Uberis Strains Research Articles

Evaluation of the Minitek Gram-Positive Set for identification of streptococci isolated from bovine mammary glands.

A total of 127 isolates were used to evaluate the Minitek Gram-Positive Set for identification of streptococci cultured from bovine mammary glands. The overall accuracy of the Minitek Gram-Positive Set was 34.6%. Of 12 Streptococcus agalactiae strains, 4 (33.3%) were correctly identified. Of 43 Streptococcus dysgalactiae strains, 32 (74.4%) were identified correctly. Of 44 Streptococcus uberis strains, 42 (95.5%) were identified as Enterococcus spp. Poor performance was attributed to the limited number of veterinary strains in the data base. Incorporation of large numbers of veterinary isolates into the data base is needed for further development of this system.

Evaluation of the Rapid Mastitis Test for identification of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands.

A latex agglutination test system (Rapid Mastitis Test [RMT]; Immucell, Portland, Maine) containing reagents for the identification of Staphylococcus aureus and Streptococcus agalactiae from bovine intramammary infections was evaluated with 527 staphylococcal and 267 streptococcal isolates. The RMT Staphylococcus aureus reagent detected 94.2% of 242 Staphylococcus aureus isolates, 80% of 25 Staphylococcus intermedius isolates, and 42.8% of 21 tube coagulase-positive Staphylococcus hyicus isolates. All Streptococcus agalactiae isolates were correctly identified by the RMT Streptococcus agalactiae reagent. Cross-reactions were observed with one Streptococcus dysgalactiae and three Streptococcus uberis strains. The RMT was found to be an acceptable method for the detection of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands. The occurrence of coagulase-positive staphylococci other than Staphylococcus aureus requires biochemical testing for species level identification.

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.