Epidemiology and Clinical Profiles of Bacteroides fragilis Bacteremia in a Tertiary Care Setting: A 5-Year Review.

BACKGROUND

Anaerobic infections remain clinically significant yet underrecognized due to diagnostic challenges and limited routine susceptibility testing in clinical laboratories. Among these pathogens, Bacteroides fragilis is a clinically important anaerobe associated with bloodstream and deep-seated infections. This study aimed to evaluate the epidemiology, clinical characteristics, and antimicrobial resistance patterns of Bacteroides fragilis bacteremia in a tertiary care hospital.

MATERIALS AND

METHODS

This retrospective study included patients with blood cultures positive for Bacteroides fragilis between July 2018 and January 2023. Demographic characteristics, clinical features, infection sources, treatment regimens, and antimicrobial resistance patterns were analyzed.

RESULTS

Our analysis found a higher rate of Bacteroides fragilis bacteremia among cancer patients, likely linked to cancer treatments that compromise gastrointestinal defenses. Notably, both hospital-acquired infection (OR: 4.99, 95% CI: 1.3-19.07, p = 0.019) and respiratory tract infection (OR: 8.19, 95% CI: 1.21-55.35, p = 0.031) were associated with an increased risk of death within 30 days, highlighting the importance of vigilance in healthcare environments. Resistance to clindamycin was substantial, while ampicillin resistance was expected because of the intrinsic resistance profile of Bacteroides species. While carbapenem resistance was uncommon, its presence signals a shifting resistance pattern. Metronidazole remained effective, supporting its continued use.

CONCLUSION

Bacteroides fragilis bacteremia is associated with significant mortality, particularly in nosocomial settings. Continuous surveillance and appropriate antimicrobial stewardship are essential for effective management.