Prevalence of IMP and VIM Metallo-Beta-Lactamases in Pseudomonas aeruginosa Isolates from Clinical and Environmental Specimens in Intensive Care Units (ICUs) of Rasht Hospitals, Iran

Introduction: Pseudomonas aeruginosa is one of the leading causes of nosocomial infections, and antibiotic resistance of this pathogen is an important concern in treating such infections. The current work was conducted to investigate the prevalence of bla-IMP, and bla-VIM metallo-beta-lactamase (MBL) among clinical and environmental P. aeruginosa isolates obtained from ICUs of different hospitals in Rasht, Iran. Methods: A total number of 35 P. aeruginosa strains including 20 clinical and 15 environmental strains were isolated from ICUs. The isolated bacteria were screened for MBL production using Combined Disc Synergy Testing (CDST) assay. The frequency of bla-IMP and bla-VIM among MBL producing P. aeruginosa (MBL-PA) was investigated using Polymerase Chain Reaction (PCR). Also, the antibiotic susceptibility of all isolates was determined. Results: According to the results, 51% of isolates were regarded as MBL-PA while bla-IMP or bla-VIM genes were detected in 37% of isolates. The environmental isolates showed higher resistance to the majority of antibiotics compared to the clinical isolates, and MBL genes were more prevalent among environmental isolates. Conclusion: Higher resistance of environmental P. aeruginosa strains in ICUs shows a need to pursue newer approaches, including novel cleaning methods and surveillance programs, to reduce nosocomial infections. J Med Microbiol Infec Dis, 2015, 3 (3-4): 62-66.