Detection and characterization of Salmonella typhimurium from a dairy herd in North Dakota

L. K. Nolan, C. W. Giddings, E. W. Boland, D. J. Steffen, J. Brown, A. Misek

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Nasal secretions, faecal samples and buffy coats were obtained from 102 cattle from a North Dakota dairy herd with a history of calf scours. Treated buffy coats, faecal samples and nasal secretions were inoculated into tetrathionate broth (TB), incubated at 37°C overnight, and plated onto brilliant green agar medium with novobiocin (BGAN). The TB was left at room temperature for 5 days and then used to inoculate fresh TB. The fresh TB was incubated at 37°C over night and plated onto BGAN medium. All the plates were incubated at 37°C over night and observed for Salmonella-like growth. Suspect colonies were further tested and Salmonella isolates were serotyped by the National Veterinary Services laboratory. Twenty-two of the 36 calves sampled harboured S. typhimurium in their faeces, but no samples from cows were positive. No Salmonella were isolated from the buffy coats, but 4 calves were shown to have Salmonella in their nasal secretions. Extended enrichment of the faecal cultures in TB resulted in a significant increase in Salmonella isolations, although 2 samples were positive following the initial enrichment period and not after secondary enrichment. The typical Salmonella isolate detected from this herd contained a transmissible R-plasmid encoding resistance to tetracycline, kanamycin, sulphisoxazole and ampicillin. This study confirmed that delayed secondary enrichment in TB is superior to primary enrichment for detection of Salmonella from cattle.

Original languageEnglish (US)
Pages (from-to)3-8
Number of pages6
JournalVeterinary Research Communications
Volume19
Issue number1
DOIs
Publication statusPublished - Jan 1 1995

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Keywords

  • Salmonella
  • antibiotic resistance
  • cattle
  • delayed secondary enrichment
  • detection
  • faeces
  • primary enrichment

ASJC Scopus subject areas

  • veterinary(all)

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