Fusobacterial Infections: Clinical Spectrum and Incidence of Invasive Disease

Objectives: Clinically significant infections caused by members of the genus Fusobacterium are rare. We sought to describe the spectrum of clinical disease and epidemiology of these conditions presenting to an acute hospital over a five year period.

Methods: Clinical records relating to consecutive laboratory isolates of Fusobacterium species were reviewed and cases classified according to pre-specified definitions of primary site and invasive infection.

Results: 78 Fusobacterium isolates were identified, 25 of which were associated with invasive disease, most commonly in men (76% of cases). Invasive Fusobacterium necrophorum infection of the head and neck was not observed in patients over 50. Invasive intra-abdominal disease was not observed amongst those under 60. 2 cases of Fusobacterium nucleatum bacteraemia were identified in neutropenic children. One retroperitoneal abscess may have represented secondary infection due to periodontitis. Obstetric infections were the most common clinical syndromes associated with isolates from the female genital tract. The incidence of invasive head and neck disease in the population aged 15-50 was 6.7 per million/year. There were no deaths.

Conclusions: Invasive fusobacterial infections are rare, affect distinct patient groups and are associated with good clinical outcomes in the majority of cases.