Penicillin failure in streptococcal tonsillopharyngitis: causes and remedies

Synopsis. Penicillin administered for 10 days has been the treatment of cho ice for group A beta-hemolytic streptococcal tonsillopharyngitis since the 1950s, The bacteriologic failure rate of 10 days of penicillin therapy rang ed from approximately 2 to 10% until the early 1970s, Beginning in the late 1970s bacteriologic and clinical failure rates with penicillin therapy beg an to increase steadily over time and are now reported to be approximately 30%, The primary cause of penicillin treatment failure in streptococcal ton sillopharyngitis may be lack of compliance with the 10-day therapeutic regi men. Other causes of penicillin treatment failure include reexposure to Str eptococcus-infected family members or peers; copathogenicity, in which bact eria susceptible to a class of drugs are protected by other, colocalized ba cterial strains that lack the same susceptibility; antibiotic-associated er adication of normal protective pharyngeal flora; and penicillin tolerance, whereby streptococcal bacteria repeatedly or continuously exposed to sublet hal concentrations of antibiotic become increasingly resistant to eradicati on. Although 10 days of penicillin therapy is effective in the management o f tonsillopharyngitis for many patients, multiple factors may, singly or to gether, cause treatment failure. A number of antibiotics, particularly the cephalosporins, have been demonstrated to be superior to penicillin at erad icating group A beta-hemolytic Streptococcus, and several are effective whe n administered for 4 to 5 days. Conclusions. Ten days of penicillin therapy may not be the best therapeutic choice for all pediatric patients. Other antibiotics, shortened courses of the cephalosporins in particular, may be preferable in some cases.