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Abstract

Objective—To compare 3 alternative culture techniques for the detection of Salmonella organisms in swine feces with a modification of the International Standard Organization (ISO) 6579 standard protocol.

Sample Population—Fecal samples from swine herds suspected of having Salmonella infections.

Procedure—4 experiments were performed to evaluate the following: 1) diagnostic sensitivity of the selective preenrichment and rapid isolation novel technology (SPRINT) protocol, compared with that of the modified ISO protocol; 2) detection limit of the SPRINT protocol for Salmonella organisms; 3) use of tetrathionate-novobiocin (TTN) broth, compared with selenite cysteine (SC) broth for selective enrichment; and 4) use of universal preenrichment (UPE) broth, compared with buffered peptone water (BPW) for preenrichment of samples prior to the use of modified semisolid Rappaport-Vassiliadis (MSRV) plates.

Results—Comparing the Salmonella culture results of 183 swine fecal samples, the diagnostic sensitivity of the SPRINT protocol (0.86) was not significantly different than the diagnostic sensitivity of the modified ISO protocol (0.80), although it was 24 hours faster. The SPRINT protocol could detect 5 of the 6 investigated Salmonella serotypes at inoculation concentrations of < 10 colony-forming units (CFU)/25 g of uncontaminated feces. The TTN broth performed significantly better than the SC broth for selective enrichment of Salmonella organisms. There was no significant difference in results of preenrichment of samples between the use of UPE broth or BPW.

Conclusions and Clinical Relevance—The SPRINT protocol may provide a faster alternative for isolation of Salmonella organisms from swine fecal samples. Furthermore, the use of TTN broth instead of SC broth may increase the sensitivity of the modified ISO 6579 protocol. (Am J Vet Res 2000;61:1426–1429)

Full access
in American Journal of Veterinary Research

SUMMARY

We investigated the ability of an antibody-specific, O antigen-based elisa to document Salmonella typhimurium herd infections by screening of milk samples. Three cattle populations, 20 herds with no history of salmonellosis, 8 herds with history of S typhimurium epsiodes within the previous 7 months, and 220 herds of unknown disease status, were tested. A herd was considered elisa positive if at least 5% of the cows had OD values > 0.3. Among the 20 herds without history of salmonellosis, only 2 herds were elisa positive, whereas all 8 herds with a known history of salmonellosis were elisa positive (herd specificity, 0.9 and herd sensitivity, 1.0). A significant correlation (P < 0.001) was found between the OD values of serum and milk samples from cows in the herds with a history of salmonellosis. It was concluded that elisa testing of individual milk samples can be used for surveillance of herds for S typhimurium infections, but further modifications are needed to test bulk tank milk samples.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compare muscle fluid with serum samples for detection of antibodies to Salmonella lipopolysaccharide.

Sample Population

Muscle fluid and serum samples from 2 cattle populations: 1 from the island of Bornholm with no history of salmonellosis (n = 39), and the other from the S dublin-enzootic areas of Jutland (n = 144).

Procedure

Salmonella dublin (O:1,9,12), S typhimu-rium (O:1,4,5,12), and Salmonella O:9-blocking ELISA were used for testing the samples.

Results

In the S dublin ELISA, all serum and muscle fluid samples from cattle on the island of Bornholm had OD450 values well below the cutoff value (0.5). For samples obtained from cattle in the enzootic areas of Jutland, high correlation was found between serum and muscle fluid samples (r s = 0.89, P < 0.001). In addition, 19% (28/144) of the cattle had ELISA-positive muscle fluid and serum samples; 2% (3/144) had positive results for muscle fluid only, whereas 1 animal had positive results for serum only (κ = 0.91, P < 0.0001; sensitivity and specificity of 97%). The same samples had similar significant correlation in the S typhimurium ELISA (r s = 0.88, P < 0.001, κ = 0.7, P < 0.001; sensitivity of 73% and specificity of 98%) and the O:9-blocking ELISA (r s = 0.49, P < 0.001).

Conclusion and Clinical Relevance

Muscle fluid samples taken at slaughter can be used as a practical alternative to serum samples for surveillance of Salmonella infections in cattle. (Am J Vet Res I997;58;334-337)

Free access
in American Journal of Veterinary Research