Fusobacterium necrophorum as an Emerging Pathogen of Acute Mastoiditis

Background: Recent reports have reported an increase in the incidence of acute mastoiditis because of Fusobacterium necrophorum. However, the crude incidence and the specific clinical and laboratory characteristics of F. necrophorum mastoiditis in children have not been described. Our aim was to describe these features to identify high-risk patients. Methods: The electronic medical records of all children with acute mastoiditis at a tertiary medical center between July 2011 and December 2015 were analyzed. Using a stepwise logistic regression to identify independent risk factors for F. necrophorum, we formulated a predictive model. Results: F. necrophorum was identified in 13% (19/149) of mastoiditis cases with an identifiable agent. Its incidence increased 7- fold from 2.8% in 2012 to 20.4% in 2015 (P = 0.02). F. necrophorum infection had unique clinical, laboratory and prognostic features. The vast majority had complications and underwent surgical intervention. The predictive model used 4 parameters to define high- risk patients for F. necrophorum infection at admission: females, winter/spring season, prior antibiotic treatment and a C-reactive protein value > 20 mg/dL (area under receiver operating characteristic curve 0.929). Conclusions: Clinicians should be aware of the increasing incidence of F. necrophorum mastoiditis and consider anaerobic cultures and specific anaerobic coverage in high- risk patients.