STREPTOCOCCUS-PERORIS SP. NOV. AND STREPTOCOCCUS-INFANTIS SP. NOV., NEW MEMBERS OF THE STREPTOCOCCUS-MITIS GROUP, ISOLATED FROM HUMAN CLINICAL SPECIMENS

Taxonomic studies were performed on eight strains of a-haemolytic stre ptococci that showed very low DNA-DNA hybridization similarity values with all established members of the mitis group of the genus Streptoco ccus. These strains were isolated from the tooth surface and pharynx o f humans. 16S rRNA gene sequence analysis showed that these strains be longed to the mitis group, but that they fell into two new branches. D NA-DNA hybridization demonstrated two new similarity groups. From the results of the present study, the names Streptococcus peroris sp. nov. and Streptococcus infantis sp. nov. are proposed for these new groups . The type strains are 0-66(T) (= GTC 848(T) = JCM 10158(T)) and 0-122 (T) (= GTC 849(T) = JCM 10157(T)), respectively.