Dapinder Kaur Bakshi, Vanita Dhanda, Vivek Sagar, Devinder Toor, Rajesh Kumar and Anuradha Chakraborti
Heterogeneity exists among Group a Streptococcus emm types worldwide. In 2003, we observed 11 circulating emm types in northern region of India, of which emm 81 was found to be the predominant type (17.5%). As emm 81 has been reported to be associated with invasive diseases in western countries, hence, in the present study, attempts were made to study the virulence potential of these isolates from skin and throat samples. Isolates were screened for nine fi bronectin binding protein (FBP) genes, evaluated for adherence & invasion potential along with drug resistance to various commonly prescribed antibiotics for treatment. Throat isolates showed higher distribution of FBP genes as compared to skin isolates. All the isolates were found to be positive for sciB and prtF15; 92.9% for sfb and fba, 78.6% for sciA; 35.2% for prtF1; 7.1% for prtF2 but none for sfb2 and pfbp. Isolates showed low (8.5%) to moderate (27.7%) adherence and negligible invasion potential in the experimental A549 cell line which was con firmed by immuno fluorescent confocal microscopy. Drug resistance pro fi ling showed isolates to be highly resistant to macrolides, tetracycline, co-trimaxazole but all susceptible to penicillin. The study shows emm 81 strains from northern India to be of less virulent nature with respect to adherence/invasion potential, highlighting that same emm type in different geographical regions may have a different clinical outcome, the latter being dependent on number of factors like ethnicity, geographical, socioeconomic factors besides its molecular type and source.