Previous Article | Next Article ![]()
Appl. Environ. Microbiol., Apr 1995, 1363-1370, Vol 61, No. 4
IT Kudva, PG Hatfield and CJ Hovde
The purpose of this study was to develop a sheep model to investigate
reproduction, transmission, and shedding of Escherichia coli O157:H7 in
ruminants. In addition, we investigated the effect of diet change on these
parameters. Six groups of twin lambs given oral inoculations of 10(5) or
10(9) CFU of E. coli O157:H7 and their nondosed mothers were monitored for
colonization by culture of fecal samples. A modified selective-enrichment
protocol that detected E. coli O157:H7 at levels as low as 0.06 CFU per g
of ovine feces was developed. Horizontal transmission of infection occurred
between the lambs and most of the nondosed mothers. When animals were kept
in confinement and given alfalfa pellet feed, lambs receiving the higher
dose shed the bacteria sooner and longer than all other animals. However,
when the animals were released onto a sagebrush-bunchgrass range, every
animal, regardless of its previous status (dosed at one of the inoculum
levels tested or nondosed) shed E. coli O157:H7 uniformly. Shedding
persisted for 15 days, after which all animals tested negative. E. coli
O157:H7 reproduction and transmission and the combined effect of diet
change and feed withholding were also investigated in a pilot study with
experimentally inoculated rams. Withholding feed induced animals to shed
the bacteria either by triggering growth of E. coli O157:H7 present in the
intestines or by increasing susceptibility to infection. Introduction of a
dietary change with brief starvation caused uniform shedding and clearance
of E. coli O157:H7, and all animals then tested negative for the
bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995, American Society for Microbiology
Effect of diet on the shedding of Escherichia coli O157:H7 in a sheep model
Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow 8343, USA.
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|