The role of beta-lactamase-producing bacteria in the persistence of streptococcal tonsillar infection.

The failure of penicillin to eradicate group A beta-hemolytic streptococci (GABHS) is a growing problem. This review summarizes current data concerning the role of aerobic and anaerobic beta-lactamase-producing bacteria in the persistence of tonsillar infection caused by GABHS. Clinical studies have demonstrated the recovery of beta-lactamase-producing bacteria and detectable levels of the enzyme beta-lactamase in cultures of core tonsillar specimens in greater than 80% of the patients. The predominant bacteria have been Bacteroides melaninogenicus, Bacteroides oralis, Bacteroides ruminicola, and Staphylococcus aureus. These organisms have emerged in about one-third of patients after one course of penicillin therapy and can be transferred to patient's household contacts. These organisms were present in tonsillar cultures in higher numbers in children with acute tonsillitis who did not respond to penicillin therapy than in those who were cured. Protection of GABHS by beta-lactamase-producing organisms has been demonstrated in vitro and in vivo. Several studies, including a recent double-blinded study, have demonstrated the ability of clindamycin to eradicate the streptococcal carrier state and to prevent recurrent infection in selected patients.