Antibiotic utilization trends in Veterans Affairs patients with Stenotrophomonas maltophilia bloodstream infections.

Objective: Stenotrophomonas maltophilia is a multidrug-resistant gram-negative bacillus that can cause serious infections but has limited treatment options. This study aims to establish trends in the treatment of S. maltophilia bloodstream infections (BSI) across the United States in Department of Veterans Affairs (VA) facilities.

Methods: Data was evaluated over a 10-year timeframe (2012 to 2021) in this retrospective cohort study. Veterans with ≥ 1 blood culture with S. maltophilia within a VA medical encounter were included. Microbiology, pharmacy, and patient information were collected through national VA data sources and chart review. Descriptive statistics and Poisson regression were used to summarize patient demographics, facility characteristics, microbiologic data, and treatment trends.

Results: A total of 374 blood cultures positive for S. maltophilia were identified across 75 VA facilities. Of 282 unique patients with BSI, the majority were male (93.6%), white (67.4%), with a mean age of 64 ± 13.1 years. Of those patients, 78% received treatment, 12.8% had a polymicrobial blood culture, and 5.3% had a documented sulfa allergy. Susceptibility results were most reported for trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin, and ceftazidime, with 4.5%, 4.3%, and 44.4% resistant isolates, respectively. Antibiotics most prescribed included TMP-SMX (41.5%) and levofloxacin (39.4%), followed by ciprofloxacin (13.8%) and ceftazidime (12.4%). Combination therapy was prescribed in 33% of patients. No significant trends were found with antibiotic utilization over time.

Conclusions: TMP-SMX and levofloxacin were the most prescribed antibiotics for S. maltophilia BSI treatment. No significant changes were seen with antibiotic prescribing trends in Veterans from 2012 to 2021.