B03014: Whole genome analysis fluorescent AFLP: identification of post-specificity genes of campylobacter and their values as epidemiological markers
Wednesday 25 June 2003
This research project developed a tool for identifying strains of campylobacter, this was used to help understand the sources of campylobacter food poisoning and how it is spread.
Background
In order to understand the sources of campylobacter food poisoning and how it is spread, we need good epidemiological tools. We have therefore funded the development of the fingerprinting technique fluorescent amplified fragment length polymorphism (fAFLP) and applied it to campylobacter as an identification method.
Research Approach
The method of fluorescent amplified fragment length polymorphism (fAFLP) was used to fingerprint campylobacter strains from poultry, cattle, pigs, humans and meat on retail sale, to look for evidence of host-specificity or host-association.
Results and findings
In order to determine the source of human campylobacter infections, it would be advantageous if you could tell which source it originated from, for example, a chicken or a pig or a cow or meat on retail sale. One way to investigate this is to perform DNA profiling on campylobacter isolates from potential food sources, where you get a barcode of different sizes of DNA bands for each isolate. By comparing these profiles, you can look to see there are any bands common to only chicken strains. If you could find such a band, it could then serve as a marker for infection arising from consuming or handling chicken, when examining human isolates. This in turn could help to prevent the spread of campylobacter to humans in the future.
There are two major species of campylobacter which are responsible for the majority of human infections, namely, C. coli and C. jejuni. This study investigated a collection of C. jejuni and C. coli strains from chickens, cattle, pigs, humans and meat on retail sale, to look for evidence of these host markers.
The study investigated a collection of 276 strains of C. jejuni and 87 C. coli strains from chickens, cattle, pigs, humans and meat on retail sale.
The research identified 13 markers which informed that the species was C. coli, and 2 markers for the species C. jejuni. Within the C. coli collection, pig and chicken strains were separated by their DNA profiles and five potential host markers for this were found. Further testing is required to prove this conclusively. In contrast, the C. jejuni collection showed no direct evidence of host markers, which means that it is not possible using this DNA profiling method to determine the source of human infection.
The work has identified particular Campylobacter “finger prints” which are associated with particular animal hosts. The findings support the view that fAFLP is a very precise, accurate and valid genotyping system and this work has made it available for the first time for Campylobacter. It is a useful tool for epidemiological studies and for tracing campylobacters through the food chain.
Dissemination information
Final report is available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency (020 7276 8181/8182 or at library&info@foodstandards.gsi.gov.uk).
Publications and Presentations:
Hopkins K. L., Logan J. M. J., Desai M., Frost J. A., Stanley J. 200X. A comparison of FAFLP genotyping and sero/phage typing of Campylobacter jejuni and Campylobacter coli from humans and animals. [In preparation].
Hopkins K. L., Logan J. M. J., Desai M., Frost J. A., Stanley J. 200X. Host-specificity and host-association of Campylobacter jejuni and Campylobacter coli strains: a study using FAFLP. [In preparation].
Desai, M., J. M. Logan, J. A. Frost, and J. Stanley. 2001. Genome sequence-based fluorescent amplified fragment length polymorphism of Campylobacter jejuni, its relationship to serotyping, and its implications for epidemiological analysis. J. Clin. Microbiol. 39:3823-3829.
Logan J. M. J., Hopkins K. L., Desai M., Frost J. A., Stanley J. 2001. FAFLP genotyping of Campylobacter jejuni and Campylobacter coli from humans and animals. PHLS 26th Annual Scientific Conference, 17-19 September, University of Warwick, UK, Session 11 PHLS/VLA initiative in foodborne zoonoses - Oral presentation.
Hopkins K. L., Logan J. M. J., Desai M., Frost J. A., Stanley J. 2001 FAFLP genotyping of Campylobacter jejuni and Campylobacter coli from humans and animals. 11th International Workshop on Campylobacter, Helicobacter and related organisms. September 1-5, Freiburg, Germany, Poster Abstract H21.
Contact: Kathryn Callaghan
Tel: 020 7276 8943
Email: micro.research@ foodstandards.gsi.gov.uk