In-silico Analysis of the Genetic Diversity and Virulence Genes in Streptococcus species.

The present study investigates the virulence property of Streptococcus species through in silico tools. In silico polymerase chain reaction analyzed fifteen virulence genes. Studies revealed that lytA is an obligatory gene as all the Streptococcus pneumoniae isolates analyzed in this study had the autolysin genes, lytA. Twenty isolates (17.09%) had the pneumolysin gene, ply, which is expressed on the surface of pneumococci. Nineteen isolates (16.24%) carried pneumococcal surface protein A (pspA) gene that has anticomplementary property. Among the three genes of Streptococcus agalactiae, the bca gene (1.71%) was encountered at a lower frequency compared to cylE (5.98%) and sip gene (7.69%). Isolate Streptococcus uberis0140J expressed both streptokinase, skc and plasminogen activator, pauA gene which differentiates Streptococcus uberis from other Streptococcus species. The glucosyltransferase, gtfB genes were present in three isolates (2.56%). Glutamate dehydrogenase genes (gdh), a diagnostic marker of Streptococcus suis, were present in 11.9% (n=14) of the isolates. Thirteen isolates (11.11%) had the muramidase released protein (mrp) and suilysin (sly) gene. Streptococcal superantigen (ssa), streptococcal pyrogenic toxin A (speA) and streptococcal invasion locus (sil) genes were present in 2.56%, 5.98% and 3.42% isolates, respectively. In silico pulsed field gel electrophoresis was able to group isolates into 15 genotypes at 80% cutoff value. Genotype 8 was more prevalent (24.9%) and also carried 7 virulent genes. Genotype 9 and 10 harboured mainly pneumolysin and autolysin genes but glucosyltransferase genes, gtfB were also present. Six genotypes harboured no virulence gene. This virulence gene profile generated here aids us to understand the virulence gene associated with disease in relation to the genotypes.