Shear stress, temperature and inoculation concentration influence on the adhesion of water-stressed Helicobacter pylori to stainless steel 304 and polypropylene

Azevedo, N.F., Pinto, A.R., Reis, N.M., Vieira, M.J. and Keevil, C.W. (2006) Shear stress, temperature and inoculation concentration influence on the adhesion of water-stressed Helicobacter pylori to stainless steel 304 and polypropylene. Applied and Environmental Microbiology, 72 (4), 2936-2941. (doi:10.1128/AEM.72.4.2936-2941.2006).

Abstract

Although molecular techniques have identified Helicobacter pylori in drinking water-associated biofilms, there is a lack of studies reporting what factors affect the attachment of the bacterium to plumbing materials. Therefore, the adhesion of H. pylori suspended in distilled water to stainless steel 304 (SS304) coupons placed on tissue culture plates subjected to different environmental conditions was monitored. The extent of adhesion was evaluated for different water exposure times, using epifluorescence microscopy to count total cell numbers. High shear stresses-estimated through computational fluid dynamics-negatively influenced the adhesion of H. pylori to the substrata (P < 0.001), a result that was confirmed in similar experiments with polypropylene (P < 0.05). However, the temperature and inoculation concentration appeared to have no effect on adhesion (P > 0.05). After 2 hours, H. pylori cells appeared to be isolated on the surface of SS304 and were able to form small aggregates with longer exposure times. However, the formation of a three-dimensional structure was only very rarely observed. This study suggests that the detection of the pathogen in well water described by other authors can be related to the increased ability of H. pylori to integrate into biofilms under conditions of low shear stress. It will also allow a more rational selection of locations to perform molecular or plate culture analysis for the detection of H. pylori in drinking water-associated biofilms.

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Contributors

Author: C.W. Keevil

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