Persistence of Salmonella Senftenberg in poultry production environments and investigation of its resistance to desiccation
Résumé
Most Salmonella serovars, including Salmonella enterica subsp. enterica serovar Senftenberg (S. Senftenberg), are tolerant to desiccation and able to colonise and persist in feed mills. In addition, they may survive cleaning and disinfection procedures used on poultry farms. This study was conducted to investigate the survival of S. Senftenberg in broiler parent stock (PS) farms and broiler farms. The isolates from one of the parent stock farms investigated only differed by a single band in fluorescent amplified fragment length polymorphism analysis (AFLP) and had identical pulsed field gel electrophoresis (PFGE) profiles, indicating that a S. Senftenberg clone had persisted for more than two years, despite cleaning, disinfection, desiccation and depopulation, and was subsequently able to infect Salmonella free layers. Isolates from the same house on a different broiler PS farm were found to be identical by AFLP and PFGE although the farm tested negative for Salmonella 55 times over a period of 18 months between the two positive samplings. An assay was developed to investigate the survival of 34 S. Senftenberg isolates during desiccation at approximately 38% relative humidity. On average, the viability of S. Senftenberg isolates decreased by 1000 fold over 35 days. The persistent clones were not any more resistant to desiccation than the other isolates investigated. However, S. Senftenberg was more resistant to desiccation than an isolate of Pantoea agglomerans commonly found on poultry feed processing lines. This study demonstrates the risk of persistence of feed-associated serovars such as S. Senftenberg.
Origine : Fichiers produits par l'(les) auteur(s)