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

Abstract

Possible multidrug-resistant (MDR) mechanisms of four resistant strains of Escherichia coli to a model β-lactam, ampicillin, were investigated using contact angle measurements of wettability, crystal violet assays of permeability, biofilm formation, fluorescence imaging, and nanoscale analyses of dimensions, adherence, and roughness. Upon exposure to ampicillin, one of the resistant strains, E. coli A5, changed its phenotype from elliptical to spherical, maintained its roughness and biofilm formation abilities, decreased its length and surface area, maintained its cell wall integrity, increased its hydrophobicity, and decreased its nanoscale adhesion to a model surface of silicon nitride. Such modifications are suggested to allow these cells to conserve energy during metabolic dormancy. In comparison, resistant strains E. coli D4, A9, and H5 elongated their cells, increased their roughness, increased their nanoscale adhesion forces, became more hydrophilic, and increased their biofilm formation upon exposure to ampicillin. These results suggest that these strains resisted ampicillin through biofilm formation that possibly introduces diffusion limitations to antibiotics. Investigations of how MDR bacterial cells modify their surfaces in response to antibiotics can guide research efforts aimed at designing more effective antibiotics and new treatment strategies for MDR bacterial infections.

Efficacy of A Poly(MeOEGMA) Brush on the Prevention of Escherichia coli Biofilm Formation and Susceptibility

“…For Enterococcus faecalis (a bacterium responsible for CAUTIs as E. coli and typically susceptible to ampicillin), the formation of a complex 3D-biofilm structure in presence of antibiotics was also associated with a stress response of enterococcal biofilm cells, which promoted a rapid reorganization of biofilm into highly structured microcolonies [55]. A recent work evaluated the effects of ampicillin on surface modifications of four multidrug-resistant E. coli strains and concluded that three of them suffered cell elongation, an increase in roughness and nanoscale adhesion forces, became more hydrophilic and increased biofilm formation [56].…”

Mechanistic Understanding of the Interactions of Cationic Conjugated Oligo- and Polyelectrolytes with Wild-type and Ampicillin-resistant Escherichia coli

“…The ratios of phenyl groups to quaternary amine groups in CCPE, 2QA-CCOE, and 4QA-CCOE were 1: 1, 3: 2, and, 3: 4, respectively. Prior reports showed evidence of changes in cell elasticity, hydrophilic/hydrophobic interactions, nanoscale morphology, and membrane permeability when β-lactam resistant E. coli were treated with ampicillin 36 . Even different strains of amp-resistant E. coli can exhibit different phenotypical traits 36 .…”

“…Prior reports showed evidence of changes in cell elasticity, hydrophilic/hydrophobic interactions, nanoscale morphology, and membrane permeability when β-lactam resistant E. coli were treated with ampicillin 36 . Even different strains of amp-resistant E. coli can exhibit different phenotypical traits 36 . Since the cell-drug interaction is highly dependent on the type of strains as well as the drug molecules used, it is critical to explore the interactions of conjugated small and large molecules with both wild-type and amp-resistant bacterial strains side-by-side.…”

Alterations in the Cell Wall of Rhodococcus biphenylivorans Under Norfloxacin Stress

“…In previous studies, the surface roughness of Escherichia coli cells after ampicillin treatment increased significantly, which may contribute to bacterial cells adhesion to model surfaces. Moreover, biofilm formation ability was also enhanced, promoting the survival of cells in adverse environments ( Uzoechi and Abu-Lail, 2019 ). Therefore, the increase in cell wall surface roughness could be caused by the toxicity of norfloxacin, or may be one of the reasons for TG9 being tolerant to antibiotics in the VBNC state.…”