Diversity of Salmonella serovars in feedyard and nonfeedyard playas of the Southern High Plains in the summer and winter

Objective-To compare Salmonella isolates cultured from feedyard and nonfeedyard (control) playas (ie, temporary shallow lakes) of the Southern High Plains. Sample Population-Water and muck (sediment) samples were obtained from 7 feedyard playas and 3 nonfeedyard playas in the winter and summer. Procedure-Each water and muck sample was enriched with sulfur-brilliant-green broth and incubated in a shaker at 37degreesC for 24 hours. A sample (100 mL) of the incubated bacterial-enriched broth was then mixed with 100 mL of fresh sulfur-brilliant-green enrichment broth and incubated in a shaker at 37degreesC for 24 hours. After the second incubation, a swab sample was streaked on differential media. Suspect Salmonella isolates were further identified by use of biochemical tests, and Salmonella isolates were confirmed and serovar determinations made. Results-Salmonella isolates were not recovered from the 3 control playas. Seven Salmonella enterica serovars were isolated from 5 of 7 feedyard playas in the summer, and 13 S enterica serovars were isolated from 7 of 7 feedyard playas in the winter. In the summer, 296 isolates were cultured, and 47 were Salmonella organisms. In the winter, 288 isolates were cultured, and 171 were Salmonella organisms. Conclusions and Clinical Relevance-Results indicated that feedyard playas are frequently contaminated with many Salmonella serovars. These pathogens should be considered whenever feedyard managers contemplate the use of water from these playas. Water from feedyard playas should not be used to cool cattle in the summer or for dust abatement.