Streptococcus equi subsp. ruminatorum subsp. nov., isolated from mastitis in small ruminants

Abstract

Six isolates of an unknown Gram-positive, catalase-negative, chain-forming, coccus-shaped organism isolated from ovine and caprine mastitis were characterized by phenotypic and molecular taxonomic methods. On the basis of cellular morphology and the results of biochemical tests, the organism was tentatively identified as a streptococcal species. Comparative 16S rRNA gene sequencing studies confirmed that the organism is a member of the genus Streptococcus, with Streptococcus equi as its closest phylogenetic relative (98?8 % similarity). DNA-DNA pairing studies showed that the unidentified organism displayed more than 70 % relatedness to the type strains of S. equi subsp. equi and subsp. zooepidemicus. Despite the relatively high DNA-DNA reassociation values, biotyping and ribotyping allowed clear differentiation of the unknown bacterium from the two recognized subspecies of S. equi. On the basis of phenotypic and molecular genetic evidence, it is proposed that the unknown Streptococcus isolates from ovine and caprine mastitis be classified as a novel subspecies, Streptococcus equi subsp. ruminatorum subsp. nov. The type strain is CECT 5772 T (=CCUG 47520 T =Mt 167 T ).Mastitis is one of the most serious economic and health problems of small ruminant flocks worldwide (Las Heras et al., 1999). Streptococci, together with staphylococci, are the most prevalent micro-organisms responsible for mastitis in small ruminants (Menzies & Ramanoon, 2001). The main species of streptococci causing mastitis are Streptococcus agalactiae, Streptococcus dysgalactiae and Streptococcus uberis (Quinn et al., 1999), although unusual cases of mastitis caused by other species of streptococci such as Streptococcus equi subsp. zooepidemicus or Streptococcus parasanguinis have also been described (Fernández-Garayzábal et al., 1998a;Las Heras et al., 2002). The taxonomy of the genus Streptococcus has improved greatly in recent years as a result of the use of molecular chemical and genetic methods. In particular, the increased use of comparative 16S rRNA gene sequencing has clarified the identification of many taxonomically problematic or aberrant strains and has played a central role in the recognition of many novel streptococcal species, especially those from animals (Skaar et al., 1994;Devriese et al., 1997Devriese et al., , 1999Rurangirwa et al., 2000;Collins et al., 2002;Vela et al., 2002). During the course of a study of bacteria associated with mastitis in small ruminants, we have isolated, from different animals, six strains of Grampositive, catalase-negative, chain-forming cocci of uncertain taxonomic position. In this article, we report the results of phenotypic and molecular genetic studies of the taxonomy of these Streptococcus-like organisms. On the basis of the findings presented, we describe a novel subspecies of S. equi, Streptococcus equi subsp. ruminatorum subsp. nov.During a routine bacteriological survey to determine the aetiological agents of mastitis in small ruminants, six unidentified isolates were recovered from mas...

What’s new in bacteriology of the mare’s genital tract

“…equi (SEE), and ssp. ruminatorum (Fernandez et al, 2004). The species S. equi and S. dysgalactiae consisting of two subspecies ssp.…”

Streptococcus e gêneros relacionados como agentes etiológicos de mastite bovina

“…Mais recentemente, uma nova subespécie, Streptococcus equi subesp. ruminatorum, isolada de casos de mastite caprina e ovina, foi proposta por Fernandez et al [25].…”

“…Streptococcus iniae é um patógeno zoonótico, responsável por infecções graves e invasivas em vários tipos de peixes e em seres humanos [22,46]. Fernandez et al [25] propuseram a designação de S. equi subsp. ruminatorum como uma nova subespécie, com base na biotipagem fenotípica e métodos taxonômicos moleculares (seqüenciamento do gene 16S rRNA, estudos de pareamento DNA-DNA e ribotipagem).…”

FatalStreptococcus equisubsp.ruminatorumInfection in a Man

“…S. equi subsp. ruminatorum was described in 2004 in domestic sheep and goats with mastitis ( 3 ). More recently, it was isolated during severe infections in spotted hyenas and zebras ( 10 ).…”