Ruminococcus gnavus bacteraemia in a patient with multiple haematological malignancies

Abstract

We present a case of <i>Ruminococcus gnavus</i> sepsis in a woman suffering from multiple myeloma and myelodysplastic syndrome. <i>R. gnavus</i> , a Gram-positive coccus and a gut commensal, has been described in nine cases of infection in the literature, with most infections having occurred in patients with either gastrointestinal symptoms or prosthesis infections. In this case, <i>R gnavus</i> was identified by mass spectrometry, and showed susceptibility to penicillin, meropenem, tetracycline, metronidazole and clindamycin. The patient was successfully treated initially with intravenous piperacillin/tazobactam and metronidazole, and then switched to oral penicillin and metronidazole. The cause of infection is hypothesized to have been a shift in the gut microbiota towards an excess growth of <i>R. gnavus</i> caused by immunosuppression, and bacterial translocation across a vulnerable mucosal barrier due to prednisolone treatment and severe thrombocytopenia.