ObjectiveAlthough uncommon, Fusobacterium infections have a wide clinical spectrum, ranging from local pharyngeal infections to septic shock. Our aim was to characterize and analyze the clinical features and outcomes in patients with Fusobacterium infections, and determine which variables were able to predict a poor outcome.MethodsWe conducted a retrospective, hospital-based study using the computerized records of a second-level Spanish general hospital, serving a population of 155,000 inhabitants. The cohort was enrolled among patients cared for at the hospital between 2007 and 2016. Demographic, clinical data, microbiological characterization and outcomes at discharge, were analyzed.ResultsWe collected data for all 26 patients over a 10-year period (annual incidence of 1.78 per 100,000), with an incidence of bacteremia of 0.53 cases per 100,000 population per year. F. nucleatum and F. necrophorum were the most frequent isolations (53.8% and 38.5%, respectively). F. necrophorum was found to be associated with a younger population. Although we found no deaths attributable to Fusobacterium, 15 patients (57%) were found to have severe infections due to this pathogen, and 7 patients (26.9%) were admitted to the Intensive Care Unit (ICU). The only identifiable risk factor for a severe infection (sepsis, septic shock or ICU admission) was the presence of bacteremia.ConclusionsFusobacterium infections are uncommon. F. necrophorum tends to cause infection in younger individuals, while F. nucleatum has a preference for older patients. The clinical spectrum is wide, ranging from local, nonsevere infections, such as sinusitis or pharyngitis, to abscess formation and life-threatening infections.

is the oropharyngeal pathogen usually associated with Lemierre's syndrome, a pharyngeal infection which evolves to sepsis, septic emboli and thrombophlebitis of the adjacent neck vessels. It is an uncommon causative bacteria of a liver abscess, and an extensive workup should, therefore, be performed in order to rule out potential sources of the infection. This case report describes the workup that led to the diagnosis of a colorectal carcinoma, which was deemed to be the source of the bacteraemia.