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.

Fourteen (20.9%) of 67 horses with a positive bacterial culture from synovial fluid were subjected to euthanasia because of persistent synovial sepsis compared to 2 (1.44%) of 139 with negative bacterial cultures (P<0.001). Overall survival and successful long-term return to function in horses with a positive bacterial culture was 50% (24/48 horses) compared to 70.5% (74/105) in culture negative horses (P=0.01). In horses that survived to be discharged, successful long-term return to function was not significantly different between culture positive and culture negative groups. Growth of Staphylococcus aureus from synovial fluid did not affect short-term survival to discharge from the hospital compared to other positive bacterial culture; however, successful long-term return to function was only 30.4% (4/13) in horses from which S. aureus was cultured compared to 73.9% (17/23) of horses in which other bacteria were cultured (P=0.015). CONCLUSIONS AND POTENTIAL CLINICAL RELEVANCE: Horses with a positive bacterial culture from a septic synovitis have a poorer prognosis for survival to discharge from hospital and overall long-term return to function than horses that yielded no bacterial growth. When S. aureus was cultured, the long-term prognosis was poorer.

Nonsteroidal anti-inflammatory drug choice did not affect major clinical outcomes in horses with SSI lesions but had some effects on signs of pain. This study provides no evidence to recommend one NSAID treatment above another based on survival or the incidence of ileus; however, evaluation of a larger number of cases is required.

Summary.A restriction fragment length polymorphism (RFLP) typing method for Legionella pneumophila serogroup 1 was developed. The method depended upon the use of cloned EcoRl fragments from L. pneumophila (Knoxville-1) probing Neil restriction fragments of chromosomal DNA. Examination of strains of L. pneumophila which were apparently unrelated showed that inter-strain RFLPs were common, and these formed the basis of the typing scheme. The technique was found to be highly reproducible and discriminatory. When the RFLP data were compared to that obtained by monoclonal antibody (MAb) subgrouping both methods of strain differentiation gave consistent results. The isolates examined by either method were also sub-divided by the alternative technique. The analysis of RFLPs by cloned probes should be of considerable epidemiological value.

The enzyme linked immunosorbent assay (ELISA) described was developed to detect a soluble antigen in the urine of