Streptococcus lactarius sp. nov., isolated from breast milk of healthy women.
Three strains of a hitherto-unknown, Gram-stain-positive coccus were recovered from the milk of three non-related healthy women. The isolates shared 99 % 16S rRNA gene sequence similarity with sequences from uncultured members of the Lactobacillales and Streptococcus. The closest sequence corresponding to a defined species was that of Streptococcus peroris GTC 848(T), with a similarity of 98 %. A partial sequence (488 bp) of the tuf gene also showed 97 % similarity with that of S. peroris CCUG 39814(T). The combined 16S rRNA/tuf-based phylogeny revealed that all the isolates grouped in a statistically well-supported cluster separate from S. peroris. Enzyme activity profiles as well as fermentation patterns differentiated the novel bacteria from other members of the Streptococcus mitis group. Finally, phenotypic, genotypic and phylogenetic data supported the proposal of a novel species of the genus Streptococcus, for which the name Streptococcus lactarius sp. nov. is proposed. The type strain is MV1(T) ( = CECT 7613(T)  = DSM 23027(T)).
Martín
Virginia
V
Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Mañes-Lázaro
Rosario
R
ENOLAB-Laboratorio de Microbiología Enológica, Departamento de Microbiología y Ecología, Facultad de Biología, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
Rodríguez
Juan Miguel
JM
Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Maldonado-Barragán
Antonio
A
Departamento de Biotecnología de Alimentos, Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, 41012 Sevilla, Spain.|Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013291:Streptococcus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S