Stenotrophomonas maltophilia: An emerging pathogen in sepsis

Abstract

Background: Stenotrophomonas maltophilia, once regarded as an organism of low virulence, has evolved as a significant opportunistic pathogen causing severe human infections in both hospital and community settings, especially among highly debilitated patients. Objectives: (1) Identification of S. maltophilia in sepsis and (2) assessment of sensitivity pattern/minimum inhibitory concentration (MIC) of S. maltophilia and its multidrug resistance by VITEK 2 Compact system and by Kirby–Bauer (KB) disk diffusion method. Materials and Methods: This is a retrospective laboratory-based study analysis conducted in a tertiary care center, i.e., Bangalore Medical College and Research Institute, from July 2018 to June 2019. Samples from clinically suspected sepsis patients were processed by standard microbiological methods. VITEK 2 compact (Biomerieux) was used for final identification and MIC. Antibiotic susceptibility was tested by KB disk diffusion method for cotrimoxazole (1.25/23.75 μg) and levofloxacin (5 μg) following the Clinical and Laboratory Standards Institute guidelines M100. Results: Among 18,949 samples collected from suspected sepsis patients, during a 1-year period, 50 isolates were identified as S. maltophilia. Nineteen were isolated from blood; 6 from pus and ascitic fluid; 4 from cerebrospinal fluid, endotracheal aspirate, and pleural fluid; 1 from urine and cornea; and 4 from other sites. The organisms showed multidrug resistances and were sensitive to trimethoprim-sulfamethoxazole and levofloxacin. Conclusion: S. maltophilia was found to be the third most common nonfermenters after Acinetobacter spp. and Pseudomonas aeruginosa with multidrug resistance. As its isolation is increasing, it is important to study the epidemiology, antimicrobial susceptibility profile, and clinical outcomes of these isolates.