In the present study, 103 Staphylococcus aureus strains isolated from milk samples from 60 cows with mastitis from eight different farms in seven different locations in one region of Germany were compared pheno-and genotypically and by identification of various toxins. On the basis of culture and hemolytic properties and by determination of the tube coagulase reaction, all of the isolates could be identified as S. aureus. This could be confirmed by PCR amplification of species-specific parts of the gene encoding the 23S rRNA. In addition, all of the S. aureus isolates harbored the genes encoding staphylococcal coagulase and clumping factor and the genes encoding the X region and the immunoglobulin G binding region of protein A. These four genes displayed size polymorphisms. By PCR amplification, the genes for the toxins staphylococcal enterotoxin A (SEA), SEC, SED, SEG, SEI, SEJ, and TSST-1 but not those for SEB, SEE, SEH, and the exfoliative toxins ETA and ETB could be detected. To analyze the epidemiological relationships, the isolates were subjected to DNA fingerprinting by macrorestriction analysis of their chromosomal DNAs. According to the observed gene polymorphisms, the toxin patterns, and the information given by macrorestriction analysis of the isolates by pulsedfield gel electrophoresis, a limited number of clones seemed to be responsible for the cases of bovine mastitis on the various farms.

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The present study was designed to investigate the significance and the relationship between nasal carriage of Staphylococcus aureus and staphylococcal skin infections. Thirty-one S. aureus strains, isolated from 12 patients with chronic and recurrent skin infections, one patient with septicemia and one patient with otitis externa were studied. The staphylococcal strains were isolated from the site of infection and from the anterior nares of each patient. The identity of both strains of each pair could be demonstrated by determination of phenotypic properties and by genotyping of the isolates. The phenotypic properties included hemolytic activities, antibiotic resistance data, and the production of enterotoxins. The identity was additionally confirmed by phage-typing, by determination of the size and the number of repeats of the X region of spa gene, by determination of gene polymorphisms of coa gene and by macrorestriction analysis of the chromosomal DNA of the isolates by pulsed-field gel electrophoresis. The present results showed an identity of the S. aureus obtained from anterior nares and from skin infection of each patient indicating the importance of nasal carriage of these bacteria for development of human skin infection.

The goal of the study was to genotypically compare S. aureus isolates from mastitis milk and raw milk to identify the
relation between strains and to assess the enterotoxigenicity of the isolates. Eighty-three Staphylococcus aureus isolates
recovered from cows and bulk tank milk of five farms in northern Italy were compared genotypically. The genes for the
enterotoxins A, D, G and I, but not for B, C, E and H and the toxic shock syndrome toxin 1 (TSST-1), were detected by
PCR amplification. Macrorestriction analysis with the restrictions enzyme SmaI revealed 14 pulsed-field gel electrophoresis
patterns. These were in part different from each other only in a few fragments and thus displayed a close
clonal relation. The results of the present investigation showed that identical or closely related clones seemed to be
responsible for the cases of bovine mastitis in the farms investigated and partly responsible for contamination of bulk
tank milk