Multiplex PCR strategy for the simultaneous identification of Staphylococcus aureus and detection of staphylococcal enterotoxins in isolates from food poisoning outbreaks

Abstract

Introduction: Staphylococcal food poisoning is the most frequent type of food poisoning around the world. Staphylococcus aureus enterotoxins cause significant loss of water in the intestinal lumen, followed by vomiting and diarrhea.

Objective: To report a fast, reliable and inexpensive strategy based on multiplex PCR for the simultaneous identification of S. aureus and detection of five classical S. aureus enterotoxin genes (sea, seb, sec, sed, see) in Staphylococcus spp. strains isolated from food poisoning outbreaks.

Materials and methods: We analyzed isolates from 12 food poisoning outbreaks occurred in Santa Fe province (Argentina). Isolation and phenotypic characterization were carried out by standard procedures. Genotypic analysis was performed by multiplex PCR, using primers for nuc, sea-see and 16S rRNA genes simultaneously.

Results: Of all the strains tested, 58% were found to carry toxigenic genes. Sea and seb toxins were found at the same percentage (29%) while sec, sed and see genes were found in a lower and identical proportion (14%). We did not find more than one different type of S. aureus enterotoxin in the isolates analyzed.

Conclusions: The multiplex PCR strategy designed in this work has enabled us to identify strains of S. aureus and detect -at the same time- their enterotoxigenic ability. At present, our efforts are devoted to the detection of genes encoding enterotoxins other than the classical ones, in order to know their impact on staphylococcal food poisoning, as well as to investigate their relevance to our country’s public health.

http://dx.doi.org/10.7705/biomedica.v33i1.816