The role of the carrier in treatment failures after antibiotic for group A streptococci in the upper respiratory tract

J Lab Clin Med. 1981 Sep;98(3):326-35.


During a prospective study of endemic group A streptococcal upper respiratory tract infection and the streptococcal carrier state, we investigated persistence of group A streptococci after treatment with recommended doses of antibiotics. We evaluated clinical findings, culture results, and streptococcal antibody responses at the acute-stage clinic visit and at convalescent-stage visits 3 and 8 weeks later. Data from 280 children ill with pharyngitis and their family contacts were analyzed (mean age 13.3 years); 129 individuals (46%) had group A beta-hemolytic streptococci isolated at the initial visit. Despite antibiotic treatment, group A streptococci were not eradicated from the upper respiratory tract of 34 (26%) of the 129 culture-positive individuals. Thirteen of the 34 (38%) required a second course of antibiotic therapy before the infecting serotype was eradicated, but a majority, the remaining 21 (62%) patients, were not bacteriologically cured despite repeated courses of antibiotics. Streptococcal antibody data suggested that the majority of the treatment failures were streptococcal carriers. Only 5% of asymptomatic individuals with a positive culture for group A streptococci demonstrated an antibody rise. These bacteriologic and serologic data document that it usually is unnecessary to retreat asymptomatic convalescent individuals having throat cultures persistently positive for group A streptococci, since these individuals seldom represent true streptococcal infection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / therapeutic use*
  • Antibodies, Bacterial / immunology
  • Antibody Formation
  • Bacteriological Techniques
  • Blood Sedimentation
  • C-Reactive Protein / analysis
  • Carrier State / physiopathology*
  • Child
  • Child, Preschool
  • Humans
  • Infant
  • Respiratory Tract Infections / drug therapy*
  • Streptococcal Infections / drug therapy*
  • Streptococcus pyogenes / drug effects*


  • Anti-Bacterial Agents
  • Antibodies, Bacterial
  • C-Reactive Protein