Oral streptococcal bacteremia in hospitalized patients: taxonomic identification and clinical characterization

Abstract

Oral streptococci have been associated with systemic diseases, including infective endocarditis and neutropenic bacteremia. We analyzed 58 recent oral streptococcal bloodstream isolates, and we obtained clinical and demographic data for source patients. The sodA gene was found to be a better target than the 16S-23S rRNA internal transcribed spacer for DNA sequence-based species identification. Together, Streptococcus mitis and Streptococcus oralis were significantly more likely than the 12 combined remaining species to be isolated from neutropenic patients.

Fig 1

Neighbor-joining trees for ITS and sodA sequences. Clinical isolates are indicated by VMC number and final species assignment. Fill colors correspond to patient underlying illness, and red outlines indicate reference strains. The scale indicates the number of base substitutions per site, with distances determined using the maximum composite likelihood method (21). Bootstrap values that were equal to or greater than 50% from 2,000 replicates are indicated in blue text adjacent to the branches. *, isolate for which additional sequences (pfl and/or pyk) were determined.