Genome sequence of stable Campylobacter strain deciphered

19/09/07 Scientists of the Institute of Food Research and their collaborators at the veterinary pharmaceutical company Intervet have deciphered and published the complete genome sequence of a strain of Campylobacter jejuni. The food-poisoning bacterium C. jejuni is one of the major causes of gastroenteritis in humans, causing diarrhoea, stomach cramps and in rare cases a nervous condition called Guillain-Barré syndrome. Humans are commonly infected by eating undercooked poultry meat, which is contaminated during processing of the chickens. Surprisingly, the Campylobacter bacterium is commonly carried in the gut of birds without causing disease in the birds.

Like many bacteria, C. jejuni is able to avoid our body’s defences by altering the nature and content of its surface. These alterations are achieved by having regions of the bacterial chromosome that are able to make small random variations, resulting in different surface structures.

Genomic variability has been a problem for researchers investigating C. jejuni, since it potentially also causes differences between laboratories and even between experiments. In a project funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and Intervet, the Campylobacter group at IFR has determined and analysed the complete genome sequence of Campylobacter jejuni strain 81116 (also known as NCTC11828). This strain was selected because of its previously reported genomic stability over time.

The genome sequence reported by IFR and Intervet is 1,628,114 bases in length and notable for having fewer of the variable regions than the previously reported C. jejuni sequences. Strain 81116 is widely studied as it is amenable to genetic alterations, and grows well in poultry allowing this important natural reservoir to be studied. Thus the reported sequence will provide useful information for Campylobacter researchers worldwide, and is predicted to be a valuable resource for the research community.

Campylobacter research at IFR focuses on understanding the molecular processes involved in Campylobacter infections. State-of-the art techniques are used or developed for the analysis of virulence gene regulation and bacterial responses to stresses encountered during infection of avian and mammalian hosts or during survival in the environment. The aim is to provide an integrated, holistic approach to the investigation of Campylobacter biology and pathogenesis of infection, by combining both the study of Campylobacter physiology and genetics.