Case-control studyindependent cross-checkabstract checked★ key study I-CHK-128 in-depth review
Most Campylobacter infections in Germany trace back to chicken
A combined case-control and molecular source attribution study of human Campylobacter infections in Germany, 2011-2014.
Overview
Rosner BM et al.. Sci Rep 2017 · PMID 28698561 · DOI 10.1038/s41598-017-05227-x
About three quarters of human C. jejuni isolates were attributed to chickens; kitchen handling of raw poultry was a risk factor.
Does the study support the specific claim? Yes · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
What are risk factors for sporadic Campylobacter infection in Germany, and which animal sources contribute?
- How was the study done?
Case-control study plus MLST-based source attribution (asymmetric island model)
- How many people, animals or samples were studied?
not stated in abstract
- What was actually found?
Consumption of chicken meat and eating out were the most important risk factors; others: preparing poultry at home, preparing raw meat and uncooked food at the same time, contact with poultry, gastric acid inhibitors. Mean probability that human C. jejuni isolates originated from chickens 74%; C. coli 56% chicken and 32% pigs.
- How large was the observed effect?
Consumption of chicken meat and eating out were the most important risk factors; others: preparing poultry at home, preparing raw meat and uncooked food at the same time, contact with poultry, gastric acid inhibitors. Mean probability that human C. jejuni isolates originated from chickens 74%; C. coli 56% chicken and 32% pigs.
- What do the results mean in everyday life?
Chicken is the main source of this common food poisoning; kitchen hygiene matters.
- What are the study's limitations?
Attribution models assign reservoirs, not exposure route; Sample size not in abstract
- What does it say about Elawady's specific claim?
Directly supports the claim.
- Do the results apply to Germany and Europe?
German/EU data.
- What can explicitly not be concluded from this study?
Does not show that cooked chicken is unsafe.
Scientific in-depth review
1. Full reference
- Authors
- Rosner BM et al.
- Journal
- Sci Rep
- Year
- 2017
- Identifier
- PMID 28698561 DOI 10.1038/s41598-017-05227-x
- Verification
- verified – PubMed efetch 2026-10-26; Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Authors declare no competing interests
2. Research question
What are risk factors for sporadic Campylobacter infection in Germany, and which animal sources contribute?
3. Study design and population
- Study design
- Case-control study – Case-control study plus MLST-based source attribution (asymmetric island model)
- Population
Notified cases and controls; human and animal/food isolates
- Country
Germany
- Period
Nov 2011-Feb 2014
- Sample size
not stated in abstract
- Inclusion and exclusion criteria
as described in the abstract
4. Methods and endpoints
- Exposure / intervention
Chicken consumption, eating out, food preparation, animal contact
- Comparator
Controls; other animal sources
- Endpoints
Risk factors; attributable source probability
- Statistical methods
as reported in the abstract
5. Actual results
- Results
Consumption of chicken meat and eating out were the most important risk factors; others: preparing poultry at home, preparing raw meat and uncooked food at the same time, contact with poultry, gastric acid inhibitors. Mean probability that human C. jejuni isolates originated from chickens 74%; C. coli 56% chicken and 32% pigs.
- Absolute risks
not reported
- Authors' conclusion
Efforts are needed along the food chain to reduce Campylobacter load, especially on chicken meat.
6. Strengths
- Combines epidemiology and genotyping
- Large national study
7. Weaknesses
- Attribution models assign reservoirs, not exposure route
- Sample size not in abstract
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Case-control recall bias possible.
9. Assessment of the statistical interpretation
Two independent methods point to chicken as the main reservoir.
10. Relevance to the specific claim
Quantifies chicken as the main source of human campylobacteriosis in an EU country.
11. Independent contrary findings
12. Transferability to Germany and Europe
13. Overall methodological judgement
About three quarters of human C. jejuni isolates were attributed to chickens; kitchen handling of raw poultry was a risk factor.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- Chicken carries Campylobacter and Salmonella, which cause human infections. – Studies supporting the claim