Impact on peritonsillar infections and microflora of phenoxymethylpenicillin alone versus phenoxymethylpenicillin in combination with metronidazole.

In a double-blind study, 20 patients with peritonsillar abscesses were treated with 2 g phenoxymethylpenicillin b.i.d. for ten days together with needle aspiration, incision and daily drainage, and 20 patients were treated with 2 g phenoxymethylpenicillin b.i.d. and 0.8 g metronidazole b.i.d. for ten days together with needle aspiration, incision and daily drainage. Group A beta-hemolytic streptococci were isolated from pus in 20 of the patients with peritonsillar abscesses, in five of these together with indigenous oropharyngeal aerobic and anaerobic microorganisms. Pure anaerobic bacteria were found in nine abscesses, together with indigenous aerobic microorganisms in eight, and together with group A, C and G streptococci in five. In one patient heavily colonized with beta-lactamase-producing Staphylococcus aureus, Haemophilus parainfluenzae and Bacteroides, group A beta-streptococci failed to be eradicated. In the penicillin group, nine of 18 patients harboured beta-lactamase producing Bacteroides strains in the tonsils on the day of admission. On the third and tenth days of treatment all patients harboured beta-lactamase producing Bacteroides strains in the tonsils, while in the penicillin + metronidazole group, only one out of 17 patients still harboured beta-lactamase producing Bacteroides strains. None of the patients harboured beta-lactamase producing fusobacteria on the day of admission. In the penicillin group, however, beta-lactamase producing fusobacteria were recovered from three patients on the tenth day of treatment. No beta-lactamase producing fusobacteria were recovered from the penicillin + metronidazole group.(ABSTRACT TRUNCATED AT 250 WORDS)