Coccoid Forms of Helicobacter pylori

To the Editor?Eaton et al. [1] recently described experiments with coccoid Helicobacter pylori in gnotobiotic piglets. This interesting study examined the colonization and the reversion from coccoid to bacillary H. pylori within 2 weeks of inoculation. Piglets colonized with bacillary H. pylori had more severe gastritis 2 weeks after inoculation than did those sacrificed 1 week after inoculation. The coccoid H. pylori did not colonize stomachs and did not lead to histopathologic changes. Our experience with coccoid H. pylori inoculated intragastrically in a similar experimental design in BALB/c mice differed [2]. Concentrated coccoid (^550 = 5 McFarland units) H. pylori cultures (20 days of incubation), not culturable in vitro (0 cfu/mL), showed colonization and produced gastric alteration with a peak 4 weeks after inoculation. In our studies, the histologic changes obtained with fresh coccoid H. pylori were lower than those in mice infected with the same strains in bacillary morphology, probably due to partial reversion of the coccoid bacteria and therefore smaller concentrations of