Anaerobic bacteria are significant causes of bloodstream, intra-abdominal and other deep-seated infections. Despite their clinical importance, anaerobic antimicrobial susceptibility testing is not routinely performed in clinical laboratories, particularly in Singapore. Over the past few decades, reports of antimicrobial resistance amongst anaerobes like Bacteroides fragilis are steadily increasing. Consequently, anaerobic antimicrobial susceptibility is becoming less predictable and empiric treatment without routine susceptibility testing poses a significant risk of treatment failure. In this study, a retrospective cross-sectional survey was performed in a large tertiary hospital in Singapore to monitor local anaerobic antimicrobial susceptibility patterns and identify emerging resistance trends over a 10-year period. We surveyed the antimicrobial susceptibility of B. fragilis and non-fragilis Bacteroides species using clinical isolates collected in 2014 and 2024. We show that while B. fragilis remains universally susceptible to metronidazole, carbapenem resistance is prevalent in Singapore and clinicians should be cautious when using carbapenem for empiric therapy.
Tan et al. (Sun,) studied this question.