Using Atomic Force Microscopy to Measure Anti-Adhesion Effects on Uropathogenic Bacteria, Observed in Urine after Cranberry Juice Consumption

Abstract

A volunteer was given cranberry juice cocktail (CJC) or water to drink, and urine was collected at 2 and 8 hours after consumption, in order to quantitatively determine whether adhesion forces were changed for the volunteer after CJC consumption. Atomic force microscopy (AFM) was used to measure adhesion forces between bacteria and a silicon nitride tip. Forces between Escherichia coli or Staphylococcus aureus and the AFM tip were lower in the urine after the volunteer consumed CJC, compared to drinking water. A steric model was applied to the AFM data, in order to quantify how the urine changed the properties of the bacterial surfaces. There was a small decrease in the equilibrium length of surface molecules on the bacteria when in the post-CJC urine, compared to the post-water urine. However, these changes were not statistically significant. We hypothesize that post-CJC urine imparts subtle changes on the molecules of the bacterial surfaces, and that these changes lead to the reduction in adhesion with the AFM probe.

The Effects of β-Lactam Antibiotics on Surface Modifications of Multidrug-Resistant Escherichia coli: A Multiscale Approach

“…Bacterial adhesion to surfaces is one of the main mechanisms employed by bacterial cells for variable functions including access to nutrients, building a biofilm community and having an improved antibiotics resistance (Donlan, 2002; Garrett & Zhang, 2008). Due to its vitality to cell function, many techniques, as well as studies, were devoted to quantifying cell adhesion (Abu-Lail & Camesano, 2003; Park & Abu-Lail, 2011 a , 2011 b ; Abu-Lail, 2012; Khalili & Ahmad, 2015). Some of these techniques quantify the adhesion of individual cells to surfaces and some quantify biofilm formation of cells (Abu-Lail & Camesano, 2003; Liu et al, 2006; Camesano et al, 2007; Wright et al, 2010; Abu-Lail, 2012; Huang et al, 2015).…”

“…AFM measurements were carried out on cells using the most commonly available cantilevers, Si 3 N 4 . These cantilevers provide a base model to which bacterial adhesion can be quantified (Abu-Lail & Camesano 2003; 2012; Gordesli & Abu-Lail, 2012), as well as differences in physiochemical properties of bacterial cells such as roughness (Alves et al, 2010). Dimensions (Yang et al, 2006) can be compared across investigated strains in response to exposure to ampicillin.…”

Changes in cellular elasticities and conformational properties of bacterial surface biopolymers of multidrug-resistant Escherichia coli (MDR-E. coli) strains in response to ampicillin

“…This study aimed at investigating how MDR- E. coli strains modify their mechanical properties represented in terms of the bacterial surface biopolymer brushes’ thicknesses and grafting densities as well as bacterial cells’ elasticities upon exposure to ampicillin for different time durations at their respective MICs. To our knowledge, very few studies in the literature investigated the effects of antibiotics ( Perry et al, 2009 , Longo et al, 2013a , Longo et al, 2013b ) and/or their related agents ( Liu et al, 2006 , Camesano et al, 2007 , Abu-Lail, 2012 , Algré et al, 2014 ) on the properties listed above and they were only performed on susceptible bacterial cells to antibiotics. It is worth noting that these studies did not investigate the mechanical properties of MDR bacterial cells.…”

Modelling of the normal elastic dissipative interaction of a S. Aureus Bacterium

“…Physical experiments with AFM give information on the force-displacement hysteresis behaviour of the S. aureus bacterium, see [7], [8]. The objective of the work here is to describe and take into account the experimentally observed dissipative behaviour into a model for the investigated bacterium.…”