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The Most Common Cause Of Food Poisoning In The UK: Campylobacter jejuni
Campylobacter jejuni is a Gram-negative, spiral bacterium which causes food poisoning (gastroenteritis) when food contaminated with it is consumed. Being microaerophilic and thermophilic, it grows best in environments with little oxygen and temperatures of around 42°C: perfect for growth in the intestines of warm-blooded organisms, particularly birds. It is a motile organism as it possesses long polar flagella at either end of it (lophotricious), enabling it to propel itself around the body in fluids and spread disease.
When sampled on “CAMP” agar plates in the laboratory,Campylobacter colonies will appear almostround, with smooth edges.They can grow thick and white or thin and transparent - depending on the strain and the incubating conditions.
Campylobacter is the most common cause of food-borne gastroenteritis in the UK, with reported cases now twice that of Salmonella food-poisoning. Due to the increasing number of cases, it is growing more resistant to antibiotic treatments, and this could be a problem in the future.
What disease does it cause?
C. jejuni causes Campylobacteriosis, often known as a form of gastroenteritis.Diarrhoea (which can often be watery and containing blood and white cells) is the most common and prominent manifestation of infection. Other symptoms can include:
- Abdominal and general musclepain
- Nausea and headaches
Symptoms will usually appear within 1-2 days of being affected, and can last up to 10. Complications of this illness are rare, but it can cause Guillan-Barré syndrome (can result in paralysis) in extreme cases, after several weeks of acute illness.
Method of transmission
This bacterium can enter humans by ingesting contaminated food (chicken, meat or dairy products) or water. This may be by eating the food directly, or coming into contact with unwashed equipment/not washing your hands after handling meat.
Infection process and mechanisms of disease
This bacterium essentially infects and establishes itself inside an organism by the following sequence of events: cell invasion, toxin production, inflammatory response and finally the resulting diarrhoeal disease.
Firstly, the C. jejuni will interact with the gut epithelial cells after being ingested. They pass through the protective mucus layer and cause interleukin 8 (IL-8) production. The bacterium will bind and enter into the intestinal cells while the secreted interleukins will recruit macrophages and neutrophils. This results in aninflammatory response, increasing the number of cytokines in the area, and finally resulting in the contraction of a diarrhoeal disease by the individual.
How to avoid infection
As this microorganism spreads easily and has a very low infective dose, some simple steps must be taken to reduce the risk of infection:
- Cook all meat products (particularly chicken) thoroughly, to a high temperature
- Wash hands with soap after handling raw animal products - good personal hygiene
- Keeping kitchen utensils and surfaces clean, and using separate utensils for separate ingredient types, e.g. separate meat and vegetables
- Avoid using unpasteurised milk and untreated water
- Avoid touching/preparing food if you are ill or have cuts on your hands
- Do not reheat food more than once
- Keep certain foods refrigerated to prevent bacterial growth
The Food Standards Agency recommends remembering the fours C’s: cleaning, cooking, chilling and cross-contamination—all of which are covered in the simple rules above!
As with any type of food-poisoning, patients with a C. jejuni infection should drink plenty of fluids to rehydrate and replenish water stores lost through diarrhoea, get plenty of rest, and try to eat only easily digestible foods so that the gut can be rested as much as possible.
It is usually a self-limiting disease, but antibiotics may be given to shorten the illness or in very bad cases. Around 90% of cases will respond well to ciprofloxacin, but erythromycin is often prescribed too, and works well too. Specific treatment of the condition will depend on the severity, and a doctor should always be contacted before any medication is taken.
However, as with many pathogens,Campylobacter jejuni is rapidly growing resistance to many of the commonly used drugs - this will call for new drugs to be found in the future, and is a frustrating problem that scientists now face with a range of diseases worldwide!