Molecular Epidemiology of Pseudomonas aeruginosa Isolated from Burn Patients

Abstract

Background & aim: Because of emerging multi-drug resistance (MDR) Pseudomonas aeruginosa strains, treatment of burn patients infected by this bacterium is difficult. The aim of this study was to detect antimicrobial profile and molecular epidemiology of metallo-beta-lactamase (MBL) producer strains. Methods: In this cross-sectional investigation 270 Pseudomonas aeruginosa isolates were collected from the burn patients. Carbapenem sresistance strains were detected by phenotypic E-test method. Susceptibility profiles of metallo-β-lactamase (MβL) enzyme producing isolates of this bacterium to 11 antimicrobial drug were determined by disc diffusion method according Clinical and Laboratory Standards Institute (CLSI) guidelines. The genetic correlations between isolates were determined by Pulsed-Field Gel Electrophoresis (PFGE) method. Results: Among 270 P. aeruginosa isolates, 60 (22.2%) strains showed resistant to meropenem (MEM) and imipenem (IMI) and were considered as metallo-β-lactamase positive. All metallo-β-lactamase positive isolates were resistant to five tested antimcrobial while their sensitivities to the three best effective antibiotics including ciprofloxacin, amikacin and ceftazidime were 1.7%, 6.7 % and 23.3%, respectively. Majority of the isolates (71.6%) showed more than 80% similarity based on the drawn dendrogram. Conclusion: Our results showed, the tested antimicrobials are not safe to prescribe for burn patients. According PFGE pulsotypes, a limited number of P.aeruginosa types are common in the hospital burn unit which infect the patients hospitalized in this ward