Tolerance and efficacy of interfering alpha-streptococci in recurrence of streptococcal pharyngotonsillitis: a placebo-controlled study

A total of 342 patients with clinical signs of tonsillitis and suspected gr oup A beta-haemolytic streptococci (GAS) aetiology verified with rapid test and GAS culture, were enrolled in a randomized, placebo-controlled double- blind, multicentre study. They received antibiotic treatment for 10 days, f ollowed by 10 days of alpha-streptococcal or placebo spray treatment in the ratio of 2 : 1. Pharyngeal status, throat culture and adverse events were investigated up to 75 days after treatment. The frequency of bacteriologica lly verified clinical recurrence was 13% in the alpha-streptococcal group a nd 15% in the placebo group at the follow-up on day 22. The corresponding f igures at the last valid visit after 45-75 days were 19% and 30%, respectiv ely, a statistically significant difference (p = 0.037). Furthermore, at th e last valid visit 5% of subjects in the alpha-streptococcal and 12% in the placebo group were healthy carriers bacteriological treatment failures, of GAS (p = 0.029). Treatment with alpha-streptococci and placebo spray were equally well tolerated. Thus re-colonization with alpha-streptococci seem t o hinder late recurrences of GAS pharyngotonsillitis.