Molecular characterization and evaluation of the emerging antibiotic-resistant Streptococcus pyogenes from eastern India.

BACKGROUND: Group A Streptococcus strains causing wide variety of diseases, recently became noticeable in eastern India, are not amenable to standard treatment protocol thus enhancing the possibility of disease morbidity by becoming antibiotic resistance.

METHODS: The association of Lancefield group A Streptococcal variation with degree of vir architectural diversity was evaluated using emm typing and restriction fragment length polymorphism analyses. The antibiotic sensitivity patterns were examined by modified Kirby-Bauer method of disk diffusion. Percentage calculations, 95% confidence interval and one-way ANOVA were used to assess differences in proportions.

RESULTS: Our observations revealed 20 different emm types and 13 different HaeIII vir typing patterns. A 1.2 kb fragment was found in all HaeIII typing pattern. Fragments of 1.2 kb and 550 bp were conserved in majority of the isolates. HinfI digestion was found proficient in differentiating the strains of same vir typing patterns. Strong predominance of speC (85%) and speF (80%) genes have been observed encoding exotoxins production. 4 isolates were found to be erythromycin resistant and were of genotype emm49. High degree of tetracycline resistance was shown by 53.57% isolates which belonged to 12 different emm genotypes.

CONCLUSIONS: These findings suggested that in addition to emm typing, sequential application of HaeIII and HinfI restriction enzymes in vir typing analysis is an effective tool for group A streptococcal molecular characterization associated with antibiotic resistance.