Severe versus local odontogenic bacterial infections: comparison of microbial isolates

It was the aim of this study to evaluate the clinical and microbiological differences between severe and local odontogenic abscesses.

Thirty patients were prospectively enrolled. Sixteen of 30 patients suffered from a severe life-threatening abscess of the head and neck, whereas 14/30 patients presented with a localized submucous abscess. Anaerobic bacteria were identified and susceptibility testing was performed using E test strips for penicillin, amoxicillin + clavulanic acid, imipenem + cilastatin, clindamycin and metronidazole.

The mean duration until removal of all drains was 14.1 and 3.5 days, respectively. Anaerobic bacteria were found in all episodes of local abscesses, whereas 19% of the severe episodes were culture negative, and in 13%, only aerobes were identified. A total of 60 anaerobes were isolated from 27 patients (2.2 isolates/positive sample). The dominating species were Prevotella sp. (n = 17), Peptostreptococcus sp. (n = 15) and Propionibacterium sp. (n = 5). Eighty-seven percent of the isolates were susceptible to penicillin. Ninety-seven percent of the anaerobes were susceptible to amoxicillin + clavulanic acid, imipenem + cilastatin, and clindamycin. Eighty-three percent were susceptible to metronidazol. There was a tendency for a higher rate of episodes with penicillin-resistant bacteria in the patients with severe abscesses (14 vs. 31%). No difference in susceptibility regarding amoxicillin + clavulanic acid and clindamycin (7%) was observed.