RTD info MAYO 2005 - Surt

32RTD info No. 45 May 2005HEALTH RISKSCampylobacteria are the primarycause of a vast range of foodinfections worldwide. Yet weknow surprisingly little aboutthem and the tools for isolating,cultivating and describing them areinadequate. A consortium of European,South African and American scientists recently undertook topursue research into this unjustifiably neglected microbialfamily and to evaluate its potentially infectious impact.Helicobacter pyloriis the new name forCampylobacter pylori, whosepathogenic role in certainforms of gastritis andduodenal ulcers wasrecently identified.Campylobacteriaunder the microscope© A. Labigne/Institut PasteurAround 4 000 species of bacteria have been identified to date, butnobody knows how many really inhabit the Earth. Yet a betterknowledge of the biodiversity of the bacterial world has implicationsthat extend far beyond fundamental microbiology, as it could helpus identify the culprits behind infectious diseases, particularly those offood origin.Given that the causes of the vast majority of sometimes seriousfood infections remain unknown, the Campycheck project is of majorimportance. It aims to study the biodiversity of campylobacteria, agroup of bacteria that are presumed responsible for around 600 millioninfections worldwide every year. This is applied research in the field offood safety.Campylobacteria are bacteria in the shape of curved rods. Theyinhabit the digestive tract of animals – on farms and in the wild – andprefer oxygen-poor environments, some of them tolerating strictlyanaerobic conditions. They are pathogenic in man, affecting mainlychildren and young adults and causing severe diarrhoea which, in turn,can lead to complications such as intestinal haemorrhage or generalisedinfection. In some – fortunately rare – cases, they develop into aserious neurological syndrome: in Guillain-Barré disease, the antibodiesthe organism secretes to combat the infection subsequently attackneurons, leading to general paralysis.Contamination can be either from direct contact with animal excrement,polluted water, or – most commonly – consumption of contaminatedfoods such as chicken, pork or mutton which have been cleanedinadequately in abattoirs, and also unwashed vegetables, unpasteurisedmilk, etc.Two culprits?Although we are aware of about 30 campylobacteria varieties,research to date has focused almost exclusively on just two of them:Campylobacteria jejuni and Campylobacteria coli. This is because C. jejuniand C. coli have traditionally been identified as the ‘presumed culprits’of 99% of infections attributable to this microbial family. “All present proceduresare designed to investigate these two targets that are able to surviveat temperatures of 42°C,” explains William Keevil of SouthamptonUniversity (UK), the Campycheck coordinator. “Standardised and effectivemethods for detecting them are now available, thanks in particularto the Campynet programme, a network of 23 European laboratories supportedby the European Union between 1998 and 2001.”