Selection for urease activity during Helicobacter pylori infection of rhesus macaques (Macaca mulatta)

Helicobacter pylori strain J166 recovered from experimentally inoculated rh esus monkeys had up to a 250-fold-increased urease activity over that befor e inoculation. This was found to result from the selection of urease positi ve J166 clones from a heterogenous inoculum, which aas predominantly urease negative due to a l-bp insertion in the ureA gene, These results confirm t he importance of urease for H, pylori colonization. Strain J166 is particul arly well adapted to the rhesus monkey, since it colonized preferentially d espite the fact that less than 0.1% of the inoculum was urease positive.