Effect of dilution factor on the isolation of Helicobacter pylori from municipal wastewater using culture technique

Background and Objectives: Isolating Helicobacter pylori (H. pylori) from wastewater and culturing it using a convention- al method has always been acontroversial issue because the bacterium converts into a coccoid form when exposed to an un- favourable environment like wastewater. To clarify thecultivability behaviour of the bacterium in fresh wastewater samples, the effect of municipal wastewater dilation on the cultivation of the bacterium using a conventional method was examined. 
Materials and Methods: Several dilutions of wastewater samples were inoculated with fresh H. pylori suspension(with McFarland's dilution 0.5) to examine the dilution effect of wastewater on the bacterium isolation. 
Results: The H. pylori growth was found to be possible for a dilution factor from 1/106 to 1/107 of raw wastewater. In higher dilution factors the growth of fungi was dominant and could prevent the isolation of the bacterium. 
Conclusion: The optimized technique could be applied in future studies for increasing the chance of H. pylori isolation from fresh wastewater environments.