Streptococcus uberis: an Approach to its Classification

Thirty-one strains of streptococci, selected because they were considered to be or were similar to Streptococcus uberis , were examined by physiological tests and for properties of their lactate dehydrogenases (LDHs) and deoxyribonucleic acid (DNA). Twenty-nine of the 31 strains fell into two main genotypes as judged by DNA/DNA hybridization. One genotype (Group I) included the type strain of Strep. uberis and most other strains in this group were physiologically similar to it and had the same percent guanine + cytosine (%GC) in their DNA. The other genotype (Group II) contained strains which were more variable physiologically and had DNA of a lower % GC than the type strain. The European strains examined contained two distinct LDH types, one being associated with the Group I and the other with Group II strains. Three American strains examined however had LDH's which were unlike those of the European strains.