缅北禁地

Abstract

Campylobacter jejuni and C. coli are the most significant cause of bacterial gastroenteritis in humans both in the UK and worldwide. As the most common host for Campylobacter spp., poultry are frequently infected and subsequent spread of the pathogen between rearing mates in a broiler chicken shed is rapid. Up to 100% prevalence in flocks is common, which translates into an estimated 70% attribution rate related to the handling and consumption of raw or undercooked chicken meat in the UK. Preliminary consultation with the poultry industry suggests that their most immediate need is determination of Campylobacter infection status of broiler flocks on-farm which, with a user friendly test, could be conducted by, for example, farm or area managers. At present, there are no rapid and sensitive in situ Campylobacter tests to allow stakeholders in the food supply chain to (i) determine levels of environmental contamination before an infection is established in a flock; (ii) determine flock prevalence just prior to processing; or (iii) determine contamination on chickens carcasses during or following processing or in the retail environment.

Description

Routine detection of Campylobacter typically involves a 48 hour cultivation by selective enrichment under specific growth conditions, followed by detection using selective agar plating (requiring a further 48 hours of incubation followed by confirmation testing). At present, there are no rapid and sensitive in situ Campylobacter tests available. The use of a lateral flow device (LFD) can significantly reduce the result time but LFDs do not have sufficient sensitivity to be used for environmental detection without preliminary (48 hour) enrichment. This is therefore not suitable as a rapid in situ test. Campylobacter can also be detected using PCR-based methods but requires that the sample undergoes extensive preparation to extract the DNA and remove the environmental contaminants that interfere with the PCR reactions. Further, should the amplicon (part of the DNA that is detected and is amplified as part of the process) escape into the environment, the area becomes contaminated, giving false positives with every sample taken. PCR or other DNA amplification processes are not readily incorporated into simple and inexpensive devices suitable for use in the challenging environments found throughout the food supply chain. Biosensors, on the other hand, offer a relatively simple technology platform that is robust, sensitive and specific. The development of a biosensor for Campylobacter jejuni and C. coli would offer the poultry industry an economical and portable means of rapidly detecting these pathogens in environmental samples on-farm.