibiotic resistance pattern of pseudomonas aeruginosa isolated from the hospital in zahedan, iran. the minimum inhibitory concentration (mic) of imipenem against pseudomonas aeruginosa was measured for 191 species isolated from zahedan hospitals, after confirmation by biochemical methods and determination of antibiotic resistance pattern (arp). strains with mic > 4 µg/ml were investigated by phenotypic and genotypic methods. in the current study the rate of resistance to imipenem was 5.7% and after carrying out the phenotypic experiments, nine strains were identified as the potential producers of metallobetalactamase (mbl). among them, seven strains were confirmed by polymerase chain reaction (pcr) method. vim1 was the predominant gene in the positive strains. the study results confirmed the presence of metallobetalactamase genes in some of the samples isolated from zahedan hospitals. regarding the importance of metallobetalactamase (mbl) produced by pseudomonas spp. isolated from hospitals, quick identification of clinical samples should be considered as an important and basic step to treat and control infections caused by pseudomonas spp.