prevalence and characteristics of metallo-beta-lactamase-positive and high-risk clone st235 pseudomonas aeruginosa at ardabil hospitals

Background: carbapenems are the most commonly administered drugs for the treatment of multidrug-resistant pseudomonas aeruginosa (mdr p. aeruginosa) infections. however, carbapenem-resistant p. aeruginosa is spreading rapidly and has led to a new threat to human health worldwide. objectives: the current study aimed to determine the prevalence of imipenem-resistant p. aeruginosa, detect metallo- -lactamase (mbl)-producer isolates, and evaluate their clonal relationships in strains isolated from patients referring to the hospitals of ardabil city, iran. methods: the resistance rate to imipenem was evaluated using the disk diffusion method. double-disk synergy test and pcr technique were used for phenotypic and genotypic screening of mbl-positive p. aeruginosa, respectively. ultimately, enterobacterial repetitive intergenic consensus-polymerase chain reaction (eric-pcr) and multilocus sequence typing (mlst) methods were used for assessing clonal relatedness among the isolates. results: the prevalence of imipenem-resistant p. aeruginosa strains was estimated at 57.1% (48 out of 84 isolates). in addition, 45 (93.7%) out of 48 imipenem-resistant p. aeruginosa isolates were phenotypically screened as mbl-positive, among which 16 (35.5%) and three (6.6%) isolates harbored blaimp and blavim^-1 genes, respectively. however, blandm, blasim-2, blaspm, and blagim-1 genes were not detected in this study. mbl-producing p. aeruginosa strains were divided into 42 eric-pcr types. based on the results of mlst, p. aeruginosa st235 was the only identified sequence type. conclusions: our results revealed a high and alarming prevalence of imipenem-resistant and blaimp-positive p. aeruginosa st235 at ardabil hospitals. continuous monitoring is essential to control the further spread of this highly virulent and drug-resistant clone.