Genotypic and phenotypic analysis of Salmonella strains associated with an outbreak of equine neonatal salmonellosis.
Isolates of Salmonella choleraesuis serotype ohio (S. ohio) recovered during an outbreak of equine neonatal salmonellosis on a Thoroughbred farm were compared with isolates of the same serotype from various animal, feed and environmental sources. Biochemical profiles, antimicrobial susceptibility patterns, phage susceptibility, plasmid profiles, restriction endonuclease analysis and ribotyping were used to compare relatedness of the strains. A total of 46 outbreak and non-outbreak associated isolates of S. ohio were studied. Differences in antimicrobial susceptibility patterns, phage susceptibility and plasmid profiles were useful for differentiating outbreak isolates from other equine isolates as well as bovine, porcine and some poultry isolates. Feed and other poultry isolates, most in geographic proximity to the outbreak, were indistinguishable from outbreak isolates by any of the methods employed. Investigative studies on the farm along with results of genotypic and phenotypic analysis of isolates suggested that contaminated feed was the most likely source of Salmonella in this outbreak.
Walker
R L
RL
California Veterinary Diagnostic Laboratory, University of California, Davis 95616, USA.
de Peralta
T L
TL
Villanueva
M R
MR
Snipes
K P
KP
Madigan
J E
JE
Hird
D W
DW
Kasten
R W
RW
D000818:Animals; D001435:Bacteriophages / Q000302:isolation & purification; D004262:DNA Restriction Enzymes / Q000032:analysis; D004269:DNA, Bacterial; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D005838:Genotype; D006734:Horse Diseases / Q000453:epidemiology / Q000382:microbiology*; D006736:Horses; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D010641:Phenotype; D010957:Plasmids / Q000032:analysis; D012475:Salmonella / Q000235:genetics*; D012481:Salmonella Infections, Animal / Q000453:epidemiology / Q000382:microbiology*
D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes