B10004: Assessment relative to other pathways of the contribution made by the food chain to the problem of quinolone resistance in microorganisms causing human infections
Monday 8 March 2004
This research project will assess the contribution of the food chain to the problem of quinolone resistance in micro-organisms causing human infection relative to other pathways.
Background
Campylobacter is the most common cause of foodborne illness in the UK and since the introduction of quinolones in human and veterinary medicine Campylobacter, in both humans and animals has been quick to develop resistance to this antimicrobial. The role of the food chain (in particular the use of quinolones as a therapeutic in food animal production) in the emergence of quinolone-resistant Campylobacter in humans is uncertain. The aim of this project is to assess, relative to other pathways, the contribution made by the food chain to quinolone infection in humans, using a quantitative risk assessment approach.
Research Approach
A number of identified risk pathways were investigated. These were:
- Food: chicken (conventional, free-range, organic, non-UK), pigs, vegetable crops;
- Environment, public water supplies, pets (dogs and cats);
- Human: foreign travel, human use of ciprofloxacin for the treatment of Campylobacter.
A number of other potential exposure pathways were considered but a quantitative risk model could not be developed due to lack of suitable data. These were: turkey, halal chicken, private water supplies, rendering, recreational water activities, wildlife, visits to pasture, and farm/abattoir workers.
Results and findings
It was concluded that the majority of quinolone resistant Campylobacter (QRC) cases in the UK (59.6%) are attributable to QRC exposure while abroad.
It was estimated that chicken consumption was the source of 8% of cases of which 1.3% and 6.7% were attributed to domestic and non-UK chicken respectively. Contact with pets (dogs and cats) was the source in 3.63% of cases, whilst clinical treatment of quinolone-susceptible Campylobacter accounted for less than 1.5% of total cases.
In total, pig meat consumption, public water consumption and crop consumption on average contributed less than one QRC case per year. It was concluded that these sources are not significant for human QRC cases.
Approximately 70.7% of total cases are estimated to be attributable to these quantified pathways. Therefore 30% of total cases are the result of other sources than those considered here.
Campylobacter is the most common cause of foodborne illness in the UK and since the introduction of quinolones in human and veterinary medicine Campylobacter, in both humans and animals has been quick to develop resistance to this antimicrobial. The role of the food chain (in particular the use of quinolones as a therapeutic in food animal production) in the emergence of quinolone-resistant Campylobacter in humans is uncertain. The aim of this project is to assess, relative to other pathways, the contribution made by the food chain to quinolone infection in humans, using a quantitative risk assessment approach.
A number of identified risk pathways were investigated. These were:
- Food: chicken (conventional, free-range, organic, non-UK), pigs, vegetable crops;
- Environment, public water supplies, pets (dogs and cats);
- Human: foreign travel, human use of ciprofloxacin for the treatment of Campylobacter.
A number of other potential exposure pathways were considered but a quantitative risk model could not be developed due to lack of suitable data. These were: turkey, halal chicken, private water supplies, rendering, recreational water activities, wildlife, visits to pasture, and farm/abattoir workers.
It was concluded that the majority of quinolone resistant Campylobacter (QRC) cases in the UK (59.6%) are attributable to QRC exposure while abroad.
It was estimated that chicken consumption was the source of 8% of cases of which 1.3% and 6.7% were attributed to domestic and non-UK chicken respectively. Contact with pets (dogs and cats) was the source in 3.63% of cases, whilst clinical treatment of quinolone-susceptible Campylobacter accounted for less than 1.5% of total cases.
In total, pig meat consumption, public water consumption and crop consumption on average contributed less than one QRC case per year. It was concluded that these sources are not significant for human QRC cases.
Approximately 70.7% of total cases are estimated to be attributable to these quantified pathways. Therefore 30% of total cases are the result of other sources than those considered here.
The project investigated the banning of the use of quinolones in UK broiler production. Under this scenario, it was predicted no QRC cases would be attributed to UK chicken. Hence there would be a 1.3% decrease (mean) in the total number of human cases. Diverting flocks treated with a fluorequinolone to frozen chicken production would reduce the number of QRC cases by 1,139.
The debate on whether to cease the use of fluorequinolones is still ongoing, but it is important to note that in food-animal production fluorequinolones are prescribed for therapeutic purposes. This risk assessment has only investigated the consequence of fluorequinolone use in broiler flocks. There are many more issues that would also need to be considered to inform a risk management decision.
An alternative control strategy would be to reduce carcass contamination levels of Campylobacter by approximately 1 log at the end of processing. This was estimated to have a 100 fold reduction in the number of Campylobacter. Hence, control measures for Campylobacter are also an effective way of reducing the number of human QRC in addition to reducing the total number of Campylobacter spp. cases in humans.
Interpretation of all the model results must be done with care because many data gaps/deficiencies were identified during the development of the risk assessment.
Dissemination information
*Project completed - Final report is awaited.
*Project completed - Final report is currently being evaluated by the Agency.
*The final report is available from the Agency’s Information Centre.
To obtain a copy, please contact the Enquiry Desk, Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email: infocentre@foodstandards.gsi.gov.uk)
For any enquiries concerning this research project, please contact the relevant Programme contact or email: science@foodstandards.gsi.gov.uk