The prevalence of beta-haemolytic streptococci in throat specimens from healthy children and adults: Implications for the clinical value of throat cultures

Objective-To examine the influence of age and season of the year on the carrier rate of beta-haemolytic streptococci (BHS) in healthy individuals and patients with throat pain.Design-The prevalence of BHS in throat specimens from healthy individuals was compared with that from patients with throat pain of the same age in a defined geographical area, collected during the same mid-winter and late summer periods.Results-The prevalence of BHS in healthy individuals was low before the age of 3 years (1.9-7.1%) and in adults ≥16 years (2.4-3.7%) and highest in the age group 3-15 years (5.0-21.2%). The difference in prevalence of BHS between healthy individuals and patients with throat pain was small during the late summer season and large during the mid-winter season.Conclusion-Prevalence of BHS varies with age and season in healthy individuals and patients with throat pain. During the summer, it is much more difficult to interpret the result of a throat culture in individuals aged <16 years.