Pan-genome analysis of invasive Streptococcus mutans strains

Streptococcus mutans is responsible for dental problems and is associated with cardiovascular co-morbidities. Only a few selected strains can adhere to and invade endothelial cells. To ascertain which strains have the capability to invade cardiovascular cells, in silico PCR was performed on all the 193 available strains. The genome sequences were screened for collagen-binding genes cnm and cbm. Among the 193 strains tested, only 4 showed the presence of collagen-binding gene. BPGA tool was used for pan-genome analysis of invasive strains. Results indicated an almost closed pan-genome for S. mutans comprising 45,654 core genes, 29,452 accessory genes and 232 unique genes. Most of the unique genes belonged to only 5 genomes amongst the 42 invasive genomes analysed. These five genomes were screened for the presence of virulence genes using the MP3 software. Protein-protein interactions between the pathogenic proteins and extracellular matrix components were analysed using HPIDB. Surface-localized proteins were predicted to interact with the human tumour suppressor gene.