Bacterial Stress Responses as Determinants of Antimicrobial Resistance

and, Michael Fruci; Poole, Keith

doi:10.1002/9781119004813.ch10

Cited by 9 publications

(8 citation statements)

References 264 publications

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“…The bacterial outer membrane can be regulated by changes in the surrounding environment. In a stress-free environment, cells use nutrients to divide, grow to mature, and produce toxins and products (Fruci & Poole, 2016). In the case of stress, like that imposed by ampicillin, they shift their use of nutrients to getting more SA, producing toxins and/or avoiding division (Cho & Bernhardt, 2014).…”

Section: Discussionmentioning

confidence: 99%

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

Uzoechi

Abu-Lail

2019

Microsc Microanal

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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.

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Section: Discussionmentioning

confidence: 99%

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

Uzoechi

Abu-Lail

2019

Microsc Microanal

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“…Due to their widespread use, Gram-negative bacteria such as Escherichia coli developed complex means to resist these antibiotics ( Shaikh et al, 2015 ). Research has shown that bacterial resistance to antibiotics is encoded in genetics mechanisms; several of which involve the production of hydrolyzing enzymes involved in the hydrolysis of β-lactam ring, modification of the target sites to antibiotics such as changes in the penicillin-binding protein (PBP) resulting in decreased affinity to β-lactams, production of efflux pumps on the cell membrane to expel antibiotics outside the cell, and production of key extracellular polymeric substances (EPS) that affect the formation of biofilms capable of impeding the diffusion of antibiotics into biofilms ( Aeschlimann, 2003 , Babic et al, 2006 , Yang et al, 2006 , Mohanty et al, 2012 , Read and Woods, 2014 , Fruci and Poole, 2016 ). These complex and interdependent mechanisms employed by resistant bacterial cells to withstand antibiotics are held responsible for the current challenges faced in controlling their infections ( Aeschlimann, 2003 , Babic et al, 2006 , Yang et al, 2006 , Mohanty et al, 2012 , Read and Woods, 2014 , Fruci and Poole, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

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

Uzoechi

Abu-Lail

2019

The Cell Surface

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The roles of the thicknesses and grafting densities of the surface biopolymers of four multi-drug resistant (MDR) Escherichia coli bacterial strains that varied in their biofilm formation in controlling cellular elasticities after exposure to ampicillin were investigated using atomic force microscopy. Exposure to ampicillin was carried out at minimum inhibitory concentrations for different duration times. Our results indicated that the four strains resisted ampicillin through variable mechanisms. Strain A5 did not change its cellular properties upon exposure to ampicillin and as such resisted ampicillin through dormancy. Strain H5 increased its biopolymer brush thickness, adhesion and biofilm formation and kept its roughness, surface area and cell elasticity unchanged upon exposure to ampicillin. As such, this strain likely limits the diffusion of ampicillin by forming strong biofilms. At three hours’ exposure to ampicillin, strains D4 and A9 increased their roughness, surface areas, biofilm formation, and brush thicknesses and decreased their elasticities. Therefore, at short exposure times to ampicillin, these strains resisted ampicillin through forming strong biofilms that impede ampicillin diffusion. At eight hours’ exposure to ampicillin, strains D4 and A9 collapsed their biopolymers, increased their apparent grafting densities and increased their cellular elasticities. Therefore, at long exposure times to ampicillin, cells utilized their higher rigidity to reduce the diffusion of ampicillin into the cells. The findings of this study clearly point to the potential of using the nanoscale characterization of MDR bacterial properties as a means to monitor cell modifications that enhance “phenotypic antibiotic resistance”.

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“…In 2006, using scanning electron microscopy (SEM), Carron et al first proposed that H. pylori could form biofilms in vivo ( 9 ). The formation of biofilms in vivo is an important cause of H. pylori resistance to multiple antibiotics ( 10 ), as is its stringent response to a stressful environment lacking nutrients ( 11 ).…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Enzyme SpoT Is Involved in Biofilm Formation of Helicobacter pylori with Multidrug Resistance by Upregulating Efflux Pump Hp1174 ( gluP )

Cai

Chen

et al. 2018

Antimicrob Agents Chemother

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Bacterial Stress Responses as Determinants of Antimicrobial Resistance

Cited by 9 publications

References 264 publications

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

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

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

Bifunctional Enzyme SpoT Is Involved in Biofilm Formation of Helicobacter pylori with Multidrug Resistance by Upregulating Efflux Pump Hp1174 ( gluP )

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