LGC supports food industry with new test for Campylobacter
17 Sep 2010
Novel molecular DNA identification approach from LGC offers potential for improved foodborne bacteria diagnosis
Research at LGC, the UK’s designated National Measurement Institute for chemical and bioanalytical measurement, has demonstrated proof of principle for a novel molecular DNA diagnostic technique to identify specific species of Campylobacter; a bacterium related to foodborne illnesses.
Of the five major foodborne bacteria; Salmonella, Campylobacter, E.coli 0157, Listeria monocytogenes and Clostridium perfringens, Campylobacter is the most common cause of foodborne illness in the UK. In 2008, there were 49,880 cases of Campylobacter infection in England and Wales, compared with 9,867 of Salmonella*. Virtually all cases of Campylobacter infection occur as isolated, sporadic events, not as a part of large outbreaks.
The traditional method of identifying bacterial pathogens associated with foodborne illnesses is examination via pour plate technology with biochemical reactions and identification and enumeration by microscopy. However, this approach could be criticised as being time-consuming and somewhat subjective.
LGC’s research focuses on a more accurate and efficient approach for species identification; LGC scientists have modified routine polymerase chain reaction (PCR) methods to differentiate successfully two of the most common Campylobacter species; C. coli and C. jejuni, by their unique DNA profiles. Proof of principle for LGC’s technique was demonstrated using Campylobacter DNA supplied by ATCC via LGC Standards, the exclusive European distributor of ATCC biological cultures and bioproducts.
Through expertise in refining PCR and the optimisation of previously published methods, LGC’s scientists have reduced the time taken to carry out the amplification step in the PCR process by 50% and improved assay efficiency by decreasing both, reagent volumes by 75% and the use of primers and enzymes by 85%. The technique employs the novel use of a restriction enzyme which also enables significantly improved experimental repeatability.
The FSA’s strategic plan for 2010 - 2015 sets one of its main priorities as ensuring ‘Food produced or sold in the UK is safe to eat’ and cites the reduction of foodborne disease, specifically in tackling the incidences of Campylobacter in chicken as one of its main objectives. Foodborne illness can be caused by the consumption of food contaminated with bacteria and their toxins.
LGC’s molecular DNA technique demonstrates the potential to give very specific identification of different Campylobacter species based on unique DNA profiles. Whilst this approach is still in its early stages of development, the technique has demonstrated the potential to differentiate efficiently between species, and could, in future, contribute to the Food Standards Agency (FSA) initiative to manage the prevalence of Campylobacter in UK food sources.
* Source: HPA Centre for Infections. Provisional data.