NEW YORK (Reuters Health) - In kids with repeat throat infections, removal of the tonsils and adenoids, an operation known as adenotonsillectomy, can reduce levels of potentially harmful bacteria growing in the back of the throat, new research shows. Still, this may not mean a reduction in future throat infections.

The study involved 300 children, between 2 and 8 years of age, who were randomly selected to undergo adenotonsillectomy or to receive careful follow-up. The findings are reported in the Archives of Otolaryngology -- Head and Neck Surgery.

Throat swabs were taken at the start of the study and again 3 and 12 months later to see if levels of harmful bacteria had changed, note Dr. Anne G. M. Schilder, from University Medical Center Utrecht in the Netherlands, and colleagues.

Treatment with adenotonsillectomy was associated with reduced levels of three disease-causing microbes at 3 and 12 months: Haemophilus influenzae, group A beta-hemolytic streptococci, and Staphylococcus aureus. In fact, there was no evidence of the latter two microbes at either point.

In the follow-up comparison group, by contrast, the presence of these microbes did not change during the study period.

However, the presence of a particular microbe doesn't necessarily translate into more throat infections. For instance, in the surgery group and the comparison group, group A beta-hemolytic streptococci did not affect the occurrence of repeat throat infections, Schilder told Reuters Health.

Questions to be answered in future studies, she added, include "what factors predispose children to (repeat throat infections and) can we recognize at an early stage which children are likely to benefit more or less from surgery?"