DETECTION, DISTRIBUTION AND PROBABLE FATE OF ESCHERICHIA-COLI O157 FROM ASYMPTOMATIC CATTLE ON A DAIRY FARM

The use of commercial anti-Escherichia coli O157-labelled magnetic bea ds was investigated to improve detection of E. coli O157 by immunomagn etic separation (IMS) from a range of environments on a dairy farm. Im munomagnetic separation proved effective for separation of target cell s from laboratory mixtures and during stress in sterile and non-steril e pond water. The IMS procedure was possible with a range of samples ( water, faeces, slurry, grass and soil). Non-specific binding of nontar get bacterial cells proved problematic in a number of sample types. Ho wever, indigenous E. coli O157 cells were detected from samples with a high faecal load, and only with use of IMS. Data on the probable surv ival and spread of the organism around the farm environment are also d iscussed.