McIsaac Modification of Centor Score in Diagnosis of Streptococcal Pharyngitis and Antibiotic Sensitivity Pattern of Beta-hemolytic Streptococci in Chennai, India

Abstract

To assess the validity of modified Centor Score in predicting streptococcal pharyngitis, and describe the antibiotic sensitivity of streptococcal strains. A cross-sectional study of 120 children (age 1-18 y) with signs and symptoms of pharyngitis was undertaken in the pediatric department of a tertiary care teaching hospital in Chennai from July 2015 to April 2016. Modified Centor score was calculated for all children, and streptococcal sore throat was confirmed by throat swab culture. Predictive validity of Centor score was assessed by Receiver Operating Curve (ROC) analysis. Streptococcal culture positivity was 35%. The Area Under the Curve (AUC) value for modified Centor score was 0.589 (95% CI 0.481 to 0.697, P=0.11) in predicting streptococcal pharyngitis. Cough had the highest sensitivity (63.4%), but poor specificity (36.7%) for streptococcal pharyngitis confirmed by culture. The specificity was 100% for palatine petechiae, followed by palatine exudates (97.5%) and tender anterior cervical nodes (88.6%) to diagnose streptococcal pharyngitis. The proportion of antibiotic resistance was highest for cotrimoxazole (16.7%). Predictive validity of modified Centor score was not satisfactory, and resistance to cotrimoxazole, fluoroquinolones and macrolides was high among S. pyogenes strains.