| Title | Analysis of phylogenetic markers for classification of a hydrogen peroxide producing Streptococcus oralis isolated from saliva by a newly devised differential medium |
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| Author | Ha Pham1, Thi Dieu Thuy Tran1, Youri Yang2, Jae-Hyung Ahn3, Hor-Gil Hur2*, and Yong-Hak Kim1* |
| Address | 1Department of Microbiology, Daegu Catholic University School of Medicine, Daegu 42472, Republic of Korea, 2Applied and Environmental Microbiology Laboratory, School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea, 3Bioremediation Team, National Institute of Agricultural Science, Rural Development Administration, Wanju 55365, Republic of Korea |
| Bibliography | Journal of Microbiology, 60(8),795-805, 2022, |
| DOI | 10.1007/s12275-022-2261-2 |
| Key Words | H2O2-producing Streptococcus, morphological and genetic heterogeneity, o-dianisidine dye, ROS scavenging proteins, Saliva |
| Abstract | Hydrogen peroxide (H2O2) is produced by alpha-hemolytic streptococci in aerobic conditions. However, the suitable method for detection of H2O2-producing streptococci in oral microbiota has not been setup. Here we show that o-dianisidine dye and horseradish peroxidase were useful in tryptic soy agar medium to detect and isolate H2O2-producing bacteria with the detection limit of one target colony in > 106 colony-forming units. As a proof, we isolated the strain HP01 (KCTC 21190) from a saliva sample using the medium and analyzed its characteristics. Further tests showed that the strain HP01 belongs to Streptococcus oralis in the Mitis group and characteristically forms short-chain streptococcal cells with a high capacity of acid tolerance and biofilm formation. The genome analysis revealed divergence of the strain HP01 from the type strains of S. oralis. They showed distinctive phylogenetic distances in their ROS-scavenging proteins, including superoxide dismutase SodA, thioredoxin TrxA, thioredoxin reductase TrxB, thioredoxin-like protein YtpP, and glutaredoxin- like protein NrdH, as well as a large number of antimicrobial resistance genes and horizontally transferred genes. The concatenated ROS-scavenging protein sequence can be used to identify and evaluate Streptococcus species and subspecies based on phylogenetic analysis. |