Background: Campylobacter jejuni can cause a spectrum of diseases in humans, ranging from enteritis and diarrhoea to severe inflammation, profuse bloody diarrhoea and chronic relapsing infection. Norepinephrine (NE) levels in the intestine increase under conditions of stress and trauma, and are thought to result in spill over of NE into the intestinal lumen. NE is known to stimulate the growth of a range of bacterial species, and to increase the pathogenicity of Escherichia coli. Aim: To determine the effects of NE on the pathogenic potential of C jejuni in a model system. Methods: C jejuni was grown in iron-replete and iron-limited media in the presence and absence of 100 mM NE. Several virulence-associated characteristics, including motility and cell invasion, were measured. Results: When C jejuni was grown in iron-limited media in the presence of NE, growth rate, motility and invasion of cultured epithelial cells were increased compared with cultures grown in the absence of NE. Bacteria exposed to NE during growth also caused greater subsequent disruption of cultured epithelial cell monolayers, inducing widespread breakdown of tight junctions. Conclusion: Exposure to NE causes an increase in the virulence-associated properties of Campylobacter. Stress and concomitant infection could therefore be contributory factors to the variable presentation of this disease.

This study investigated the relationship between flock health and Campylobacter infection of housed commercial broilers in Great Britain. Thirty ceca were collected at slaughter from batches of broilers from 789 flocks, at either full or partial depopulation, between December 2003 and March 2006 and examined individually for Campylobacter by direct plating onto selective media. Management and health data were collected from each flock and included information on mortality or culling during rearing, the number of birds rejected for infectious or noninfectious causes at slaughter, the proportion of birds with digital dermatitis (also termed hock burn), and other general characteristics of the flock. Campylobacter spp. were isolated from 280 (35%) flocks. The relationship between bird health and welfare and Campylobacter status of flocks was assessed using random-effects logistic regression models, adjusting for region, month, year, and rearing regime. Campylobacter-positive batches of ceca were associated with higher levels of rejection due to infection (odds ratio [OR], 1.5; 95% confidence interval [CI 95% ], 0.98 to 2.30) and digital dermatitis (OR, 2.08; CI 95% , 1.20 to 3.61). Furthermore, higher levels of these conditions were also associated with the highest-level category of withinflock Campylobacter prevalence (70 to 100%). These results could indicate that improving health and welfare may also reduce Campylobacter in broilers.Campylobacter spp. are one of the most common bacterial causes of human enteritis in industrialized countries, according to the World Health Organization (http://www.who .int/mediacentre/factsheets/fs255/en/index.html). Chicken meat is frequently contaminated with Campylobacter (12, 26) and is a major source of human infection (1, 13). Reducing the number of contaminated carcasses would result in a reduction of food poisoning incidents. One way of achieving this would be to reduce the number of flocks carrying this pathogen, preslaughter (2).Campylobacter is generally regarded as a commensal in broiler chickens (21), but it may be possible to exclude it from housed flocks by the use of effective biosecurity, as studies in northern Europe and the United Kingdom have shown (2). However, this can be difficult to sustain in the long term (2), although monitoring may create incentives and promote consistent application of biosecurity. Other interventions may be necessary to support biosecurity (14), and one approach could be to improve our understanding of factors affecting the resistance of the birds to Campylobacter colonization. There is usually a commensal relationship between Campylobacter and chickens, but the bacteria have been associated with vibrionic hepatitis in these animals (28, 31). Preliminary work by the Bristol Group compared two farms in one company over six flock cycles. The farm with a high prevalence of Campylobacter-positive birds (97%) had higher levels of digital dermatitis and rejections at slaughter than the one where only 1.4% of birds were Campylobacter positiv...