Investigation of the Roles of Toxin-Coregulated Pili and Mannose-Sensitive Hemagglutinin Pili in the Pathogenesis of Vibrio cholerae O139 Infection

In this study, adult volunteers were fed tcpA and mshA deletion mutants of V. cholerae O139 strain CVD 112 to determine the role of toxin-coregulated pili (TCP) and mannose-sensitive hemagglutinin (MSHA) in intestinal colonization. Eight of 10 volunteers who received CVD 112 or CVD 112 Δ mshA shed the vaccine strains in their stools; the geometric mean peak excretion for both groups was 1.4 × 10 5 CFU/g of stool. In contrast, only one of nine recipients of CVD 112 Δ tcpA shed vibrios in his stool ( P < 0.01); during the first 24 h after inoculation, 3 × 10 2 CFU/g was recovered from this volunteer. All recipients of CVD 112 and 8 (80%) of the recipients of CVD 112 Δ mshA developed at least a fourfold rise in vibriocidal titer after immunization. In contrast, only one (11%) of the nine recipients of CVD 112 Δ tcpA developed a fourfold rise in vibriocidal titer ( P < 0.01). We conclude that TCP are an important colonization factor of V. cholerae O139 and probably of El Tor V. cholerae O1. In contrast, MSHA does not appear to promote intestinal colonization in humans.