Antibiotic resistance and frequency of class 1 integrons among Pseudomonas aeruginosa isolates obtained from wastewaters of a burn center in Northern Iran.

Abstract

Pseudomonas aeruginosa, being responsible of a broad variety of infections, is considered an important nosocomial pathogen. The emergence of multiple-drug resistance among strains of P. aeruginosa appeared as a further public health concern. Due to the considerable ability of multiple-drug resistant P. aeruginosa strains to transmit themselves in the environment, we aimed to investigate the association of class 1 integrons with the antibiotic resistance profile of P. aeruginosa strains isolated from hospital wastewaters. In this cross-sectional study, a total of 100 P. aeruginosa isolates were obtained from raw wastewater samples from February 2010 to January 2011 in a Teaching Burn Hospital in Guilan province. All isolates were identified as P. aeruginosa using standard microbiological tests. Antibiotic susceptibility was investigated using the disk diffusion method according to Clinical and Laboratory Standards Institute recommendations. All isolates were assayed for the presence of the class 1 integrons gene by PCR. Overall, 30 (30%) P. aeruginosa isolates were positive for the presence of class 1 integrons. The highest antibiotic resistance rates in both integron-positive and -negative isolates belonged to cephalexin and cephazolin, with 100% resistance. Amikacin and ciprofloxacin with the lowest level of resistance (13.3%) were the effective antibiotics against integron-positive isolates. The rates of MDR isolates were significantly higher among integron-positive isolates with 43.3% compared to negative isolates with 22.9% (P < 0.05). The results highlight the importance of class 1 integrons in multiple antibiotic resistance among P. aeruginosa isolates. Moreover, the spread of hospital derived wastewaters in the environment can be regarded as the origin of significant reservoirs for antibiotic-resistant pathogens.