Multicenter clinical evaluation of the illumigene group A Streptococcus DNA amplification assay for detection of group A Streptococcus from pharyngeal swabs.

[acute rheumatic fever]

Acute pharyngitis is a nonspecific symptom that can result from a number of viral or bacterial infections . For most etiologies , symptoms are self-limited and resolve without lasting effects ; however , pharyngitis resulting from infection with Streptococcus pyogenes (a group A Streptococcus [GAS ]) can be associated with serious sequelae , including acute rheumatic fever and acute glomerulonephritis . Rapid accurate detection of GAS in pharyngeal specimens from individuals suffering from pharyngitis aids in the management and selection of antibiotic therapy for these patients . A total of 796 pharyngeal swabs were collected at three separate clinical centers . Each specimen was analyzed using the illumigene group A strep DNA amplification assay (Meridian Bioscience Inc ., Cincinnati , OH ). To confirm GAS identification , the results were compared to those from direct and extracted culture methods using Gram staining and a GAS -specific latex agglutination test . Discrepant results were resolved using an alternative nucleic acid amplification test . The prevalence of culture-detected GAS in this study was 12 .8 % (102 /796 specimens ). The illumigene assay detected GAS in 74 /74 direct culture-positive specimens (100 % sensitivity ) and 100 /102 extracted culture-positive specimens (98 .0 % sensitivity ). GAS was detected by the illumigene assay in an additional 42 specimens that were direct culture negative (94 .2 % specificity ) and 16 specimens that were extracted culture negative (97 .7 % specificity ). Discrepant analysis using an alternative molecular assay detected GAS nucleic acid in 13 /16 (81 .3 %) false-positive specimens and 1 /2 false-negative specimens , resulting in a final sensitivity of 99 .0 % and a specificity of 99 .6 % for the detection of GAS in pharyngeal swabs using the illumigene assay .