International Journal of Systematic and Evolutionary Microbiology (2002), 52, 665–669 DOI : 10.1099/ijs.0.02012-0 NOTE Streptococcus entericus sp. nov., isolated from cattle intestine 1 Departamento de Patologı  a Animal I (Sanidad Animal), Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain 2 School of Food Biosciences, University of Reading, UK 3 Departamento de Patologı  a Animal, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain 4 Culture Collection, Department of Clinical Bacteriology, University of Go  teborg, Sweden A. I. Vela, 1 E. Ferna  ndez, 2 † P. A. Lawson, 2 M. V. Latre, 3 E. Falsen, 4 L. Domı  nguez, 1 M. D. Collins 2 and J. F. Ferna  ndez-Garayza  bal 1 Author for correspondence : J. F. Ferna  ndez-Garayza  bal. Tel: 34 91 3943716. Fax : 34 91 3943908. e-mail : garayzabvet.ucm.es Biochemical, molecular chemical and molecular genetic studies were performed on an unknown Gram-positive, catalase-negative, coccus-shaped organism isolated from the intestine of a cow affected with catarrhal enteritis. The organism was tentatively identified as a streptococcal species based on results of cellular morphological and biochemical tests. 16S rRNA gene sequencing studies confirmed its provisional identification as a member of the genus Streptococcus, but the organism did not correspond to any recognized species of this genus. The nearest phylogenetic relatives of the unknown coccus from a calf were Streptococcus acidominimus and Streptococcus suis. The unknown bacterium, however, was distinguished from these species and other animal streptococci by biochemical tests and electrophoretic analysis of whole-cell proteins. Based on both phenotypic and phylogenetic findings, it is proposed that the unknown bacterium be classified as a novel species of the genus Streptococcus, Streptococcus entericus sp. nov. The type strain is CECT 5353 T ( CCUG 44616 T ). Keywords : Streptococcus entericus sp. nov., taxonomy, phylogeny, 16S rRNA Molecular genetic methods, most notably 16S rRNA gene sequencing, have contributed greatly to improve- ments in the taxonomy of the genus Streptococcus. In particular, phylogenetic analysis based on comparative 16S rRNA analysis has helped to clarify the intra- generic relationships of the streptococci (Bentley et al., 1991 ; Kawamura et al., 1995 ; Hardie & Whiley, 1997) and has aided the recognition of a plethora of novel species from human (e.g. Kawamura et al., 1998 ; Flint et al., 1999 ; Collins et al., 2000 ; Schlegel et al., 2000), animal (e.g. Devriese et al., 1997, 1999 ; Rurangirwa et al., 2000) and food (e.g. Tsakalidou et al., 1998; Schlegel et al., 2000) sources. Although streptococci can be isolated as part of the normal flora of the alimentary, respiratory and genitourinary tracts, as well as the skin of man and different animals (Kilian, 1998), some species are established pathogens that cause a variety of diseases such as endometritis, res- piratory infections, endocarditis, meningitis, arthritis and mastitis (Chanter, 1997). Streptococcus bovis, ................................................................................................................................................. † Present address : Departamento de Patologı  a Animal I (Sanidad Animal), Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain. The GenBank accession number for the 16S rRNA gene sequence of strain CCUG 44616 T is AJ409287. Streptococcus intestinalis ( junior synonym of Strep- tococcus alactolyticus) and Streptococcus thoraltensis have been isolated from or are members of the intestinal flora of different animals (Devriese et al., 1997 ; Kilian, 1998 ; Vandamme et al., 1999), but their association with pathological processes is not clear. Although there are some reports of intestinal disorders associated with streptococci (Bard et al., 1987 ; Jergens et al., 1991 ; Gelshorn et al., 1994 ; Willard et al., 1998 ; Svane, 2000), enteric disease associated with this group of organisms remains poorly defined. During the course of a study of a cow affected by catarrhal enteritis, we have isolated a Gram-positive, catalase- negative, coccus-shaped organism that resembles the streptococci. We report the results of a polyphasic taxonomic study on the isolated coccus. Based on the findings presented, a novel streptococcal species, Streptococcus entericus sp. nov., is described. A diarrhoeic process affecting thirty, 7- to 10-day-old Holstein–Friesian calves of the same farm was investi- gated. Catarrhal enteritis was the clinical sign observed after post-mortem examination of one diseased ani- mal. Gram stain of faeces and the mucous membrane of the jejunum revealed the presence of large numbers of Gram-positive, ovoid-shaped bacteria. A coccus- 02012  2002 IUMS Printed in Great Britain 665