Cross-sectional studyindependent cross-checkfull text checked I-EGG-126 standard review
Salmonella found inside some Egyptian market eggs
Antimicrobial Resistance of Salmonella enteritidis and Salmonella typhimurium Isolated from Laying Hens, Table Eggs, and Humans with Respect to Antimicrobial Activity of Biosynthesized Silver Nanoparticles.
Overview
Abou Elez RMM et al.. Animals (Basel) 2021 · PMID 34944331 · DOI 10.3390/ani11123554
3.6% of retail table egg contents in Sharkia carried Salmonella, often drug-resistant.
Does the study support the specific claim? Unclear · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Measure Salmonella in hens, eggs and people in Egypt.
- How was the study done?
Cross-sectional sampling.
- How many people, animals or samples were studied?
431 samples incl. 165 eggs.
- What was actually found?
Salmonella present in eggs and hens; high resistance.
- How large was the observed effect?
Egg contents 3.6%.
- What do the results mean in everyday life?
In Egypt, eggs should be cooked well, especially for vulnerable people.
- What are the study's limitations?
Small regional sample.
- What does it say about Elawady's specific claim?
Does not test cages vs cage-free.
- Do the results apply to Germany and Europe?
Low.
- What can explicitly not be concluded from this study?
It cannot compare housing systems.
Scientific in-depth review
1. Full reference
- Authors
- Abou Elez RMM et al.
- Journal
- Animals (Basel)
- Year
- 2021
- Identifier
- PMID 34944331 DOI 10.3390/ani11123554
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
No specific funding; no conflicts declared (full text).
2. Research question
How prevalent and resistant are S. Enteritidis and S. Typhimurium in laying hens, table eggs and humans in Sharkia, Egypt?
3. Study design and population
- Study design
- Cross-sectional study – Cross-sectional prevalence and resistance study
- Population
Laying hen faecal swabs, retail table eggs and human stool samples, Sharkia Governorate
- Country
Egypt
- Period
August 2019-January 2020
- Sample size
431 samples (166 faecal swabs, 165 table eggs, 100 stool samples)
- Inclusion and exclusion criteria
not detailed in abstract
4. Methods and endpoints
- Exposure / intervention
Not applicable
- Comparator
Not applicable
- Endpoints
Salmonella isolation, serotypes, resistance, virulence genes
- Statistical methods
Descriptive
5. Actual results
- Results
Salmonella in 19.3% of all samples; laying hens 33.1%; Salmonella in egg contents 3.6%; S. Enteritidis 5.8% and S. Typhimurium 2.8% overall; multidrug resistance 83.8% of isolates.
- Absolute risks
not reported
- Authors' conclusion
Isolates from hens, eggs and humans showed resistance to multiple antimicrobial classes.
6. Strengths
- Egyptian retail eggs
- One Health sampling
7. Weaknesses
- Single governorate
- Housing system not compared
- Main focus on nanoparticles
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Convenience sampling.
9. Assessment of the statistical interpretation
Descriptive prevalence only.
10. Relevance to the specific claim
Shows Salmonella occurs in Egyptian retail eggs (contents 3.6%), which supports cooking eggs thoroughly; it does not address housing systems.
11. Independent contrary findings
EU eggs 0.31% positive (I-EGG-14).
12. Transferability to Germany and Europe
Egypt-specific.
13. Overall methodological judgement
Relevant to safety advice in Egypt, not to the cage comparison.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | unknown |
| Consistency with the overall evidence | unknown |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
National Egyptian monitoring data.
15. Linked fact checks
- Salmonella is far more common in caged egg production than in cage-free systems (44% vs 3.2%). – Studies with mixed or unclear results