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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #108500
Title: THE GENETIC DIVERSITY OF PREDOIMINANT ESCHERICHIA COLI STRAINS ISOLATED FROM CATTLE FED VARIOUS AMOUNTS OF HAY AND GRAIN

Author
item JARVIS, GRAEME - CORNELL UNIVERSITY
item KIZOULIS, MENAS - CORNELL UNIVERSITY
item DIEZ-GONZALEZ, FRANCISCO - CORNELL UNIVERSITY
item Russell, James

Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/22/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: When 2 cattle were fed increasing amounts of grain (0 to 90%), volatile fatty acid concentrations increased. Ruminal pH was never less than 6.1, but colonic pH was as low as 5.4. Predominant E. coli strains (n = 44) were isolated from the rumen and colon of cattle on each diet on 4 days. When 16S rDNA genes were PCR-amplified and digested with HhaIII and HaeI, the strains grouped into 4 ribo-patterns, however most strains (75%) had ribo-pattern B. Chromosomal DNA was XbaI-digested, and pulsed-field gel electrophoresis analysis, indicated that the strains formed 4 clades containing 24 distinct genotypes. Genotypes varied with sampling day, but clades were usually the same on 3 or 4 of the days. Interestingly, cow 1 and cow 2 never contained clade III and II strains, respectively. Animal effects masked diet effects, but increasing the amount of grain increased the number of clade II strains in cow 1. When 22 colonic strains were inoculated into a maltose-limited chemostat, only one genotype persisted after 15 days. These results suggest that the genetic diversity of E. coli in the bovine gastrointestinal tract is large, and that different E. coli strains may occupy different niches.