Assessment of Carbapenem Susceptibility and Multidrug-Resistance in Pseudomonas aeruginosa Burn Isolates in Tehran

Background: Pseudomonas aeruginosais an opportunistic pathogen which causes severe, acute and chronic nosocomial infections. These infections are difficult to eradicate since the organisms are usually multidrug-resistant. Carbapenems are considered as the most effective drugs against these isolates. However, recent emergence of carbapenem-resistant P. aeruginosa has become a major healthcare problem. Objectives: The present study was conducted to determine the antibiotic susceptibility of P. aeruginosa burn isolates to 13 antibiotics including imipemen and meropenem. Materials and Methods: One hundred and thirty three P. aeruginosa burn isolates were collected from Shahid Motahari Burn Hospital between July and December 2011. The majority of the isolates were from wounds (88.7%), followed by 5.26% from blood, 4.15% from subclavian catheters and 1.5% from urine. The antibiotic susceptibility profiles were studied by the agar disc diffusion. Results: The results showed 99.2% resistance to carbenicillin, 98.4% to ticarcillin, 96.2% to ciprofloxacin, 95.4% to co-trimoxazole, 94.7% to imipenem and meropenem, 93.9% to piperacillin, 93.2% to azetronam, 92.4% to tobramycin, 91.7% to cefepime, 89.4% to amikacin and ceftazidime, and finally 87.2% to piperacillin-tazobactam. Overall, 100% of the isolates showed multidrug-resistance (resistance to >= 3 classes of antibiotics) including theimipenem-resistant isolates. Conclusions: The high rate of multidrug-resistance is alarming and it is crucial to screen for carbapenem resistance prior to - antibiotic therapy.