BACKGROUND: Staphylococcus aureus is one of the most important pathogenic bacteria for human that is easily transferred during slaughtering, processing, packaging, storage and handling of meat and meat products as a result of poor hygienic principles, and causes staphylococcal food poisoning. Objectives: The objective of this study was to evaluate the contamination of raw and cooked ground beef in retail shops of Mazandaran to S. aureus and also detection of enterotoxin-producing genes in the isolates. Methods: One-hundred fifty ground beef samples (95 raw and 65 cooked) were collected randomly from retail shops, 21 May-21 July 2017. S. aureus was counted via culturing on Baird Parker Agar medium. Detection of enterotoxins A-E and G, H, I and J producing genes was conducted applying real-time PCR technique. Results: 68% of samples showed S. aureus contamination. The average count in raw and cooked ground beef samples was 3.1×105 cfu/g and 5.7×103 cfu/g, respectively. From 92 S. aureus isolates, 23 isolates (25%) were carrying enterotoxin coding genes; amongst them 15 isolates (65.2%) were carrying just a single gene and the rest more than one gene. Two isolates carrying SEA+ SEC, two isolates SEA+SEE, one isolate SEA+SEG, one isolate SEC+SEI, one isolate SEA+SEC+SEG and one isolate SEE+SEG. Conclusions: These results show that enterotoxigenic S. aureus strains are present on considerable numbers in retail ground meat in Mazandaran.

The present investigation was undertaken to study the occurrence of enterotoxigenic B. cereus from 200 samples including 100 raw milk, 50pasteurized milk and 50 ice cream samples sold in Puducherry. The results revealed that 68 samples (34 %) belonged to B. cereus group which included 36 from raw milk (36%), 9 from pasteurized milk (18%) and 23 from ice cream samples (46 %). On PCR analysis, 64 out of 68 isolates showed the presence of gyrB gene which differentiates B. cereus from B. cereus group isolates. Multiplex PCR revealed the presence of four enterotoxigenic genes hblA, nheA, cytK and entF Min 32.35 %, 77.94 %>, 54.41 % and 94.12% of the 64 isolates. On biofilm production assay, out of 64 enterotoxigenic B. cereus isolates, 60 (93.75 %) isolates showed the ability to form biofilm in which 13 (20.31 %) were strong, 21 (32.81 %) were moderate and26 (40.63 %) were weak biofilm producers. All the isolates were resistant to ampicillin and penicillin G and sensitive to ciprofloxacin, gentamicin, vancomycin, streptomycin and norfloxacin. The current study directs the need for proper hygienic measures during collection, production, processing and storage of milk to reduce the contamination level. It also indicates the need for surveillance and action to reduce the contamination of enterotoxigenic B. cereus in milk and milk products in Puducherry.

This study was conducted to record the potential risk of some pathogens in table eggs in Beni-Suef city, Egypt. A total of 100 table eggs samples (Farm and Baladi eggs) were randomly collected from poultry farms, markets, supermarkets and groceries in Beni-Suef city, 50 farm eggs samples (each of 3 eggs) and 50 baladi eggs samples (each of 5 eggs) were examined for the presence of coliforms, E.coli, Salmonella, coagulase positive Staphylococcus aureus and Staphylococcal enterotoxins. Isolates were identified by biochemical, serological and molecular (PCR) methods. The obtained results in the present study revealed that (22%) of the examined samples were contaminated with Coliforms. The other identified genera were Citrobacter freundii, Citrobacter diversus, Edwardsiella tarda, Enterobacter spp., Morgonella morganii, Klebsiella oxytoca, Providencea spp., Serratia fonticola and Yersinia intermedia. E.coli (atypical type) was detected in a percentage of 27.27%. True fecal E. coli and Salmonella spp. failed to be detected in any of the whole examined 100 eggs samples. Additionally, Staphylococcus spp. was detected with incidence rate of (13%), out of them, 8 (61.5%) isolates were accounted for coagulase positive Staphylococcus aureus. Enterotoxin profiling revealed that two classical enterotoxin genes (SEA and SED) were detected either singly or in combination. The potential health hazards and the suggested control measures of the isolated strains had been discussed.

Three enterotoxigenic isolates of Staphylococcus aureus previously isolated from contaminated milk and evaluated for their enterotoxin producing ability and histopathological changes by the ligated rabbit ileal loop assay. The results of this assay revealed that crud toxin obtained by these isolates caused fluid accumulation in rabbit ileal loops. Fluid aspirated from the loops was bloody and the histopathological changes in sections were characterized by moderate to sever haemorrhage, erosion and inflammatory cells, in addition there was distortion and shift of villi. This finding established that staphylococcal enterotoxin that associated with vomiting and diarrhea , which often abate within 24 hrs., there was potential risk for more serious disturbances such as inflammation, tissue damage and toxic shock.