Betalactamase-producing microorganisms in recurrent tonsillitis.

In 73% of 167 patients with recurrent tonsillitis, colonization with betalactamase-producing microorganisms was found. Betastreptococci group A were recovered in 6% of the patients and group C and G streptococci in 23%. Other microorganisms found were Staphylococcus aureus in 42%, Haemophilus species in 52%, bacteroides species in 80% and fusobacteria in 40%. Ninety-eight per cent of Staph. aureus, 60% of bacteroides species and 10% of fusobacteria were betalactamase-producing. Phenoxymethylpenicillin (1 g twice a day for ten days) diminished 50% of group A, C and G streptococci. No other microorganisms were affected by this antibiotic. Clindamycin (0.15 g four times a day for ten days) eradicated Staph. aureus, group A, C and G streptococci, bacteroides and fusobacteria. Haemophilus species were not affected by clindamycin. Tinidazole (1 g once a day for 10 days) diminished bacteroides and fusobacteria. Aerobic microorganisms, Staph. aureus, streptococci and Haemophilus, were not affected by tinidazole.