The CLI specificity was poor under these empirical conditions, producing a false-positive reaction to 42% (n 5 19) of the non-O157:H7 E. coli isolates (four O169:H40 strains [FK-1, OS-2, KS-1, and OS-1], one O157:H45 strain [KPL 300389], one O157:H3 strain [KPL 300489], and two miscellaneous non O157E.coli strains [T884 and PB6472]).However,the seinitial results provided a baseline from which the antibody concentration and incubation time were optimized.