Multiple periodontal abscesses after systemic antibiotic therapy.

Multiple periodontal abscesses were reported in medically compromised patients. We examined patients with a non-contributory medical history referred for the treatment of numerous periodontal abscesses. All patients had taken oral broad spectrum antibiotics 1 to 3 weeks prior to the outburst of the abscesses (8 patients: penicillin, 2 patients: tetracycline). The patients suffered from advanced periodontal disease, 82% of the examined sites showed probing depths greater than 3 mm, 56% attachment loss greater than 3 mm. Subgingival plaque samples were analysed from 2 different abscess sites. Bacteroides gingivalis (19/20), Fusobacterium nucleatum (13/20) and Streptococcus intermedius (13/20) were the most prevalent anaerobic microbiota. Strains resistant to the prescribed antibiotic were found in 55% (11/20) of the subgingival plaque samples. It was concluded that in patients with advanced periodontal disease, systemic antibiotic therapy without subgingival debridement may change the composition of the subgingival microbiota, thus favouring the outburst of multiple periodontal abscesses.