Cross-sectional studyindependent cross-checkfull text checked I-CHK-09 in-depth review
Salmonella in Egyptian broiler chickens
Antimicrobial resistance profiles and virulence genotyping of Salmonella enterica serovars recovered from broiler chickens and chicken carcasses in Egypt.
Overview
Elkenany R et al.. BMC Vet Res 2019 · PMID 31029108 · DOI 10.1186/s12917-019-1867-z
About 29% of retail chicken carcasses and 32% of farm chickens in one Egyptian province had Salmonella, mostly multidrug-resistant.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Prevalence, resistance and virulence genes of Salmonella in broilers and retail carcasses
- How was the study done?
Cross-sectional microbiological survey
- How many people, animals or samples were studied?
420 samples from 5 broiler farms and 5 retail shops, El-Sharkia, summer 2017
- What was actually found?
Salmonella in 28.6% of all samples (carcasses 29.4%, cloacal swabs 32%, environment 22%); 76.7% of isolates multidrug-resistant; all resistant to trimethoprim-sulfamethoxazole; none to imipenem.
- How large was the observed effect?
Descriptive
- What do the results mean in everyday life?
In Egypt, careful handling and cooking of chicken is especially important.
- What are the study's limitations?
Only 5 farms and 5 shops in one province, one season; no human data; descriptive only.
- What does it say about Elawady's specific claim?
Supports concern but not 80-85%.
- Do the results apply to Germany and Europe?
Low (Egypt).
- What can explicitly not be concluded from this study?
Not national.
Scientific in-depth review
1. Full reference
- Authors
- Elkenany R et al.
- Journal
- BMC Vet Res
- Year
- 2019
- Identifier
- PMID 31029108 DOI 10.1186/s12917-019-1867-z
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
No funding; authors declare no competing interests.
2. Research question
Prevalence, resistance and virulence genes of Salmonella in broilers and retail carcasses
3. Study design and population
- Study design
- Cross-sectional study – Cross-sectional microbiological survey
- Population
Five small-scale broiler farms (birds at 3 weeks of the growing cycle; farm environment incl. water, feed, litter, fans, workers' hands) and five retail shops (freshly dressed whole carcasses, outer skin)
- Country
Egypt (El-Sharkia)
- Period
Summer 2017
- Sample size
420 samples: 150 cloacal swabs (30 per farm), 100 environmental samples (20 per farm), 170 carcasses (34 per shop); 120 Salmonella isolates
- Inclusion and exclusion criteria
Samples described as randomly collected from 5 farms and 5 retail shops in El-Sharkia Province; selection of farms/shops not described.
4. Methods and endpoints
- Exposure / intervention
Not applicable
- Comparator
Not applicable
- Endpoints
Prevalence; resistance; virulence genes
- Statistical methods
Descriptive frequencies; ISO-type culture, serotyping (White-Kauffmann-Le Minor), CLSI disc diffusion for 11 antimicrobials, PCR for 10 virulence genes; MDR = resistance to >=3 classes; MAR index.
5. Actual results
- Results
Salmonella in 120/420 samples (28.6%): cloacal swabs 32% (48/150), environment 22% (22/100), retail carcasses 29.4% (50/170). Serotypes: S. Enteritidis 11.4%, S. Typhimurium 8.6%, S. Kentucky and S. Molade 2.85% each, others <1.5%. Resistance: trimethoprim-sulfamethoxazole 100%, ampicillin and amoxicillin-clavulanate 68.3% each, streptomycin 65%, doxycycline 40%, cefaclor 36.7%, chloramphenicol 16.7%, cefotaxime and cefepime 13.3% each, ciprofloxacin 10%, imipenem 0%. MDR in 92/120 (76.7%), MAR index 0.2-0.6. invA in 100%, csgD 90%, hilC 60%; sopE1 and pefA absent.
- Absolute risks
not applicable (contamination survey; no human data)
- Authors' conclusion
Biosecurity and biocontrol measures needed.
6. Strengths
- Farm-to-retail sampling in an Egyptian setting directly relevant to the archive's region
- Serotyping, CLSI susceptibility testing and virulence-gene PCR
7. Weaknesses
- Only 5 farms and 5 shops in one province, single summer season; small clusters (34 carcasses per shop) not accounted for
- Selection of farms and shops not described
- Disc diffusion only; no molecular resistance mechanisms
- Several reported counts are suspiciously uniform (e.g. virulence profiles in exact multiples of 12), suggesting rounding or reporting issues
- No human exposure or illness data
8. Risk of bias
- Orienting tool
- none (microbiological prevalence survey; no standard RoB tool applies)
- Type of assessment
- structured assessment based on the full text by a single reviewer (no formal double review)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Unchanged (some_concerns), bordering high for representativeness. Single-reviewer structured judgement; a formal assessment would need two independent reviewers.
| Domain | Judgement | Rationale |
|---|---|---|
| Sampling/selection | high | 5 farms and 5 shops, selection unexplained, one province, one season. |
| Laboratory measurement | some concerns | Standard culture/serotyping and CLSI disc diffusion, but no QC or confirmatory MIC testing reported. |
| Analysis | some concerns | No clustering adjustment or CIs. |
| Reporting | some concerns | Some implausibly uniform counts; minor inconsistencies. |
Full-text review (25 October 2026): Added sampling frame (5 farms, 5 shops, summer 2017), sample-type prevalences (carcasses 29.4%), full resistance profile, no funding; noted reporting oddities. Bias unchanged.
9. Assessment of the statistical interpretation
Descriptive prevalence without CIs or clustering adjustment; the carcass prevalence (29.4%) is a local estimate, not national.
10. Relevance to the specific claim
C-CHK-08, C-CHK-05, C-CHK-09 (Egypt).
11. Independent contrary findings
Not applicable.
12. Transferability to Germany and Europe
Low (Egypt).
13. Overall methodological judgement
Small local Egyptian survey showing that about 29% of retail carcasses and 32% of broilers in El-Sharkia carried Salmonella, mostly multidrug-resistant; supports the existence of a resistant-pathogen hazard in Egyptian poultry but contradicts an 80-85% contamination figure.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | low |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
National, representative Egyptian prevalence and resistance surveillance; human attribution.
15. Linked fact checks
- Industrial chicken is raised with routine antibiotics, and antibiotic-resistant bacteria (e.g., ESBL E. coli, MRSA, resistant Campylobacter, mcr-1) spread from poultry to humans via the food chain. – Studies supporting the claim
- About 80-85% of chickens are contaminated with Salmonella, even with the cleanest slaughter methods (the blood is contaminated). – Studies contradicting or limiting the claim
- Chicken carries Campylobacter and Salmonella, which cause human infections. – Studies supporting the claim