Clinical characteristics and antimicrobial susceptibility of <i>Eggerthella lenta</i> infection over a 5-year trend at a university hospital in Japan.

<i>Eggerthella lenta</i> (<i>E. lenta</i>) is known to cause intra-abdominal and anaerobic bloodstream infections. However, clinical insights and information on antimicrobial susceptibility in <i>E. lenta</i> infections are limited. This study aimed to elucidate the clinical characteristics and antimicrobial susceptibility of <i>E. lenta</i> infections. Patients with <i>E. lenta</i> isolated from various specimens who presented at Aichi Medical University Hospital between January 2018 and December 2022 were included. Patient information was retrospectively collected from electronic medical records. Logistic regression analysis was conducted to identify risk factors for bloodstream infections. The antimicrobial susceptibility of various antimicrobial agents against isolated strains was investigated. During the study period, seventy cases were classified as infection cases. The median age of patients was 69 years (range: 15-100 years), and 48 (68.6%) were males. The most common site of infection was the lower digestive tract (54.3%). In 70.4% of cases, polymicrobial infections occurred. Community-acquired infection was a significant risk factor for bloodstream infection, with an odds ratio of 4.94 (95% confidence interval: 1.02-23.9). The 30-day mortality rate was 10.0%. Univariate analysis showed lower mortality in patients who underwent surgical intervention than in those who did not (42.9% vs 57.1%, <i>p</i> = 0.02). The proportion of minimal inhibitory concentrations (MICs) of ≥ 32 μg/mL for piperacillin-tazobactam was 6.3%. Additionally, the proportions of MICs of ≥ 8 μg/mL for imipenem and meropenem were 1.4% and 0%, respectively. <i>E. lenta</i> should be considered when blood cultures yield gram-positive rods in community-acquired intra-abdominal infections. Effective treatment involves both antimicrobial agents and surgical interventions.