Evaluation of persistence and distribution of Salmonella serotype isolation from poultry farms using drag-swab sampling.

The consistency and persistence of isolation of specific serotypes of Salmonella were evaluated on a 31-farm broiler complex following four complete sampling periods. A total of 25 different serotypes were isolated, with multiple serotypes and were frequently isolated simultaneously from individual farms. When the serotypes recovered from individual farms were further examined, common serotypes were isolated from individual farms on only seven occasions. Furthermore, on only five occasions were multiple serotypes recovered from individual farms on consecutive samplings. A casual association of common serotype isolations among farms with similar flock placement dates was observed in one sampling period. These results indicate little predictability or consistency of Salmonella serotype isolation on individual farms over time.