[Bacterial epidemiology of pharyngitis in pediatric private practice]

While viruses are usually the causal agents of common sore throat in children, bacterial infections cannot be distinguished solely on the basis of clinical presentation. Thus most physicians in France prefer to prescribe antibiotics in order to prevent rheumatismal complications of group A streptococcal infections. We updated current epidemiological data on bacterial pharyngitis in paediatric out-patient clinics.

A prospective study was conducted from March 1 to June 1, 1992 by 9 physicians. Throat swabs were obtained from 102 controls and from 307 patients with acute pharyngitis. Samples were transferred to the same bacteriology laboratory for examination.

The mean age of the children was 6.1 years for patients and 7.2 years for controls. Throat swabs were inoculated for culture within a mean delay of 22.6 hours. Cultures were performed on Columbia blood medium with nalidixic acid and colistin then incubated in CO2 enriched atmosphere and on trypticase blood soy medium + 3.5% NaCl. Group A streptococcal strains were identified by search for beta-haemolysis and latex characterisation of group A polyosides. Group A streptococcal strains were found in 8.8% of the controls and 36.8% of the patients. Groups B, C or G streptococci were found in 10.8 et 11.4% of the controls and patients respectively (NS). Arcanobacterium haemolyticum was never isolated. Clinical association of sore throat, erythematous pharyngitis, fever > 38 degrees C and cervical lymph nodes was found in only 33.63% of the sore throat cases with group A streptococcal infection and in 7.73% of those without group A streptococcal infection (p < 0.0001, sensitivity 33%, specificity 92%).

These results emphasize the necessity either to treat all pharyngitis or to do throat swabs or rapid group A streptococcal tests for diagnosis.