Researchers Sequence Highly Cariogenic Streptococcus sobrinus Pathogen

The genomes of three strains of Streptococcus sobrinus, one of the most harmful bacteria known to accelerate the development of caries in certain individuals, have been successfully sequenced by University of Illinois at Urbana-Champaign’s College of Bioengineering researchers. The study, “Complete Genome Sequences of Streptococcus sobrinus SL1 (ATCC 33478 = DSM 20742), NIDR 6715-7 (ATCC 27351), NIDR 6715-15 (ATCC 27352), and NCTC 10919 (ATCC 33402),” was published in ASM Journals.

S. sobrinus has been difficult to sequence, as it is not present in all people; in addition, it is more difficult to work with in the lab — unlike Streptococcus mutans, which is more prevalent and was sequenced in 2002. “Compared to S. mutans, S. sobrinus produces acid more quickly and is associated with the poorest clinical outcomes, especially among children,” notes Paul A. Jensen, PhD, research team leader and an assistant professor from the Carl R. Woese Institute for Genomic Biology.

According to the team, a patient’s caries risk increases dramatically when both S. sobrinus and S. mutans are present. Sequencing the bacteria will allow researchers to build computational models to better understand how the two species interact. In addition, a key discovery was that S. sobrinus lacks complete pathways for quorum sensing, which would allow the microbe to sense and react to nearby bacteria and, thus, proliferate more efficiently. This knowledge may lead to better methods for managing the pathogen.