Helicobacter in water and waterborne routes of transmission

Helicobacter pylori is the causative agent of gastritis and duodenal ulcers and plays a role in the development of gastic cancer. The transmission of H. pylori remains unclear but two different pathways have been suggested: faecal-oral and oral-oral. Studies from developing countries with low socioeconomic status and poor management of the drinking water suggest that environmental factors are important. Thus, the water mal serve as a reservoir for H. pylori that infect humans. Viable but non-culturable bacteria are widespread in marine environments. The coccoid form of H. pylori in non-culturable by ordinary techniques and it remains to be studied whether this form is viable. Several studies have been performed to assess the viability of H. pylori in water since it has been suggested that the coccoid form of H. pylori is responsible for transmission in the environment, probably via contaminated water. Different DNA-based methods have been used to detect Helicobacter spp. in water. Target genes have been selected to avoid cross-reactivity between H. pylori and other bacteria. However, closely related bacteria and unknown subspecies of Helicobacter spp. may confound the 'species-specific' DNA-based assays and must be considered if controversial results appear in analyses of environmental samples.