Fusobacterium nucleatum infections: clinical spectrum and bacteriological features of 78 cases

Few series describe the clinical spectrum of Fusobacterium spp. infections. Among them, fewer discuss F. nucleatum, even though there are many clinical cases. We performed a retrospective study over 8 years (from 2007 to 2014) in Limoges University Hospital, France, to assess clinical and bacteriological aspects of infections due to F. nucleatum. Eighty-one patients with F. nucleatum positive cultures were included in this study, irrespective of sample origin. Abscesses (n = 43), bacteraemia (n = 18) and bone infections (n = 8) were the most common types of infections, Abscesses were found in various organs (mostly skin, brain, pleura, liver). Co-morbidities were found in 38 patients (47 %) with neoplasia, diabetes, and alcoholism and history of smoking. There were more neoplasms in patients with bacteraemia than in patients with abscesses (p = 0.007). In 51 cases (65.4 %), infection was polymicrobial, either during bacteraemia or abscesses. Main associations were with Streptococcus spp., Peptostreptococcus spp. and/or Prevotella spp. The sources of infection, when found, were either dental or gastrointestinal. All isolates were susceptible to penicillin, clindamycin and metronidazole. Infections involving F. nucleatum are uncommon and potentially severe, with many abscesses requiring surgery. Bacteraemia was mainly associated with co-morbidities such as cancer. Polymicrobial infections were very common and there is probably interaction and/or synergy between F. nucleatum and some other commensal bacteria to cause infections and abscesses.