Antibiotic Resistance Profile Among Stenotrophomonas maltophilia Clinical and Environmental Isolates

Background: This study was conducted to compare the resistance profile of Stenotrophomonas maltophilia isolates -collected from clinical and environmental sources in a hospital- for different antibiotics to clarify their clonal relatedness. Methods: In this study, a total of 22 S. maltophilia isolates collected from 400 different clinical and environmental samples from Imam Reza Hospital were subjected to the analysis. Antibiotic susceptibility testing for each isolate was carried out by the disc diffusion method and according to the CLSI guidelines. Results: Among 22 S. maltophilia isolates, ten isolates were obtained from clinical specimens, and 12 were obtained from the environment. The isolates showed the lowest and highest antibiotic resistance to chloramphenicol and trimethoprim-sulfamethoxazole and chloramphenicol (18.2%) and meropenem (100%), respectively, and resistance to the other antibiotics were as follows: Gentamicin 22.7%, tobramycin 50.0%, aztreonam 63.6%, amikacin 63.6%, ceftriaxone 68.2%, and ceftazidime 68.2%. The antibiotic profile of S. maltophilia strains differed from tobramycin, aztreonam, amikacin, ceftriaxone, trimethoprim-sulfamethoxazole, ceftazidime, chloramphenicol, and gentamicin between clinical and environmental samples. Conclusions: Based on the high antibiotic resistance of S. maltophilia isolates and various responses to the selected antibiotic, chloramphenicol is the best therapeutic option, with 81.8% susceptibility. The early diagnosis and determination of antibiotic resistance patterns have the utmost importance.