Penicillin Tolerance in Group a Streptococci and Treatment Failure in Streptococcal Tonsillitis

Abstract

Penicillin tolerance in Streptococcus pyogenes has been suggested as a possible cause of therapeutic failure in streptococcal phryngitis treated with penicillin. In 144 patients with acute group A streptococcal tonsillitis treated with phenoxymethyl penicillin 12.5 mg per kg body weight bid. for 10 days the same T-type was recovered after treatment in 21%. The recovery rate was higher for non-tolerant strains, 23%, than for tolerant strains, 10% (p >0.05). Of patients with a non-tolerant strain 17% had both clinical and bacterial treatment failure in comparison with 5% infected with a tolerant strain (p > 0.05). Reinfection with a new serotype occurred in altogether 3%. The present data did not indicate that penicillin tolerance in group A streptococci is of significance in acute tonsillitis treated with phenoxymethylpenicillin for 10 days.

Key Words:

• Streptococcus pyogenes
• treatment failure
• penicillin tolerance