Shigellaas a Foodborne Pathogen and Current Methods for Detection in Food

Abstract

Shigella, the causative agent of shigellosis or "bacillary dysentery," has been increasingly involved in foodborne outbreaks. According to the Centers for Disease Control and Prevention's Emerging Infections Program, Foodborne Diseases Active Surveillance Network (FoodNet), Shigella was the third most reported foodborne bacterial pathogen in 2002. Foods are most commonly contaminated with Shigella by an infected food handler who practices poor personal hygiene. Shigella is acid resistant, salt tolerant, and can survive at infective levels in many types of foods such as fruits and vegetables, low pH foods, prepared foods, and foods held in modified atmosphere or vacuum packaging. Survival is often increased when food is held at refrigerated temperatures. Detection methods for Shigella include conventional culture methods, immunological methods, and molecular microbiological methods. Conventional culture of Shigella in foods is often problematic due to the lack of appropriate selective media. Immunological methods for Shigella have been researched, yet there is only one commercially available test kit. Molecular microbiological methods such as PCR, oligonucleotide microarrays, and rep-PCR have also been developed for the detection and identification of Shigella. This manuscript reviews the general characteristics, prevalence, growth and survival, and methods for detection of Shigella in food.

A food-borne outbreak of Shigella sonnei gastroenteritis, Austria, 2008

“…One of the striking features of foodborne outbreaks caused by shigella is that in many situations contamination of foods may not have originated pre-harvest in the field (e.g. from fecally contaminated irrigation water) or post-harvest at the processing plant but rather the source can be traced to symptomatic or asymptomatic food handlers [27]. The spread of the pathogen may occur via fingers, flies, or inanimate objects such as utensils and cutting surfaces.…”

Faecal Contaminants in Edible Bivalves from Maputo Bay, Mozambique: Seasonal Distribution, Pathogenesis and Antibiotic Resistance

“…Among the other isolated coliformic Enterobacteriaceae, Shigella sp. was identified even though we did not use any selective methodology [32] to trace it. This observation is of great concern since Shigella even in low doses can cause severe gastrointestinal infection through seafood consumption [33] and it points out the need for further investigations.…”

Isolation & Identification of Shigella species from food and water samples of Quetta, Pakistan

“…Several researchers have concluded that several outbreaks of shigellosis were associated with the consumption of fresh products that are prepared by hand and are served uncooked or raw [22][23][24]. In addition, previous research data indicated that consumption of unhygienic food is the most common contributing factor in shigellosis in underdeveloped and developed nations [25][26][27]. The detection of Shigella species from ready-to-eat salad revealed the inadequate safety and quality of these products.…”