Group a streptococcal infections of the pharynx in a rural population

Background & objectives: There has been a resurgence in the incidence of rheumatic heart disease all over the world and hence surveillance and strain characterization are important. The aim of this study was to screen children in a rural community in south India for throat carriage of group A streptococci and to clinically assess them for signs of rheumatic heart disease. Methods: Throat swabs were collected from children (5-14 yr) in the village of Orathur, Tamil Nadu and cultured on tryptose blood agar plates. Beta haemolytic streptococci were serogrouped using Streptex kit and biotyped based on their ability to ferment carbohydrates and production of b-glucuronidase enzyme. Blood samples were also collected and antibodies to streptolysin O demonstrated by latex agglutination tests. All the children were examined by a paediatrician; ECG and echocardiography were performed to assess cardiac function. Results: Eighty of the 310 children included in the study had symptoms of acute respiratory infections; 16 of them grew beta haemolytic streptococci of which 8 belonged to group A (10%). Biotype 4 was most common. Antistreptolysin O (ASO) test did not correlate with culture results. Two of 310 children had rheumatic heart disease but both were culture negative. Interpretation & conclusion: Pharyngeal carriage of group A streptococci was common in this population