FIG. 1.

The effect of oral phage treatment on E. coli O157:H7 in mice. Two groups of three mice (control 1 and phage 1) received a single oral dose of 10⁸ CFU E. coli O157:H7 ATCC 43894 on day −1. On days 0, 1, and 2, mice in phage treatment group 1 were given an oral dose of 10¹⁰ PFU of SH1 phage. Another two groups of three mice (control 2 and phage 2) received a single oral dose of 10⁸ CFU E. coli O157:H7 containing equal numbers of four strains (ATCC 43894, WSU180, WSU400, and WSU 588) on day −1. On days 0, 1, and 2 the treated mice were given oral doses of 10¹⁰ PFU of both SH1 and KH1. Untreated control mice received 100 μl of a mock bacterial lysate without phage. Data points below E+ indicate samples positive for E. coli O157:H7 only by an enrichment procedure and with total numbers <10 CFU/fecal pellet. Standard errors ranged from 0.5 log to 1.2 logs. Neg indicates RAMS cultures that were negative by both direct and enrichment culture procedures.