Clinical and microbiological characteristics of Eggerthella lenta bacteremia at a Japanese tertiary hospital.

Eggerthella lenta is an important cause of anaerobic bloodstream infections and is associated with high mortality. However, there are few reports of E. lenta infection in Japan. This study aimed to evaluate the clinical and microbiological characteristics of bacteremia caused by E. lenta in Hiroshima, Japan. We retrospectively analyzed E. lenta bacteremia patients at the Hiroshima University Hospital between January 2012 and December 2020. During the study period, 14 patients with E. lenta bacteremia were identified. All E. lenta isolates were cultured in anaerobic bottles, and the median time to blood culture positivity was 52.9 h. In most cases (85.6%), the source of E. lenta bacteremia was associated with intra-abdominal infections, and colon perforation was the most frequent source of E. lenta bacteremia (42.9%, n = 6). Antimicrobial susceptibility testing showed high minimal inhibitory concentrations (MIC) of piperacillin-tazobactam (TZP) and 100% susceptibility to ampicillin-sulbactam, carbapenems, and metronidazole. This study demonstrates that E. lenta bacteremia is associated with intra-abdominal infections, particularly colon perforation, and a high MIC of TZP. When gram-positive anaerobes are detected in the blood cultures of patients with severe intra-abdominal infections, clinicians should suspect E. lenta, and it may be better to change antimicrobial agents from TZP.