SUSCEPTIBILITY OF 3 STRAINS OF CONVENTIONAL ADULT MICE TO INTESTINAL COLONIZATION BY AN ISOLATE OF ESCHERICHIA-COLI O157 H7/

Three mouse strains were assessed for their susceptibility to intestin al colonization by a strain of the enteric bacterial pathogen Escheric hia coli O157:H7. Following intragastric inoculation of E. coli O157:H 7, the intestines of young adult female CD1, BALB/c, and C57BL/6 mice became colonized, as evidenced by faecal shedding of the pathogen for periods of up to 5 weeks. None of the three mouse strains examined dev eloped overt disease in response to colonization by the organism. Foll owing clearance of the primary inoculum, BALB/c mice, but not CD1 or C 57BL/6 mice, appeared to acquire enhanced resistance to recolonization by E. coli O157:H7, as evidenced by a decreased faecal shedding perio d. This enhanced resistance correlated with the presence and persisten ce of immunoglobulin A, but not immunoglobulin G, in the serum and fae ces directed against the O157 antigen. The implications of these findi ngs to vaccine development against E. coli O157:H7 are discussed.