Genotyping by PCR, of Staphylococcus aureus strains, isolated from mammary glands of cows.

A total of 71 Staphylococcus aureus strains isolated from bovine mammary glands were identified and subtyped. The methods used to differentiate between the S. aureus isolates were the DNA polymorphism pattern after amplification with a Polymerase Chain Reaction using several primer combinations and phage typing. The DNA fingerprinting technique using RAPD, ERIC1R and ERIC primers proved to be useful in differentiating isolates of S. aureus. Differentiation of isolates using phage typing gave no additional information compared to the DNA technique. The outbreak of S. aureus in the herd studied was mainly caused by one S. aureus strain. Other strains were only found on three occasions, twice in subclinical infections and once from a case of clinical mastitis. In the latter case the dominant strain was isolated from a different quarter of the same cow. Four of the ten cows studied suffered from clinical mastitis. From those four cows, three remained infected with the same S. aureus strain despite antibiotic treatment.

[Staphylococcus aureus in poultry slaughter lines]. / Staphylococcus aureus in pluimveeslachtlijnen.

The skins of slaughtered poultry were studied for the presence of Staphylococcus aureus in eight poultry-processing plants. Bacteriophage typing showed that S. aureus persisted as 'house bacteria' in all slaughter lines under investigation. As a result of this fact, broilers became contaminated with S. aureus during the process of slaughter. The number of S. aureus organisms finding their way to the carcasses may vary from less than 10/g. of skin to greater than 50,000/g. of skin from one day to another when samples are taken. This finding is evidence of the fact that disinfection occurs at irregular intervals. However, the persistence of particular phage types in processing plants also suggests that the apparatus employed cannot be effectively cleansed and disinfected by a simple procedure.

Investigation by pyrolysis mass spectrometry, phage pattern and plasmid analysis of staphylococci that have reverted from 'L'-phase to bacterial phase.

No major differences have been found in series of Staphylococcus aureus strains which reverted from 'L'-phase, either by pyrolysis mass spectrometry or by phage-typing or sensitivity testing. In 'L'-phase they have been subcultured for a long time or transformed/reverted many times into/from 'L'-phase. Plasmids were lost during transformations/reversions, but there was some difference between the tetracycline-connected plasmids on the one hand and the erythromycin-connected ones on the other.

A second site-specific restriction endonuclease from Staphylococcus aureus.

A site-specific restriction endonuclease has been isolated from Staphylococcus aureus PS 96. This enzyme, Sau96 I, recognizes the DNA sequence 5'--G-G-N-C-C--3' and cleaves as indicated by the arrows. The enzyme 3'--C-C-N-G-G--5' cleaves adenovirus type 5 and lambda DNA many times, SV40 DNA 10 times and 0X174 RF DNA 2 times. Evidence is presented that the enzyme is involved in biological restriction-modification.

Transferability of macrolide, lincomycin, and streptogramin resistances between group A, B, and D streptococci, Streptococcus pneumoniae, and Staphylococcus aureus.

The transferability of plasmid pRI405 between various streptococci of groups A, B, and D, Streptococcus pneumoniae, and Staphylococcus aureus is described. pRI405 originated from Streptococcus faecalis and encodes for resistance to macrolides, lincomycin, and streptogramin B (MLS resistance). The host range of the well-documented streptococcal plasmid pAM beta 1 was found to be similar to that of pRI405. Cleavage with restriction enzymes suggests that pRI405 belongs to a related family of MLS resistance plasmids.