Context: Pseudomonas aeruginosa is an important pathogen which causes nosocomial infections in immunocompromised patients, especially in hospitalized burn patients. In recent times, it has emerged as a widespread Multi Drug Resistant (MDR) pathogen which requires antibiotic susceptibility testing on a regular as well as a periodic basis.
Aim of the study: The present study was undertaken to determine the antibiogram of P. aeruginosa which was isolated from inpatients and environmental sources, and to type the strains, based on their antibiogram patterns.
Settings and design: A prospective study was undertaken with 525 samples (blood and wound swabs) which were taken from 60 patients who were admitted to Vardhman Mahavir Medical College and Safdarjang hospital with burn injuries and with 101 samples which were obtained from environmental sources viz. surgical instruments, dressings, suction devices, sinks, antiseptic solutions, etc.
Materials and methods: The strains were cultured and identified by standard microbiological techniques and Kirby- Bauer disc diffusion antibiotic susceptibility testing was done for each.
Statistical analysis: Chi -squire tests were done and p- values of less than 0.05 were considered to be significant.
Results: Fifty six strains and two strains, respectively, of P. aeruginosa were isolated from inpatients and environmental samples (one strain from sink and one strain from door wall, among the two) respectively. In total, 58 (81%) P. aeruginosa strains were found to be resistant to aminoglycosides, 41-70% were resistant to beta-lactams - piperacillin, ceftazidime, and aztreonam, 34.5% were resistant to piperacillin-tazobactam, 12.06% were resistant to ciprofloxacin and 13-19% were resistant to carbapenems. All strains were sensitive to colistin. P. aeruginosa was resistant to three of the four 'in-use' drugs i.e. piperacillin+tazobactam, imipenem, ceftazidime, and gentamicin, which was taken as MDR, which depicted MDR percentage as 36.2 (21/58).
Conclusion: Strategies of optimal prescribing, including control of antibiotic usage, coupled with periodic studies on MDR P. aeruginosa infections in burn patients, appear to be leading priorities which help in improving therapeutic gains in such patients.
Keywords: Antibiotyping; Multidrug resistance; Pseudomonas aeruginosa.