Deoxyribonucleic Acid Relatedness of Strains of Yellow-Pigmented, Group D Streptococci

Abstract

Deoxyribonucleic acid (DNA) homalogy was used to examine genetic relatedness among 25 yellow-pigmented strains of group D streptococci and to clarify the possible genetic relatedness of these strains to Streptococcus faecium and Streptococcus faecalis. In all cases, the DNA of the yellow-pigmented strains hybridized with the DNA of S. faecium and S. faecalis at a level of less than 25%. Based on median thermal dissociation temperatures (Tm's) and hybridization tests, the yellow-pigmented strains were divided into two groups (I and 11). DNAs of strains in group I had relatively low Tm's and did not exhibit significant homology with DNA of the herein designated type strain (ATCC 25788) of S. faecium subsp. casseliflavus. The DNAs of group I1 strains, on the other hand, exhibited high Tm'S and had a high degree of homology with the DNA of the type strain of the above-mentioned subspecies. Three physiological traits were found to be peculiar to group I1 organisms: ability to grow in the presence of 6.5% sodium chloride, inability to ferment sorbitol, and inability to decarboxylate tyrosine. It is proposed that the group I1 strains constitute a separate and distinct species. Because the strains presently placed in this species include the type strain of S. faecium subsp. casseliflavus Mundt and Graham, the name of this species, according to the rules of the Bacteriological Code, is Streptococcus casseliflavus (Mundt and Graham) comb. nov.Mundt and Graham (11) proposed the name Streptococcus faecium subsp. casseliflavus for group D yellow-pigmented streptococci which were isolated from plants (11, 12). Taken into consideration for the establishment of this subspecies were its pigmentation, physiology, and ecology, which set this subspecies apart from Streptococcus faecalis and the other subspecies of Streptococcus faecium.

Deoxyribonucleic Acid Relatedness Among Major Human Enterococci

“…These values were calculated from melting temperatures of 84.2, 84.4, and 84.1"C, respectively. Other workers have reported similar values (12,16). The DNAs of all strains of enterococci were tested against the DNAs of the labeled American Type Culture Collection type strains of S .…”

Use of Penicillin-binding Proteins for the Identification of Enterococci

“…However, there have been reports in the literature concerning uncertainty in the classification of some species (see Bridge & Sneath, 1983;Jones, 1978;Mundt & Graham, 1968) and sub-species (Deibel, 1964;Jones et al, 1972). Studies using DNA composition (Farrow et al, 1983), DNA-DNA hybridization under optimal and stringent conditions (Bridge & Sneath, 1982;Farrow et al, 1983;Vaughan et al, 1979), rRNA-DNA hybridization (Garvie & Farrow, 198 1 ;Kilpper-Balz et al, 1982;Schleifer & Kilpper-Balz, 1984), lipid composition (Farrow & Collins, 1985), and analysis of isoprenoid quinones (Collins & Jones, 1979), have contributed to a better understanding of enterococcal species. Moreover, analysis of the penicillin-binding proteins (PBPs) in strains of Enterococcus faecalis and E. faecium showed that there were species-specific patterns of these cytoplasmic membraneassociated proteins (Williamson et al, 1983).…”

The combinations Lysobacter enzymogenes subsp. enzymogenes Christensen and Cook 1978, L. enzymogenes subsp. cookii Christensen 1978 and Streptococcus casseliflavus (Mundt and Graham 1968) Vaughan et al. 1979 were in accordance with the International Code of Nomenclature of Bacteria at the time of publication in the International Journal of Systematic Bacteriology, but are not to be considered to be included on the Approved Lists of Bacterial Names. Opinion 95

“…enzymogenes Christensen and Cook 1978, the combination Lysobacter enzymogenes subsp. cookii Christensen 1978 (Christensen & Cook, 1978) and the combination Streptococcus casseliflavus (Mundt & Graham, 1968) Vaughan et al 1979(Mundt & Graham, 1968Vaughan et al, 1979) were in accordance with the wording of the 1975 and 1992 revisions of the International Code of Nomenclature of Bacteria (Lapage et al, 1975(Lapage et al, , 1992 and that according to Rule 24a, Note 1 from the 1975 revision:…”

“…enzymogenes Christensen and Cook 1978, the combination Lysobacter enzymogenes subsp. cookii Christensen 1978 and the combination Streptococcus casseliflavus (Mundt & Graham, 1968) Vaughan et al 1979 were not included on the Approved Lists of Bacterial Names (Skerman et al, 1980(Skerman et al, , 1989, are not to be added and are, therefore, not validly published.…”

“…enzymogenes Christensen and Cook 1978, the combination Lysobacter enzymogenes subsp. cookii Christensen 1978 and the combination Streptococcus casseliflavus (Mundt and Graham 1968) Vaughan et al 1979 were in accordance with the wording of the 1975 and 1992 revisions of the International Code of Nomenclature of Bacteria but they are not to be considered to be included on the Approved Lists of Bacterial Names. Tindall & Euzéby (2006) presented evidence that the combination Lysobacter enzymogenes subsp.…”