title: Effect of normal intestinal flora of chickens on colonization by virulent colicin V-producing, avirulent, and mutant colicin V-producing avian Escherichia coli.
abstract: Colonization of the intestinal tracts of newly hatched chicks with Escherichia coli was attempted by swabbing test organisms onto the air-shell of 19-day-old embryos. Test organisms consisted of two virulent E. coli isolates, one avirulent isolate, and one laboratory-derived mutant of the avirulent isolate carrying a recombinant plasmid coding for Colicin V production. Chicks were cultured weekly for 3 weeks for total E. coli and for the test organisms using selective media. Control chicks were sampled on weeks 1 and 5, and the normal E. coli intestinal microflora were examined for the production of colicins. The two virulent E. coli isolates maintained colonization of the chicks for the 3-week test period, with titers decreasing from 10' to 10'- colony-forming units (CFU)/g of intestine. The avirulent isolate and laboratory mutant did not consistently colonize the intestinal tracts. The majority of intestinal samples taken from the control chicks at 1 and 5 weeks had colicin-producing E. coli that were inhibitory to the test organisms.
authors.affiliation: Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia Athens 30602.
authors.forename: R E
authors.initials: RE
authors.lastname: Wooley
authors.forename: J
authors.initials: J
authors.lastname: Brown
authors.forename: P S
authors.initials: PS
authors.lastname: Gibbs
authors.forename: L K
authors.initials: LK
authors.lastname: Nolan
authors.forename: K R
authors.initials: KR
authors.lastname: Turner
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002642:Chick Embryo; D002645:Chickens / Q000382:microbiology*; D003087:Colicins / Q000032:analysis / Q000096:biosynthesis*; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology*; D007422:Intestines / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D013045:Species Specificity; D014162:Transfection; D014169:Transformation, Bacterial; D014774:Virulence
chemical_list: D003087:Colicins