Abstract
Background and aims: Increasing the prevalence of nosocomial infections by multidrug resistant (MDR) Pseudomonas aeruginosa has severely challenged the choice of treatment and led to an increased mortality rate. Thus, this study investigated the frequency of class I and II integrons and its association with MDR.
Materials and Methods: A total of 175 P. aeruginosa isolates were collected from Shahrekord teaching hospitals and Isfahan Shahid Chamran hospital during 12 months (from April 2008 to March 2009). Antibiotic susceptibility was determined by disc diffusion according to the Clinical and Laboratory Standards Institute (CLSI) Antimicrobial Susceptibility Testing. The E-test strips of imipenem, ciprofloxacin, and amikacin were used to identify the minimum inhibitory concentration and MDR bacteria. Finally, the frequency of class I and II integrons genes was evaluated by using the polymerase chain reaction test.
Results: The highest antibiotic resistance and the highest susceptibility belonged to meropenem (86.9%) and polymyxin B (96.0%) by disc diffusion, respectively. By the E-test, the highest and lowest resistance rates were reported for imipenem (97.2%) and ciprofloxacin (86.8%), respectively. The frequency of MDR strains was 82.3% as well. The frequency of class I and II integrons was 57.7% and 17.7% in all P. aeruginosa isolates, as well as 68.1%and 21.5% in the MDR isolates, respectively. There was also a significant correlation between I and II integrons and MDR.
Conclusion: Overall, the resistance to different antibiotics and the frequency of MDR strains among the studied P. aeruginosa isolates were very high. There was also a significant correlation between integrons and multidrug resistance. Regarding the role of integrons in the transfer of drug-resistant genes and the development of MDR strains, the use of appropriate diet and accurate determination of the susceptibility pattern of P. aeruginosa isolates are considered necessary.