Refinement of the CS6-expressing enterotoxigenic Escherichia coli strain B7A human challenge model: A randomized trial.

ABSTRACT:

Background

Human challenge models for enterotoxigenic Escherichia coli (ETEC) facilitate vaccine down-selection. The B7A (O148:H28 CS6+LT+ST+) strain is important for vaccine development. We sought to refine the B7A model by identifying a dose and fasting regimen consistently inducing moderate-severe diarrhea.

Methods

An initial cohort of 28 subjects was randomized (1:1:1:1) to receive B7A following an overnight fast at doses of 108 or 109 colony forming units (cfu) or a 90-minute fast at doses of 109 or 1010 cfu. A second cohort included naïve and rechallenged subjects who had moderate-severe diarrhea and were given the target regimen. Immune responses to important ETEC antigens were assessed.

Results

Among subjects receiving 108 cfu of B7A, overnight fast, or 109 cf

SUBMITTER: Talaat KR 

PROVIDER: S-EPMC7710093 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature