AUTHOR=Abdelbary Mohamed M. H. , Wilms Gerrit , Conrads Georg 

TITLE=A New Species-Specific Typing Method for Salivarius Group Streptococci Based on the Dephospho-Coenzyme A Kinase (coaE) Gene Sequencing

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.685657

DOI=10.3389/fcimb.2021.685657

ISSN=2235-2988

ABSTRACT=<p>Viridans streptococci are a group of α-hemolytic streptococcal species. They are mainly commensals, most abundant in the mouth supporting oral health. But they also include important human pathogens such as <italic>Streptococcus pneumoniae</italic>. Identification and molecular typing of viridans group streptococci are challenging, especially for members of the salivarius group. In this study, we developed a single-locus molecular typing method that is able to differentiate among the highly phylogenetically related members of the salivarius group (<italic>S. salivarius</italic>, <italic>S. vestibularis</italic> and <italic>S. thermophilus</italic>) and might support differentiation in other groups as well. This typing approach is based on the amplification and sequence analysis of the housekeeping gene dephospho-coenzyme A kinase (<italic>coaE</italic>), a gene with unrecognized taxonomic potential to date. Here, we analysed <italic>coaE</italic> gene sequences of 154 publicly available genomes and of 30 salivarius group isolates of our own collection that together belong to 20 different gram-positive bacterial (sub) species. Our results revealed that the <italic>coaE</italic> phylogeny distinguished between streptococcal and non-streptococcal genomes and that <italic>coaE</italic> gene sequences were species-specific. In contrast to MALDI-TOF MS performance, the <italic>coaE</italic> typing was able to precisely identify the phylogenetically very closely related members of the salivarius group.</p>