Molecular Investigation of Enterotoxigenic Staphylococcus aureus Isolates from Restaurant Staff

Abstract

Background: Intoxication by heat-resistant Staphylococcus aureus enterotoxins (SEs), particularly SEA and SEE, is one of the most common causes of food poisoning in the world. Objectives: This study aimed to identify enterotoxin-encoding genes (see, sed, sec, seb, sea) in S. aureus isolates from different restaurant employees. Methods: Ninety-one samples from the hands and noses of employees of several restaurants in the Golestan Province (North of Iran) were examined for detection of S. aureus strains by the phenotypic and microbiological genotyping methods. After determining the susceptibility of the isolates to ten antibiotics by the Kirby-Bauer method, the enterotoxin-producing genes were detected using the polymerase chain reaction method. Results: S. aureus was detected in 29 (31.9%) samples. The frequency of S. aureus isolates was highest in waiters (65.5%) with the age range of 34-49 years (41.4%) and nasal samples (55.1%). The highest and lowest susceptibility rates were observed against linezolid (100%) and cefoxitin (17.24%). Of 19 methicillin-resistant S. aureus strains, 89.47% were identified as multi-drug resistant and 10.52% as extensively-drug resistant. Of 29 S. aureus isolates, 24.13% were enterotoxigenic, with the highest frequency belonging to SEA (57.1%). Conclusions: In this study, we isolated multi-drug resistant, enterotoxigenic S. aureus from different restaurant employees, which can have important public health implications. Therefore, it is recommended to closely monitor the health, sanitation, and hygiene of people involved in food preparation to reduce the spread of bacteria in the food chain.