| Titre : | A Dual-Target Colorimetric LAMP Platform for Salmonella Surveillance in the Poultry Supply Chain: A One Health Approach |
| Auteurs : | SKENNDRI Safae, Auteur ; NASSIK Saâdia |
| Type de document : | texte imprimé |
| Editeur : | Rabat : IAV Hassan II, 2026 |
| Format : | 285 pages |
| Note générale : |
Formation Doctorale : Sciences vétérinaires
Unité de Recherche : Pathologie des maladies animales, épidémiologie et santé publique vétérinaire |
| Langues: | Anglais |
| Mots-clés: | Salmonella ; Colorimetric LAMP ; Point-of-Care ; Salmonella Gallinarum ; Salmonella Enteritidis ; Food Safety ; Poultry ; Extraction-Free ; One Health |
| Résumé : |
Foodborne pathogens, particularly Salmonella in poultry, represent a persistent and significant challenge at the intersection of animal health, public health, and economic stability, embodying a classic "One Health" problem. This challenge manifests as a dual threat: motile, zoonotic serovars like S. Enteritidis, which silently contaminate the food chain and pose a widespread public health risk; and non-motile, host-adapted pathovars like S. Gallinarum which cause fowl typhoid, a devastating disease with high flock mortality that is recognized as notifiable by the
World Organisation for Animal Health (WOAH). Effectively managing both of these distinct threats requires rapid surveillance and intervention at the source. However, conventional detection methods, such as bacteriological culture and laboratory-based PCR, are timeconsuming, costly, and infrastructure-dependent, severely limiting their utility for the on-site screening and immediate action required in both food safety and farm biosecurity contexts. This thesis describes the complete development, optimization, and validation of a dual-gene colorimetric Loop-Mediated Isothermal Amplification (LAMP) platform to address this detection gap. The system comprises two distinct assays: a genus-level test targeting the conserved invA and hilA genes for broad Salmonella spp. screening, and a novel discriminatory assay targeting a Taxon-Restricted eXclusive (TRX) sequence for the specific identification of the non-motile, avian-pathogenic S. Gallinarum and S. Pullorum (SPG) group. A custom, inhouse colorimetric buffer utilizing Phenol Red was formulated and optimized to enable a clear, equipment-free, red-to-yellow visual readout. The analytical performance of the optimized assays demonstrated high specificity and excellent sensitivity, with limits of detection ranging from approximately 4 to 10 CFU per reaction, roving comparable or superior to quantitative PCR. The platform's practical utility was then validated on complex biological matrices. On cloacal swabs from experimentally infected chickens, a rapid heat-shock protocol coupled with the LAMP assays significantly outperformed traditional bacteriology, increasing the detection rate of S. Gallinarum by up to 25%. For food safety applications, a novel NaOH-based pre-treatment protocol was successfully developed to neutralize the intrinsic acidity of poultry meat, enabling effective detection. This complete "sample-to-answer" workflow demonstrated a sensitivity of 1-10 CFU/µL on purified DNA from spiked meat, and a practical sensitivity of 10²-10³ CFU/µL with the rapid heat-shock method. 4 Collectively, this work delivers a validated, cost-effective, and field-deployable screening and detection platform. By providing a rapid and reliable tool that serves both animal health surveillance (via the SPG-TRX assay) and food safety screening (via the genus-level assays), this platform represents a significant advancement in point-of-care detection methods and offers a practical instrument for strengthening Salmonella control from farm to fork within a One Health framework |
| Examinateur : | Bengoumi, M/FELLAHI Siham |
| Président : | FASSI FIHRI Ouafaa |
| Rapporteur : | Sbai-Idrissi Karim/Fechatli Taoufiq |
| Directeur de thèse : | NASSIK Saâdia |
| Membre du comité : | LAHKAK Fatima Ezzahra/Abdellaoui Maane Imane |
| En ligne : | http://10.2.0.27/PDF_CDA/uploads/PDF/SKENNDRI_Safae_2026_216.pdf |
Exemplaires (1)
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| 200042108 | CED 216 | Support papier | Espace 1er étage | CEDoc | Consultation sur place Exclu du prêt |
