Fig. 1.

Enterotoxigenic Escherichia coli (ETEC) infection inhibits thiamin uptake by confluent Caco-2 monolayers. A: Caco-2 cells at 3–4 days after confluency were serum starved (overnight) then infected with wild-type ETEC at different multiplicity of infection (MOI; 50, 100, and 200) or with nonpathogenic E. coli (HS4) at MOI of 200 for 3 h. Uptake of thiamin was subsequently measured as described in Methods. *P < 0.01, compared with control. B: effect of ETEC (at 200 MOI, 3 h) on [³H]biotin uptake by Caco-2 cells.