Cells of the pathogenic

In the gut, many pathogens adhere to the gut wall and produce their toxic effect via toxins which pervade the surrounding gut wall or enter the systemic circulation. Vibrio cholerae and some enteropathic E. coli strains localize on the gut wall and produce toxins which increase vascular permeability. The end result is a hypersecretion of isotonic fluids into the gut lumen, acute diarrhoea and consequent dehydration which may be fatal in juveniles and the elderly. In all these instances, binding to epithelial cells is not essential but increases permeation ofthe toxin and prolongs the presence of the pathogen. 

However, in case of acute clinical mastitis, it is widely accepted that animal welfare considerations should take prevalence. If both farmer and veterinarian are not familiar with non-antibiotic treatments, they should be advised to use broad-spectrum antibiotics immediately, because any delay (e.g. the 2-3 days it often takes between diagnosis and the return of microbiological test results) may seriously harm the animal. This approach should, however, only be taken after a sound clinical diagnosis, since antibiotic treatments themselves may lead to dramatic aggravation of the condition. For example, E. coli inflammations are able to develop into severe toxaemia, because increased levels of toxins are released into the animal tissues when E. coli cells are killed or stressed by antibiotic treatments. Also, if yeasts are the main cause or form part of the pathogen complex that causes mastitis, their growth and proliferation may be supported by the administration of anti-bacterial antibiotics (Crawshaw et al., 2005). 

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