Frequency of Occurrence of Stenotrophomonas maltophila in Dena and Ghotbedine Hospitals in Shiraz and the Evaluation of their Antimicrobial Susceptibility

Background and Objectives:Stenotrophomonas maltophilia is a gram negative bacterium, and an emerging pathogen. Recently, this bacterium has been isolated from different sourcehospitals. Several reports indicate that most of this Stenotrophomonas maltophilia strains are resistant to many antibiotics and they can be considered as multi-drug resistance. This study was conducted to determine frequency of occurrence of this bacterium in hospitals (Dena and Ghotbedine) in Shiraz . Then, antibiotic susceptibility of the isolates was assessed. Methods and Methods: The present study was carried out during six mounths from spring to summer in 1397.In total, 360 clinical samples (Respirator, Digestive,wound ) were collected from patients with different infections. Then, the samples transferred to laboratory and subjected to microbiological analysis. The isolates were identified by phenotypic and genotypic methods (using special primer). In addition, antimicrobial susceptibility of the isolates to antibiotics (trimethoprim- sulfomethoxazole, minocycline, levofloxacin, tetracyclin and ciprofloxacin) was determined by disk diffusion method. Then, susceptibility of all isolates was evaluated using CLSI protocol and the results were recorded. (Staphylococcus aureus ATCC 25923 was used as standard of antisusceptibility test). Results: The results obtained indicated that out of 360 clinical samples, 119 Stenotrophomonas maltophilia were detected. All of these isolates were susceptible to minocycline and levofloxacin. In addition, 68,32and 20 strains were susceptible, resistant and intermediate to tetracycline respectively.118 strains were susceptible and one strain was resistant to ciprofloxacin. 79, 18 and 22 strains were susceptible, resistant and intermediate to trimethoprim- sulfamethoxazole, respectively. Conclusion: Our findings showed that frequency of occurrence of Stenotrophomonas maltophilia in hospitals (Dena and Ghotbedine) in shiraz was high. On the other hand, the Stenotrophomonas maltophilia isolated in the present study were totally susceptible to minocycline and levofloxacin. Therefore, these antibiotics are recommended for the treatment of infections Stenotrophomonas maltophilia.