Desulfovibrio Bacteremia in Older Patients with Abdominal Infections, Japan, 2020–2025

We retrospectively identified eight episodes of Desulfovibrio bacteremia at a single tertiary-care hospital in Japan between 2020 and 2025. All patients were ≥65 years of age, and most had comorbidities. The primary source of the infection was the abdomen. The isolates included two D. desulfuricans , D. fairfieldensis , D. falkowii , and D. legallii . Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified only D. desulfuricans and D. fairfieldensis , whereas sequence-based identification was required for other species. The minimum inhibitory concentrations (MICs) were low for ampicillin/sulbactam and metronidazole and higher for penicillin, piperacillin/tazobactam, and cefoxitin. Isolates with elevated cephalosporin MICs harbored β-lactamase genes, including blaDES-1-like, blaCfiA-like, and blaMUN-1. Curved or spiral gram-negative rods in anaerobic blood culture bottles, together with a positive desulfoviridin assay, should incite suspicion of Desulfovibrio bacteremia of gastrointestinal origin. Sequence-based identification improves the recognition of less common species.