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United States Department of Agriculture

Agricultural Research Service

Research Project: HANDLING AND TRANSPORT STRESS INTERACTIONS WITH PATHOGEN BIOLOGY IN SWINE AND CATTLE

Location: Livestock Behavior Research

Title: Comparison of five culture methods for Salmonella isolation from swine fecal samples of known infection status

Authors
item Love, B - OKLAHOMA STATE UNIVERSITY
item Rostagno, Marcos

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 20, 2008
Publication Date: N/A

Interpretive Summary: This study was conducted in order to evaluate five commonly used bacteriologic culture methods (Methods 1, 2, 3, 4, and 5) for recovery of Salmonella enterica from swine feces, both for sensitivity of detection (ability to recover Salmonella from a positive sample), and for specificity (not to inadvertently identify an organism as Salmonella species in a negative sample). Fifty six negative samples and forty six positive samples were processed using each of the five methods, which differed primarily in the combinations of enrichment media used. All negative samples were negative for Salmonella when cultured by all five methods (100% specificity). Two of the methods (Methods 1 and 4) resulted in the recovery of significantly less Salmonella when compared to the remaining three methods (Methods 2, 3, and 5). No one method was successful in recovering Salmonella from all positive samples, although recovery with Method 2 was statistically similar to the total number of positive samples analyzed (42 versus 46 Salmonella-positive samples). This study shows that culture methods differ significantly in their performance regarding the isolation of Salmonella from swine fecal samples. This side-by-side evaluation of culture methods for sensitivity and specificity will facilitate the standardization of methods, enabling comparison of results obtained in different laboratories and countries.

Technical Abstract: This study was conducted in order to evaluate five commonly used bacteriologic culture methods (Methods 1, 2, 3, 4, and 5) for recovery of Salmonella enterica from swine feces, both for sensitivity of detection (ability to recover Salmonella from a positive sample), and for specificity (not to inadvertently identify an organism as Salmonella species in a negative sample). Fifty six negative samples and forty six positive samples were processed using each of the five methods, which differed primarily in the combinations of enrichment media used. All negative samples were negative for Salmonella when cultured by all five methods (100% specificity). Two of the methods (Methods 1 and 4) resulted in the recovery of significantly less (P<0.05) Salmonella when compared to the remaining three methods (Methods 2, 3, and 5). No one method was successful in recovering Salmonella from all positive samples, although recovery with Method 2 was statistically similar to the total number of positive samples analyzed (42 versus 46 Salmonella-positive samples, P>0.05). This study shows that culture methods differ significantly in their performance regarding the isolation of Salmonella from swine fecal samples. This side-by-side evaluation of culture methods for sensitivity and specificity will facilitate the standardization of methods, enabling comparison of results obtained in different laboratories and countries.

Last Modified: 7/28/2014
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