TAXONOMIC CHARACTERIZATION OF COAGULASE-NEGATIVE STAPHYLOCOCCI IN RIPENING FLORA FROM TRADITIONAL FRENCH CHEESES

Various methods were used to identify 145 staphylococcal strains isola ted from 25 traditional types of cheeses. With the biochemical microme thod rapid gallery system. ATE 32 Staph, only 33% of the strains could be identified. All the strains unidentified by API system (98 strains ) were subjected to 35 conventional biochemical and physiological test s according to the Devriese's identification scheme (1985). The result s were then analyzed by a numerical method using the Sokal and Michene r similarity coefficient and the 98 strains were distributed into 15 c lusters at the similarity level of 60%. Of the 145 strains analyzed, 3 6% were identified using the association of two phenotypic methods and 26% were considered as atypical S. xylosus or S. equorum strains. An identification method based on analysis of the ribotypes was applied t o 67 strains from the 15 taxa. The cellular DNA was cleaved by the Hin dIII and EcoRI restriction enzymes. The restriction fragments were sep arated by electrophoresis, blotted and probed with fluorescein labeled plasmid pBA2 containing a Bacillus subtilis gene encoding 16S rRNA. S ixty six of the 67 strains ribotyped (98.5%) gave typical known specie s patterns. In conclusion, 99.5% of the 145 staphylococcal cheese stra ins were identified. All chese strains belonged to the novobiocin-resi stant CNS species and near 90% to S. equorum, S. vitulus and S. xylosu s which are not widespread among human associated strains.