Successful cultivation of a potentially pathogenic coccoid organism with trophism for gastric mucin

Abstract

We have devised a procedure that permits the cultivation of a gram-positive coccoid species from biopsy material obtained from the antrum of the stomachs of patients with gastric disorders. Antibodies directed against surface proteins obtained from the coccoid isolates were detected in all patients with gastric disorders examined in this study, including both Helicobacter pylori-infected and H. pylori-uninfected patients. Several of these isolates, including a prototype designated strain SL100, have been characterized in some detail. Strain SL100 exhibits urease and exceptionally high catalase activities and assumes a variety of spherical morphologies as detected by electron microscopy. This isolate expresses an adhesin that binds to gastric mucin. The adhesin activity was detected only after the isolate was exposed to an acidic pH, suggesting that in the natural process of infection, the low pH of the stomach unmasks a cell surface component with adhesin activity. Strain SL100 grows best under a microaerophilic conditions (10% CO2, 5% O2, 85% N2), but it also grows quite well under aerobic conditions. Thus, this organism would be expected to proliferate outside of the human host as well as in the gastric mucosa. Oral infection of newborn piglets resulted in colonization of the gastric antrum and growth retardation. Preliminary taxonomic classification indicates similarity to the Staphylococcus DNA homology groups containing S. cohnii and S. xylosus. One of us (C.K.) apparently became infected with this organism as indicated by gastric symptoms and the subsequent presence of strain-specific antisera not present in other workers in the laboratory.