Shear Stress, Temperature, and Inoculation Concentration Influence the Adhesion of Water-Stressed Helicobacter pylori to Stainless Steel 304 and Polypropylene

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.

Analysis of Fluid Flow and Wall Shear Stress Patterns Inside Partially Filled Agitated Culture Well Plates

“…2,15,28,31 These compact devices, facilitate multi-sample testing, provide oscillatory fluid motion with adjustable speeds and do not require bulky pump-flow cell-tubing setups and problems associated with them in terms of manufacturing and sealing. Also, the relatively large and flat surfaces of each well provide easy access for optical measurements, microscopy and other analysis.…”

Coccoid Form of Helicobacter pylori as a Morphological Manifestation of Cell Adaptation to the Environment

“…For all strains, the number of culturable cells on the surface increased up to 10 4 to 10 6 CFU/cm 2 in the first 2 h due to the initial adhesion process. Even though it has been previously shown that the total number of cells adhered continues to rise until 48 h (3,5), culturable cell numbers started to decrease after only 2 hours (for polyvinyl chloride [PVC] and glass and strain J99, the numbers stabilized). This effect was partly expected, as the culturability time for H. pylori in water at this temperature is quite low (1, 4).…”

“…Nevertheless, biofilms are prolific in microenvironments, and the possibility of areas where the bacterium survives cannot be excluded. Future work on screening different types of surface-related microenvironments will allow confirmation of hypotheses developed on the data already acquired on pure culture studies (3,5) and in developing new hypotheses. Finally, this study also brings new insights to the H. pylori transmission debate.…”

“…One of the problems encountered in earlier studies was to actually recover culturable H. pylori at statistically meaningful levels from abiotic surfaces using standard methods (3,5). It has been found that H. pylori is particularly sensitive to sonication and that a 5-s burst at 25% amplitude (GEX 400 ultrasonic processor; Sigma) optimized recovery as opposed to the 1-min cycles more often used in the laboratory to detach and recover microorganisms from heterotrophic biofilms.…”

Quantitative Detection of &lt;i&gt;Helicobacter pylori&lt;/i&gt; by Real Time PCR in Drinking Water—Environmental and Public Health Risk Significance

“…In particular, Azevedo and colleagues [28] [44] [45] have worked with biofilms in pipes and water deposits, and they consider this to be the way bacteria can remain viable in the water. Additionally, biofilms developed by multiple H. pylori strains are, in general terms, more complex than those associated with single strains; such condition might promote the genetic exchange favoring the generation of more virulent strains [46].…”