Maintenance of spiral morphology and formation of biofilms on copper surfaces by water-exposed Helicobacter pylori

Abstract

There is still a lack of consensus on the way Helicobacter pylori is transmitted, but biofilms in drinking water are suspected to create a safe haven for the subsistence of the bacterium and hence promote a waterborne route of infection. Cultivability in water is low when compared to other waterborne pathogens, a situation that is attributed to the conversion of the highly infectious spiral form to the generally regarded as inactive coccoid form of the bacterium. In this study, the adhesion ability to abiotic surfaces (such as copper and PVC), morphology and cultivability of water-exposed H. pylori was assessed. In copper, the bacterium was able to retain spiral morphology and form 3D structures for over two months whereas in PVC conversion to the coccoid form occurred in approximately 1 week. Even though the logical interpretation for these results would be that copper favours the bacterium survival, standard plating experiments have shown precisely the opposite: cultivability decreases faster for the cells exposed to copper. Besides demonstrating the deleterious action that copper surfaces have on H. pylori, this study also indicates that at least for this case, H. pylori coccoid morphology is in fact a manifestation of cell adaptation to the environment.