Multiplex PCR and sandwich ELISA for identification of enterotoxigenic Staphylococcus aureus isolated from Egyptian soft cheese

Document Type : Original Articles

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Abstract

Staphylococcus aureus (S. aureus) has the ability to produce heat stable enterotoxins resulting in food intoxication in human with varying intensity. So, the present study was designed to identify and characterize coagulase positive S. aureus producing enterotoxins using multiplex polymerase chain reaction (PCR) as well as, detection of enterotoxins using ELISA in Egyptian soft cheese. One hundred samples represented as (40 Kareish cheese, 30 Damietta cheese, and 30 Feta cheese) were collected randomly from different supermarkets, and street-vendors at Alexandria city, Egypt for isolation of coagulase positive S. aureus. The obtained results revealed that coagulase positive S. aureus was isolated with a percent 7.5, 16.66 and 6.66% of examined samples of (Kareish, Damietta and Feta cheeses, respectively). Among the isolated strains, five strain were positive for the different serotypes (A, B, C and D) of staphylococcal enterotoxins (SE) genes using multiplex PCR. Direct Screening of samples for SE Using sandwich ELISA showed that SE type A was detected among the examined Kareish and Damietta cheese samples; enterotoxin C was detected only in Damietta cheese samples while enterotoxin D was detected only in Feta cheese. The generated data were showing that soft cheese produced in Alexandria city, Egypt poses a high risk to public health and also the overall quality of Egyptian soft cheese is still low. In conclusion, sandwich ELISA is a good approach for detection of staphylococcal enterotoxins in contaminated soft cheese produced in Alexandria city.

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