Incidence of Salmonella serovars isolated from commercial animal feed mills in the United States and serovar identification using CRISPR analysis

Aims In this study, we sought to determine the incidence and diversity of Salmonella in a broad collection of commercial animal feeds collected from animal feed mills across the United States over an 11-month period and utilize CRISPR analysis to identify individual serovars. Methods and Results Over two independent trials, 387 feed samples from 135 different animal feed mills in the United States were screened for Salmonella. A total of 6 center dot 2% (24/387) of samples were contaminated with Salmonella, which is concordant with similar studies. Clustered regularly interspaced short palindromic repeats (CRISPR)-typing was used to serotype Salmonella isolates, and serovars Infantis and Tennessee were the most common. Conclusions Serogroups O:4 and O:7 were enriched in the feed samples, suggesting that these serogroups are better adapted to surviving in low moisture animal feeds. The study supports the utility of CRISPR to determine serovar type since most of the serovars identified in this study have been also isolated and identified in earlier studies using more classical serotyping methods. Significance and Impact of the Study This work contributes to a growing body of literature concerning the Salmonella prevalence in animal feeds and highlights the need to effectively mitigate pathogens in livestock and poultry feed.

Automated summary

The study aimed to investigate the incidence and diversity of Salmonella in commercial animal feeds in the US and identified Infantis and Tennessee as the most common serovars. Serogroups O:4 and O:7 were found to be enriched in the feed samples, indicating their better adaptation to low moisture animal feeds. The use of CRISPR analysis was shown to be effective in determining serovar type.