Temporal study of Helicobacter pylori presence in coastal freshwater, estuary and marine waters

Helicobacter pylori, a gastric pathogen, is believed to be transmitted via the fecal-oral route as well as the oral-oral route. Its presence and viability in environmental waters is not well characterized. The goals of this study were to test H. pylori presence via molecular methods in freshwater, estuarine and beach sites in Delaware over both short and long time scales and to establish whether fecal indicator bacteria, including total Enterococcus and human-specific Bacteroidetes species, are predictive of the pathogen in these waters. The presence of Helicobacter pylori was initially tested by PCR with newly designed 23S rRNA gene primers against Helicobacter spp. and confirmed by sequencing. Two coastal beach sites were repeatedly positive in 2007. Clone library analysis indicated the persistence of one operational taxonomic unit (OTU) over time at one site. Detection of H. pylori was also determined by PCR assays from DNA and RNA for the 16S rRNA gene, as well as DNA for the ureA and cagA genes. Approximately 21% of the samples were positive for H. pylori 16S rRNA gene and 80% of those were also positive for H. pylori 16S rRNA, indicating that this potential pathogen is not only present in natural waters, but also probably viable. There was no correlation between the occurrence of H. pylori and fecal indicator bacteria, suggesting that standard water quality tests are ineffective in predicting the presence of this pathogen in natural waters. These results demonstrate the widespread presence of potentially viable H. pylori in coastal marine and estuarine waters. Additionally, the repeatedly positive samples indicate either a continual contamination source or persistence of H. pylori in marine waters.

Research highlights
► We describe sensitive and specific primers that detect H. pylori in environmental waters.
► Approximately 20% of Delaware coastal waters contain H. pylori.
► Intact H. pylori was assessed by the presence of rRNA.
► There is no correlation between H. pylori and fecal indicator bacterial presence.