Introduction: Antimicrobial resistance is on the increase in 'medical and dental fields. Beta-lactam antibiotics are the most widely used antimicrobials in dental patients.
Objectives: This study investigated the prevalence of beta-lactamase-producing anaerobic oral bacteria in patients with chronic periodontitis.
Methods: Pooled subgingival samples from two sites in 42 patients with chronic periodontitis were cultured anaerobically on blood agar plates containing amoxycillin or/and Augmentin. Colonies that grew on amoxycillin but not Augmentin were identified and tested for beta-lactamase production.
Results: Sixty-nine percent of patients carried beta-lactamase-producing anaerobes, with a mean of one to two strains per patient. Seventy isolates of the beta-lactamase- producing strains formed 4% of the total cultivable anaerobic flora. Prevotella was the most prevalent beta-lactamase-producing species, followed by Capnocytophaga, Veillonella and Bacteroides.
Conclusions: A high prevalence of beta-lactamase-producing oral anaerobes was detected in this preliminary study. However, the percentage of beta-lactamase producers in the total number of bacteria per patient was low. Therefore, beta-lactam antibiotics still remain the drug of choice in infections with odontogenic origin.