Re. Wooley et al., Inhibition of Salmonella typhimurium in the chicken intestinal tract by a transformed avirulent avian Escherichia coli, AVIAN DIS, 43(2), 1999, pp. 245-250
An avirulent, wild-type avian Escherichia coli (E. coli Av) was electrotran
sformed with a plasmid coding for the production of microcin 24 (pGOB18) an
d was designated E. roll AvGOB18. The transformant inhibited the growth of
seven serotypes of Salmonella commonly associated with colonization and con
tamination of poultry products and seven strains of E. roll O157:H7 in the
in vitro colicin/microcin assay. The transformant did not inhibit the repli
cation of multiple isolates of Listeria monocytogenes or Campylobacter jeju
ni in similar assays. The transformant is nonconjugative, indicating that t
he plasmid would not be transmitted to other intestinal microflora in the e
nvironment. The transformant also survived in sterile tap and deionized wat
er incubated at 25 C and 37 C in the laboratory for 30 days and was recover
ed from drinkers and birds in in vivo floor pen studies. In in vivo studies
, E. coli AvGOB18 did not colonize the intestinal tract of broiler chicks w
hen given as a single or multiple dose and did not reduce the Salmonella lo
ad in the broilers. But Salmonella typhimurium was reduced significantly in
the intestinal tracts of broiler chickens when E, roll AvGOB18 was adminis
tered continually in the water supply.