Impact of the β-Lactam Resistance Modifier (−)-Epicatechin Gallate on the Non-Random Distribution of Phospholipids across the Cytoplasmic Membrane of Staphylococcus aureus

Abstract

The polyphenol (−)-epicatechin gallate (ECg) inserts into the cytoplasmic membrane (CM) of methicillin-resistant Staphylococcus aureus (MRSA) and reversibly abrogates resistance to β-lactam antibiotics. ECg elicits an increase in MRSA cell size and induces thickened cell walls. As ECg partially delocalizes penicillin-binding protein PBP2 from the septal division site, reduces PBP2 and PBP2a complexation and induces CM remodelling, we examined the impact of ECg membrane intercalation on phospholipid distribution across the CM and determined if ECg affects the equatorial, orthogonal mode of division. The major phospholipids of the staphylococcal CM, lysylphosphatidylglycerol (LPG), phosphatidylglycerol (PG), and cardiolipin (CL), were distributed in highly asymmetric fashion; 95%–97% of LPG was associated with the inner leaflet whereas PG (~90%) and CL (~80%) were found predominantly in the outer leaflet. ECg elicited small, significant changes in LPG distribution. Atomic force microscopy established that ECg-exposed cells divided in similar fashion to control bacteria, with a thickened band of encircling peptidoglycan representing the most recent plane of cell division, less distinct ribs indicative of previous sites of orthogonal division and concentric rings and “knobbles” representing stages of peptidoglycan remodelling during the cell cycle. Preservation of staphylococcal membrane lipid asymmetry and mode of division in sequential orthogonal planes appear key features of ECg-induced stress.

Increased resistance of a methicillin-resistant Staphylococcus aureus Δagr mutant with modified control in fatty acid metabolism

“…On the other hand, accumulation of long chain fatty acids decrease membrane permeability and increase membrane stability (Uzman 2003). These changes might have affected the antibiotic resistance of Δagr mutant strain since physiology of phospholipid affect the antibiotic resistance (Rosado et al 2015). Moreover, we showed span20 could affect the antibiotic susceptibility of MRSA in a complicated manner by changing membrane stability.…”

Epicatechin gallate, a naturally occurring polyphenol, alters the course of infection with β-lactam-resistant Staphylococcus aureus in the zebrafish embryo

“…Growth in liquid medium containing ECg has a significant, reversible impact on the minimum inhibitory concentration (MIC) of β-lactam antibiotics against EMRSA-16 and other resistant strains of S. aureus ( Stapleton et al, 2004 ). For example, after 4 h growth in 12.5 μg/mL of ECg, the MIC of EMRSA-16 for oxacillin is reduced from 512 to 1 μg/mL ( Rosado et al, 2015 ). We therefore investigated the impact of exposure to ECg alone and ECg in combination with oxacillin on the survival of 30 hpf embryos; the concentrations of oxacillin employed reflected those that were efficacious following conversion of EMRSA-16 to phenotypic susceptibility by ECg in vitro .…”

“…In common with catechins and other catechin gallates, ECg shows a strong tendency to partition into lipid bilayers, including model lipid bilayers comprising single phospholipid species and more complex biological membranes such as the staphylococcal cytoplasmic membrane (CM) ( Caturla et al, 2003 ; Bernal et al, 2010 ). ECg penetrates deep into the hydrophobic core of the lipid palisade of the staphylococcal bilayer to induce a comprehensive reconfiguration of membrane architecture ( Palacios et al, 2014 ; Rosado et al, 2015 ), providing a suboptimal environment for the cell wall biosynthetic and cell division machineries. Thus, intercalation of ECg into the staphylococcal CM leads to increased cell wall thickness ( Stapleton et al, 2007 ) and increases in the net negative charge at the bacterial surface due to reductions in D -alanylation of wall teichoic acid ( Bernal et al, 2009 ) and lysylation of phosphatidylglycerol head groups ( Bernal et al, 2010 ; Rosado et al, 2015 ).…”

“…ECg penetrates deep into the hydrophobic core of the lipid palisade of the staphylococcal bilayer to induce a comprehensive reconfiguration of membrane architecture ( Palacios et al, 2014 ; Rosado et al, 2015 ), providing a suboptimal environment for the cell wall biosynthetic and cell division machineries. Thus, intercalation of ECg into the staphylococcal CM leads to increased cell wall thickness ( Stapleton et al, 2007 ) and increases in the net negative charge at the bacterial surface due to reductions in D -alanylation of wall teichoic acid ( Bernal et al, 2009 ) and lysylation of phosphatidylglycerol head groups ( Bernal et al, 2010 ; Rosado et al, 2015 ). Most importantly, ECg intercalation delocalizes PBP2 from the septal site of cell division ( Bernal et al, 2010 ) and disrupts the functional integrity of the cell division assemblage, the divisome ( Paulin et al, 2014 ).…”

Physical Characteristics of the Leaves and Latex of Papaya Plants Infected with the Papaya meleira Virus

“…The surfaces of the midribs and latex of the PMeV-infected plants showed regions with prominent ridges, deep valleys, and a rough microstructure ( Figure 1 and Figure 2 ). Some components of the plant tissue act as first signals of infection and offer a certain level of protection against pathogens and abiotic stress [ 17 , 18 , 19 ]. However, PMeV can bypass the innate host defenses systems by altering the physical characteristics of the leaf midribs and latex of papaya plants.…”