Clinical appearance of orofacial infections of odontogenic origin in relation to microbiological findings.

Fifty-eight patients with acute orofacial infections of odontogenic origin were classified into two groups with respect to the severity of infection. A total of 174 anaerobic and 22 aerobic bacterial strains were isolated. Anaerobic gram-negative rods were isolated more frequently from the patients with severe infections than from the patients with infections judged as mild (P less than 0.05). The occurrence of Fusobacterium nucleatum especially appeared to be associated with the severity of the infections (P less than 0.05). Penicillin resistance among the anaerobes was rarely found, while resistance to erythromycin was a common finding. All aerobic and anaerobic bacteria were susceptible to clindamycin, and all obligate anaerobic bacteria were susceptible to nitroimidazoles.