ARS | Publication request: COMPARISON OF CULTIVATION TO PCR-HYBRIDIZATION FOR DETECTION OF SALMONELLA IN PORCINE FECAL AND WATER SAMPLES

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2002
Publication Date: May 1, 2002
Citation: Feder, I.E., Nietfeld, J.C., Galland, J., Yeary, T., Sargeant, J.M., Oberst, R., Tamplin, M.L., Luchansky, J.B. 2002. Comparison of cultivation to pcr-hybridization for detection of salmonella in porcine fecal and water samples. American Science and American Dairy Science. Abstract #117 p 28.

Technical Abstract: In the present study, three cultivation techniques were compared to a polymerase chain reaction (PCR)-hybridization technique for the detection of Salmonella. A total of 150 fecal and water samples were tested for the presence of Salmonella: 1) 92 fecal samples were pre-enriched overnight in tryptic soy broth (TSB) followed by overnight enrichment in Rappaport- Vassiliadis R10 (RV10) broth; 2) 34 fecal samples were enriched overnight in RV10 broth with no additional enrichment; and, 3) 24 water samples were pre-enriched overnight in 3MC broth followed by overnight enrichment in RV10 broth. For the PCR detection of Salmonella, samples were tested after the first overnight enrichment. The DNA was extracted via boiling and concentrated using a Sepharose CL-6B spin column. A total of 65 samples tested positive by both cultivation and the PCR or either method alone. Salmonella was detected by both methods in 68.8% of the positive samples pre-enriched in TSB, in 73.3% of the positive samples pre-enriched in 3MC, and in 24.0% of the positive samples enriched in RV10. Using the kappa statistic, agreement was 76% between cultivation with pre-enrichment and the PCR for Salmonella detection but was 5.7% when using cultivation without pre-enrichment compared to the PCR. These data provide evidence that the PCR could be used in combination with cultivation to improve Salmonella detection as the PCR worked as well or better than culture for delineating positive samples. However, the PCR detected only 72% of those samples which culture identified as positive, indicating that additional improvements are warranted before the PCR replaces cultivation as the gold standard for detection of Salmonella from swine.