Campylobacter jejuni is a gram negative bacterium, which is long, thin, spiral, with one flagella at either end, making it highly motile. It is thermophilic, and microaerophilic (prefers less than 10% O2 and more than 5% CO2). This bacterium lives in the avian caecum in an environment of around 42oC. The bacteria usually live within poultry, but when it is transferred to humans and mammals, usually through undercooked meat, it can cause diarrhoea, and food poisoning (gastroenteritis).
The number of reported cases of Campylobacter infections has been significantly increasing since the 90’s, this has occurred along side the decline of the more publicly known Salmonella infections. The reasons why Campylobacter is increasing could be because we just do not know enough about this bacterium, such as how it is spread, how we become infected, and its general biology.
So what do we know? Campylobacter is a zoonotic pathogen, which is found by DEFRA in 2004 to be in 63% of chicken meat, 55% of cattle, 44% of sheep, and 69% of pigs present at slaughter. In 2000 the food standards agency in England, found 1.3 million cases, yet this figure only represents diagnosed cases, the actual figure is probably much higher.
Campylobacter causes disease through a 2-5 day incubation period, where the infected person may have abdominal pain, fever, diarrhoea. Campylobacter jejuni gets its name from the mucosal damage it causes to the ileum and jejunum. Campylobacter infections are mainly caused by two bacteria, C. jejuni, and C. Coli, although C. jejuni occurs up to 80% less than C. coli. These bacteria cause damage to the intestine through invasion and the production of toxins such as CDT. It colonises the mucus, and adheres to cells through using its flagella, and binding factors.
As well as causing an initial symptom of gastroenteritis, Campylobacter has been associated with Guillian Barre syndrome (1 case per 1000), an autoimmune disease of the peripheral nerves, causing acute paralysis. Which occurs because LOS structures (lipooligosaccharide) on the bacteria are detected by the hosts antibodies, however these LOS structures have a very similar structure to the gangliosides found in neurons, it is believed that in Guillian Barre syndrome, our antibodies attack the nervous system, mistaking it for the bacterium.
It is important that further research into Campylobacter occurs, it is an important bacteria which costs a lot of aggravation, as any one who has ever had food poisoning will know, and it can also cause a deaths, and high health care costs in the cases of Guillina Barre syndrome. We need to develop better methods to prevent the spread of this bacteria within our food industry.