The suckling mouse has been used as a model to identify Vibrio cholerae int
estinal colonization factors for over two decades, yet little is known abou
t the location of recoverable organisms along the gastrointestinal (GI) tra
ct following intragastric inoculation. In the present study, we determined
the population dynamics of wild-type and avirulent mutant derivatives of bo
th classical and Fl Tor biotype strains throughout the entire suckling mous
e GI tract at various times after intragastric inoculation. Wild-type strai
ns preferentially colonized the middle small bowel with a sharp demarcation
between more proximal segments which had manyfold-fewer recoverable cells.
Surprisingly, large and stable populations of viable cells were also recov
ered from the cecum and large bowel. Strains lacking toxin-coregulated pill
(TCP-) were cleared from the small bowel; however, an El Tor TCP- strain c
olonized the cecum and large bowel almost as well as the wild-type strain.
Strains lacking lipopolysaccharide O antigen (OA(-)) were efficiently clear
ed from the small bowel at early times but then showed net growth for the r
emainder of the infections. Moreover, large populations of the OA(-) strain
s were maintained in the large bowel. These results show that for the El To
r biotype neither TCP nor OA is required for colonization of the suckling m
ouse large bowel. Finally, similar percent recoveries of wild-type, TCP-, a
nd OA(-) strains from the small bowel at an early time after infection sugg
est that TCP and OA are not required for strains of either biotype to resis
t bactericidal mechanisms in the suckling mouse GI tract.