Enterotoxigenicity and genetic relatedness of XXXX isolates from retail foods in the United States.

@entity6766 @entity1859 @entity1507 @entity3168 @entity28925 @entity68
@entity3168 is a leading cause of @entity6766 in countries where consumption of meat and poultry is high. For example, each year in the United States, this organism is the second or third most common cause of confirmed cases of @entity6766 . Surveys of the incidence of this organism in retail foods were done in the 1960s without regard to whether isolates were enterotoxigenic. It is now known that not all strains of this organism possess the @entity28925 gene responsible for illness. We examined the incidence of this organism in 131 food samples from retail food stores in an area of the northeastern United States. Forty isolates were obtained by using the @entity68 milk method at 45 degrees C, with confirmation by use of motility @entity1507 and lactose gelatin media. The presence of the @entity3168 @entity28925 (cpe) and alpha toxin (cpa) genes was determined by PCR using previously published primer sequences. All isolates possessed cpa. None of the isolates were identified as carrying the cpe gene by this method or by another method using a @entity1859 -labeled gene probe. Consistent with these results, none of the sporulating-cell extracts contained @entity28925 as determined by reverse passive latex hemagglutination. Pulsed-field gel electrophoresis was used to determine the genetic relatedness of the isolates. About 5% of the isolates were considered to be closely related (2- to 3-band difference). The others were considered to be unrelated to one another. The results demonstrate the rarity of cpe(+) strains in retail foods and the genetic diversity among nonoutbreak strains.
