Isolation, Antibiotic Resistance Determination, and Genotypic Analysis of Pseudomonas Aeruginosa Strains Causing Urinary Tract Infection in Catheterized Patients of Shohada and Labafi Nejad Hospitals

Urinary tract infection is the most common nosocomial infection worldwide. Microorganisms causing urinary tract infections are resistant to most of the antibiotics. Pseudomonas aeruginosa (P. aeruginosa) is one of the major causes of nosocomial infections and its antibiotic resistance leads to medical implications associated with urinary tract infections. The aim of this study was to assess the prevalence of P. aeruginosa strains to identify their in-vitro susceptibility to antimicrobial agents and to determine genetic diversity of them.

Urine samples were obtained from catheterized patients in Shohada and Labafi Nejad hospitals, Tehran, Iran, and cultured by standard loop method. The cultures with more than 105 CFU/ml were assumed as positive. After identification of bacterial species by biochemical tests, susceptibility of each isolate was assessed by disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In order to analyze bacterial genotypic diversity, pulsed-field gel electrophoresis (PFGE) was performed.

116 out of 163 urine samples were positive for bacterial isolates. Pseudomonas species were placed in third step of the most frequent isolates. Antibiotic sensitivity was observed against most of antimicrobial agents. Some of strains were genetically similar.

This study revealed that isolated strains were sensitive to wide range of antibiotic agents. In addition, common type strains were responsible of causing inter- and intra-hospital urinary tract infections in catheterized patients.