E.coli

Aim of this study was to select environmental E. coliisolates that produced colicins against the swine pathogen E. coliK88+. In initial evaluation using a modified plate method with 18colicinogenic E. coli constructs, colicins E3, E4, E5, E9, Ia, Kand N were found to possess inhibitory activity against 12 ETECK88+ strains. A total of 463 environmental isolates from cattlerumen, cattle feces, pig feces and hog manure-amended soil werescreened for colicin production by a modified plate test.Further,colicinogenic isolates were screened for five toxin genesLT, STa, STb, VT1 and VT2 as well as K88 (F4) fimbriae using PCRreactions. Fourteen non-pathogenic isolates were subjected tocharacterization of colicin genes by PCR using 9 new primersequences, antibiotic susceptibilities and substrate utilization.Two potential probiotic strains of E. coli, UM-2 and UM-7 whichproduced colicins that could utilize potato starch and inulin wereselected for in-vitro competition with E. coli K88+ strain 2-12. Invitro competition between the synbiotics and E. coli K88+ revealedinhibition of E. coli K88+. Animal testing of these strains iscurrently being undertaken.