[Dichotomous keys for identifying Staphylococcus isolated from bovine milk].

Many efforts have been done in order to identify species of Gram positive and catalase positive coccus isolated from raw milk. The aim of this epidemiological observation, was to identify different strains isolated from raw milk according to conventional criteria and to recommend a useful and practical methodology for their correct identification. Gram positive and catalase positive coccus were tested for bacitracin resistance, novobiocin susceptibility, coagulase and others tests (e.g. carbohydrate fermentation). Dichotomic keys were designed to typify Staphylococcus' species. They were grouped into: Group I, coagulase positive, novobiocin susceptibility; Group II coagulase negative novobyocin resistance; and Group III coagulase negative novobiocin susceptibility. 62 strains were tested and S. hycus (17.7%) was the most isolated species, S. aureus (14.5%), S. sciuri (12.9%) and S. haemolyticus (11.3%) were also isolated. S. epidermidis was not isolated.