Toxigenic status of XXXX isolated from @entity291 raw milk and Minas frescal cheese in Brazil.

@entity1793 @entity291 @entity794
A group of 291 @entity794 isolates from mastitic @entity291 's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for @entity1793 ( @entity1793 ) genes (sea, seb, sec, sed, see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the @entity794 isolates bearing @entity1793 genes, 17 (13.6%) were from mastitic @entity291 's milk, 41 (41.7%) were from bulk tank milk, and 51 (72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described @entity1793 genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical @entity1793 genes (sea through see, 15 strains). The @entity1793 genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic @entity291 's milk. Macrorestriction analysis of chromosomal DNA from 89 @entity794 isolates positive for @entity1793 gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, Apa I, used for some isolates was less discriminating than Sma I. The high genotype diversity of potential toxigenic @entity794 strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety.
