Changing Trend in the Antibiotic Resistance Pattern of Pseudomonas Aeruginosa Isolated from Wound Swabs of Out-Patients and in-Patients of a Tertiary Care Hospital.

CONTEXT Pseudomonas aeruginosa is the most common gram negative bacteria associated with nosocomial infections. Active surveillance of trends in antibiotic resistance of P. aeruginosa is necessary for the selection of appropriate antimicrobial agent for empirical therapy. AIM To assess the rates of antibiotic resistance and multidrug resistance among P. aeruginosa isolates and to observe the trend in its resistance pattern over a period of 5 years. MATERIALS AND METHODS Pseudomonas aeruginosa isolated from wound swabs during January to June 2007 and January to June 2012 were included in the study. Isolates were identified by conventional tests and antibiotic susceptibility was determined by disc diffusion method according to CLSI guidelines. RESULTS A total of 307 Pseudomonas aeruginosa isolates were included in the study. Among these isolates, 165 were isolated during Jan-June 2007 and 142 were isolated during Jan-June 2012. Among in-patients, there was a significant reduction in resistance rates of the isolates to ciprofloxacin (49% to 33%), ceftazidime (50% to 33%), meropenem (35% to 19%) and imipenem (28% to 14%) in 2012. Similarly, the rate of MDR Pseudomonas aeruginosa among the in-patients decreased from 37.9% in 2007 to 23.7% in 2012 (p value 0.0241). There was no significant difference in the resistance rates of the isolates from out-patients during the two study periods. CONCLUSION There was a significant decreasing trend in the resistance rates of the isolates to ciprofloxacin, ceftazidime, meropenem and imipenem. Reduction in the use of ciprofloxacin could be probable reason for the decreased resistance among P. aeruginosa isolates, which needs to be further investigated.