Prevalence and identification of tetracycline-resistant oral bacteria in children not receiving antibiotic therapy

The prevalence of tetracycline-resistant oral bacteria in healthy 4- and 6-year-old children who had not received antibiotics during the 3 months prior to sampling was investigated. Of the 47 children sampled, 46 harboured tetracycline-resistant bacteria. The median proportion of cultivable anaerobic and aerobic oral bacteria resistant to tetracycline was 1.1% and the MIC(50) of these was 64 mug ml(-1). The majority (56%) of tetracycline-resistant bacteria were resistant to at least one other antibiotic, usually erythromycin. The most commonly identified tetracycline-resistant bacteria were the oral streptococci (65%), the next most prevalent groups were Veillonella spp. (10%) and Neisseria spp. (9%). The most frequently identified tetracycline resistance determinant was tet(M). The results of this study have shown that tetracycline-resistant oral bacteria were widespread amongst the children studied. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Microbiological Societies.