Colonization rate of bacteria in the throat of healthy infants

Objective: the human throat is a major ecological site for various bacteria that can reach neighbouring sterile sites and cause mild infections or invasive diseases. The aim of this study was to investigate the carriage rate of several potential pathogens in the throat of healthy children under the age of 2 years. Methods: cultures were taken from the tonsils of 1000 healthy infants aged 1-24 months attending well-baby clinics, who had not received antibiotic therapy during the preceding 14 days. Results: one hundred and ninety-eight (19.8%) cultures were positive. Thirteen (1.3%) cultures were positive for β-haemolytic Streptococcus group A, 23 (2.3%) for Streptococcus pneumoniae. In 28 (2.8%) and 24 (2.4%) cultures, respectively, Haemophilus influenzae Type b and non-typeable Haemophilus influenzae were recovered. The commonest bacterium found was Staphylococcus aureus (99 positive cultures). Eleven children carried two species of bacteria and from one 6-month-old child three species were isolated concurrently. Conclusions: it is concluded that children younger than 2 years of age can be carriers of several types of pathogenic bacteria. In contrast to many other studies, in this study β-haemolytic Streptococcus group A was isolated from the tonsils of children younger than 1 year of age.