ISSN:
1573-7446
Keywords:
antibiotic resistance
;
cattle
;
delayed secondary enrichment
;
detection
;
faeces
;
primary enrichment
;
Salmonella
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
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 forSalmonella-like growth. Suspect colonies were further tested andSalmonella isolates were serotyped by the National Veterinary Services laboratory. Twenty-two of the 36 calves sampled harbouredS. typhimurium in their faeces, but no samples from cows were positive. NoSalmonella were isolated from the buffy coats, but 4 calves were shown to haveSalmonella in their nasal secretions. Extended enrichment of the faecal cultures in TB resulted in a significant increase inSalmonella isolations, although 2 samples were positive following the initial enrichment period and not after secondary enrichment. The typicalSalmonella 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 ofSalmonella from cattle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01839246
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