RT Journal Article SR Electronic(1) A1 Roop, Dennis R. A1 Mundt, J.Orvin. A1 Riggsby, W. Stuart.YR 1974 T1 Deoxyribonucleic Acid Hybridization Studies Among Some Strains of Group D and Group N Streptococci JF International Journal of Systematic and Evolutionary Microbiology, VO 24 IS 3 SP 330 OP 337 DO https://doi.org/10.1099/00207713-24-3-330 PB Microbiology Society, SN 1466-5034, AB The degree of homology between group D (Streptococcus faecalis and S. faecium) and group N(S. lactis)streptococci was assessed by deoxyribonucleic acid (DNA)-DNA hybridization. Interspecific DNA duplexes between S. faecalis and S. faecium exhibited high levels (>75%) of formation at 60 and 70 C, and low levels (<10%) of DNA duplex formation were observed between group D and group N organisms at 60 and 70 C. Thermal stability studies indicated less than 2% unpaired bases in these duplexes. Atypical strains which have characteristics of both group D and group N streptococci were included in an attempt to identify them with established species. The results indicate that DNA-DNA hybridization studies may be useful in placing atypical strains in a particular species if screening of physiologic properties is used to separate these strains into groups resembling S. faecalis, S. faecium and S. lactis. Results obtained with an authentic strain of S. faecium subsp. casseliflavus Mundt and Graham indicate that this organism deserves the subspecific designation., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-24-3-330