Draft genome sequencing of biofilm-forming Streptococcus constellatus

Abstract

Streptococcus constellatus, a member of the anginosus group streptococci, is commonly associated with oral abscesses, bacteremia with subsequent septic shock, and brain abscesses. We isolated S. constellatus strain H39 from an apical abscess lesion. Scanning electron micrographs revealed that strain H39 had dense meshwork-like structures around the cells, which are a characteristic of biofilm-forming bacteria. In this study, we reported a draft genome sequencing of strain H39 which can be used for further genetic study on biofilm formation mechanisms. The genome sequencing was performed by pyrosequencing. The putative gaps between contigs were closed by sequencing of polymerase chain reaction amplicons over the gaps. A high-quality draft genome sequence indicated that strain H39 had 3 ribosomal RNA genes, 45 transfer RNA genes and 1,926 putative protein-coding genes. We also found that strain H39 possessed genes encoding exopolysaccharide biosynthesis proteins and ABC-type polysaccharide transport proteins. These genes might contribute to the biofilm formation of S. constellatus strain H39.