VARIABLE COLONIZATION OF CHICKENS PERORALLY INOCULATED WITH ESCHERICHIA-COLI O157 H7 AND SUBSEQUENT CONTAMINATION OF EGGS/

Challenging 1-day-old White Leghorn chicks perorally with 2.6 x 10(1) to 2.6 x 10(5) Escherichia coli 0157:H7 bacteria per chick resulted in cecal colonization at all levels. Two of six chicks inoculated with o nly 2.6 x 10(1) E. coli 0157:H7 bacteria carried 10(3) to 10(4) E. col i 0157:H7 bacteria per g of cecal tissue when sacrificed 3 months post inoculation. E. coli 0157:H7 colonization persisted at least 10 to 11 months when chicks were administered 10(8) E. coli 0157:H7 bacteria. E ggs from five hens that were fecal shedders of E. coli 0157:H7 until t he termination of the study (10 to 11 months) were assayed for E. coli 0157:H7. The organism was isolated from the shells of 14 of 101 (13.9 %) eggs but not from the yolks and whites. Considering that chicks can be readily colonized by small populations of E. coli 0157:H7 and cont inue to be long term shedders, it is possible that chickens and hen eg gs can serve as vehicles of this human pathogen.