In Vitro Antimicrobial Susceptibility Pattern Among Stenotrophomonas Maltophilia Strains Isolated From Clinical Specimens

Aim: In this study, the determination of in vitro antimicrobial susceptibility rates among Stenotrophomonas maltophilia strains isolated from clinical specimens was aimed. Method: A total of 60 S. maltophilia strains isolated from various clinical specimens sent to Dicle University Hospital clinical microbiology laboratory between January 2006 and September 2011 were included retrospectively in this study. Urine samples were inoculated onto 5% sheep blood agar and Eosin-Methylene Blue (EMB) agar media, quantitatively; other clinical samples were inoculated, qualitatively. Identification of S. maltophilia isolates was performed by conventional methods and fully automated microbiology system. Antimicrobial susceptibility tests were performed by Kirby-Bauer’s disk diffusion method and by broth dilution. Results: A total of 60 S. maltophilia strains isolated from clinical specimens as 24 urine, 15 blood, 11 sputum, four synovial fluids, three cerebrospinal fluids, two wound swabs and one middle ear materials. The resistance rates against antibiotics were detected as 85% (n=51) for piperacillin-tazobactam, 75% (n=45) for levofloxacin, 73% (n=44) for ciprofloxacin, 57% (n=34) for trimethoprim-sulfamethoxazole, 5% (n=3) for meropenem and imipenem, and 0% (n=0) for amikacin. Conclusion: In this study, it was detected that piperacillin-tazobactam can be used as an alternative option other than trimethoprim-sulfamethoxazole, for the treatment of infections due to S. maltophilia at least in our region.