The route of transmission for Helicobacter pylori is not well-known,
but one of the suggested possibilities is via drinking water and
associated biofilms. As such, the aim of this work is to study the
influence of several physico-chemical parameters, including temperature,
shear-stress and carbon concentration, on the prevalence and
survival of H. pylori in drinking water biofilms. The biofilm studies
were carried out using a two-stage chemostat system. The outflow
culture of the first vessel fed three secondary chemostats in parallel and
under different conditions of shear stress and carbon concentration.
After 10 days the chemostats reached steady conditions, and the
second stage chemostats were spiked with an inoculum of H. pylori
NCTC 11637 (of approximately 106 cells ml-1) and PVC coupons were
then immersed to allow biofilm formation. The coupons were removed
at different times (up to 32 days) and biofilms detached with sterile
glass beads. Planktonic and sessile cells were quantified by standard
cultivation techniques (R2A and HPSPA) and SYTO9 staining.
Remarkably, H. pylori lost cultivability under all conditions in less
than 1 h which compares with 24-75 h that the pathogen usually takes
to lose cultivability in pure culture at these temperatures. This suggests
that H. pylori is negatively affected by the presence of heterotrophic
microbial consortium; alternatively, overgrowth of other species might
hinder colony development of H. pylori. Current studies are tracking
the uncultivable H. pylori in the biofilms using peptide nucleic acid
probes in a high performance fluorescence in situ hybridisation assay