Detection of group A streptococci in children under 3 years of age with pharyngitis

Abstract

Objective: To determine the frequency of group A streptococcal pharyngitis in young preschool children presenting to the emergency department with upper respiratory tract infection.

Methods: A prospective, observational study performed between September 1995 and September 1997. Throat swabs were obtained on young children less than 3 years old with pharyngeal erythema as well as age- and time-matched controls without pharyngeal erythema or exudate. Signs and symptoms that were recorded included: age, temperature, pharyngeal erythema, tonsillar exudate, cervical adenopathy, scarlatini-form rash, rhinorrhea, school-aged child in the home, day care attendance. Swabs were inoculated on 5% sheep blood agar and incubated for 48 hours. Beta-hemolytic colonies were sero-grouped by latex agglutination.

Results: Seventy-eight children with pharyngeal erythema, and 152 controls had pharyngeal specimens obtained and signs or symptoms recorded. Under 2 years of age, the detection of group A streptococci was similar to controls. Detection of group A streptococci was significantly different from controls in children over 2 years of age. Ten (29%) of 35 children over 2 years were positive for group A streptococci compared to 2 (7%) of 29 controls of the same age group (P = 0.03, odds ratio 5, 95% CI: 1.2-24). Findings on clinical examination in children with pharyngeal erythema did not distinguish those that would be culture-positive for group A streptococci.

Conclusion: In our emergency department, group A streptococci caused 30% of pharyngitis seen in children between 2 and 3 years of age. Diagnostic testing is recommended because physical examination may not accurately distinguish etiology in this age group.