scholarly journals Evolution of Daptomycin Resistance in Coagulase-Negative Staphylococci Involves Mutations of the Essential Two-Component Regulator WalKR

2019 ◽  
Vol 63 (3) ◽  
Author(s):  
Jhih-Hang Jiang ◽  
Carina Dexter ◽  
David R. Cameron ◽  
Ian R. Monk ◽  
Sarah L. Baines ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Cell Surface ◽  
Surface Charge ◽  
Sequencing Analysis ◽  
Care Hospital ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Staphylococcus Capitis ◽  
Cell Surface Charge ◽  
Two Component

ABSTRACTCoagulase-negative staphylococci (CoNS) represent one of the major causes of health care- and medical device-associated infections. Emerging antimicrobial resistance has complicated the treatment of systemic infections caused by CoNS. Here, we describe the prevalence of antimicrobial resistance in clinical CoNS strains from a tertiary care hospital over a 4-year period, and we observed a significant increase in resistance to daptomycin. Notably,Staphylococcus capitisaccounted for the majority of these daptomycin-resistant (DAP-R) CoNS. To further investigate the mechanisms of daptomycin resistance in CoNS, daptomycin-susceptible clinical strains ofS. capitisandStaphylococcus epidermidisunderwentin vitrodaptomycin exposure to generate DAP-R CoNS mutants. Unlike that seen withStaphylococcus aureus, alteration of cell surface charge was not observed in the DAP-R CoNS strains, but biofilm formation was compromised. Whole-genome sequencing analysis of the DAP-R CoNS strains identified single nucleotide polymorphisms (SNPs) inwalKR, the essential two-component regulatory system controlling cell wall biogenesis. PCR and sequencing ofwalKandwalRfrom 17 DAP-R CoNS clinical isolates identified seven nonsynonymous mutations. The results were confirmed by the recreation of thewalKSNP inS. epidermidis, which resulted in reduced susceptibility to daptomycin and vancomycin. This study highlights the significance of CoNS in evolving daptomycin resistance and showed thatwalKRis shared among the staphylococcal species and is involved in antibiotic resistance development. Notably, we did not observe mutations in genes responsible for phospholipid biosynthesis or an altered cell surface charge, suggesting that reduced daptomycin susceptibility in CoNS may emerge in a fashion distinct from that inS. aureus.

scholarly journals Fosfomycin Enhances the Activity of Daptomycin against Vancomycin-Resistant Enterococci in anIn VitroPharmacokinetic-Pharmacodynamic Model

2016 ◽  
Vol 60 (10) ◽  
pp. 5716-5723 ◽  
Author(s):  
Ashley D. Hall Snyder ◽  
Brian J. Werth ◽  
Poochit Nonejuie ◽  
John P. McRoberts ◽  
Joe Pogliano ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Charge ◽  
Content Type ◽  
Cell Surface Charge ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
High Doses ◽  
Zeta Potential Analysis

ABSTRACTDaptomycin (DAP) is being used more frequently to treat infections caused by vancomycin-resistant enterococcus (VRE). DAP tends to be less active against enterococci than staphylococci and may require high doses or combination therapy to be bactericidal. Fosfomycin (FOF) has activity against VRE and has demonstrated synergistic bactericidal activity with DAPin vitro. The objective of this study was to evaluate the activity of DAP alone and in combination with FOF against VRE in anin vitropharmacokinetic/pharmacodynamic (PK/PD) model. The activity of DAP at 8 and 12 mg/kg of body weight/day (DAP 8 and DAP 12, respectively) and FOF of 40 mg/kg intravenously every 8 h, alone and in combination, were evaluated against 2 vancomycin-resistantEnterococcus faeciumstrains (8019 and 5938) and 2 vancomycin-resistantE. faecalisstrains (V583 and R7302) in anin vitroPK/PD model over 72 h. Cell surface charge in the presence and absence of FOF was evaluated by zeta potential analysis. Daptomycin-boron-dipyrromethene (bodipy) binding was assessed by fluorescence microscopy. The addition of FOF to DAP 8 and DAP 12 resulted in significantly increased killing over DAP alone at 72 h for 8019, V583, and R7302 (P< 0.05). Therapeutic enhancement was observed with DAP 12 plus FOF against 8019, V583, and R7302. Cell surface charge became more negative after exposure to FOF by ∼2 to 8mV in all 4 strains. Daptomycin-bodipy binding increased by 2.6 times in the presence of fosfomycin (P< 0.0001). The combination of DAP plus FOF may provide improved killing against VRE (including DAP-resistant strains) through modulation of cell surface charge. Further studies to clarify the role of intravenous FOF are warranted.

scholarly journals DaptomycinIn VitroActivity against Methicillin-Resistant Staphylococcus aureus Is Enhanced by d-Cycloserine in a Mechanism Associated with a Decrease in Cell Surface Charge

2013 ◽  
Vol 57 (9) ◽  
pp. 4537-4539 ◽  
Author(s):  
O. Gasch ◽  
S. K. Pillai ◽  
J. Dakos ◽  
S. Miyakis ◽  
R. C. Moellering ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Surface Charge ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Binding Assays ◽  
Methicillin Resistant ◽  
Content Type ◽  
Killing Activity ◽  
Cell Surface Charge ◽  
Mrsa Strains

ABSTRACTThe killing activity of daptomycin against an isogenic pair of daptomycin-susceptible and daptomycin-nonsusceptible (DNS) methicillin-resistantStaphylococcus aureus(MRSA) strains was enhanced by the addition of certain cell wall agents at 1× MIC. However, when high inocula of the DNS strain were used, no significant killing was observed in our experiments. Cytochromecbinding assays revealedd-cycloserine as the only agent associated with a reduction in the cell surface charge for both strains at the concentrations used.

scholarly journals Mapping Surface Charge Distribution of Single-Cell via Charged Nanoparticle

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1519
Author(s):  
Leixin Ouyang ◽  
Rubia Shaik ◽  
Ruiting Xu ◽  
Ge Zhang ◽  
Jiang Zhe
Keyword(s):  
Cell Surface ◽  
Charge Density ◽  
Surface Charge ◽  
Charge Distribution ◽  
Surface Charge Density ◽  
Single Cells ◽  
Fluorescent Light ◽  
Fluorescent Nanoparticles ◽  
Cell Surface Charge ◽  
Surface Charge Distribution

Many bio-functions of cells can be regulated by their surface charge characteristics. Mapping surface charge density in a single cell’s surface is vital to advance the understanding of cell behaviors. This article demonstrates a method of cell surface charge mapping via electrostatic cell–nanoparticle (NP) interactions. Fluorescent nanoparticles (NPs) were used as the marker to investigate single cells’ surface charge distribution. The nanoparticles with opposite charges were electrostatically bonded to the cell surface; a stack of fluorescence distribution on a cell’s surface at a series of vertical distances was imaged and analyzed. By establishing a relationship between fluorescent light intensity and number of nanoparticles, cells’ surface charge distribution was quantified from the fluorescence distribution. Two types of cells, human umbilical vein endothelial cells (HUVECs) and HeLa cells, were tested. From the measured surface charge density of a group of single cells, the average zeta potentials of the two types of cells were obtained, which are in good agreement with the standard electrophoretic light scattering measurement. This method can be used for rapid surface charge mapping of single particles or cells, and can advance cell-surface-charge characterization applications in many biomedical fields.

Bio-fabricated silver nanoparticles preferentially targets Gram positive depending on cell surface charge

2016 ◽  
Vol 83 ◽  
pp. 548-558 ◽  
Author(s):  
Debasis Mandal ◽  
Sandeep Kumar Dash ◽  
Balaram Das ◽  
Sourav Chattopadhyay ◽  
Totan Ghosh ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cell Surface ◽  
Surface Charge ◽  
Gram Positive ◽  
Cell Surface Charge

scholarly journals On the role of metal cations in cellular adhesion: Effect on cell surface charge

1966 ◽  
Vol 163 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Peter B. Armstrong
Keyword(s):  
Cell Surface ◽  
Surface Charge ◽  
Metal Cations ◽  
Cellular Adhesion ◽  
Cell Surface Charge ◽  
Adhesion Effect

Regulation of bacterial abstraction of lead by cell surface charge and chemical equilibria

Chemosphere ◽  
1980 ◽  
Vol 9 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Christopher L. Haber ◽  
Thomas G. Tornabene ◽  
R.K. Skogerboe
Keyword(s):  
Cell Surface ◽  
Surface Charge ◽  
Chemical Equilibria ◽  
Cell Surface Charge

scholarly journals Genomic Analysis of Multiresistant Staphylococcus capitis Associated with Neonatal Sepsis

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Glen P. Carter ◽  
James E. Ussher ◽  
Anders Gonçalves Da Silva ◽  
Sarah L. Baines ◽  
Helen Heffernan ◽  
...  
Keyword(s):  
Neonatal Sepsis ◽  
Neonatal Intensive Care ◽  
Genomic Analysis ◽  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
Comparative Genomic ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Staphylococcus Capitis ◽  
Hospital Infection Control

ABSTRACT Coagulase-negative staphylococci (CoNS), such as Staphylococcus capitis, are major causes of bloodstream infections in neonatal intensive care units (NICUs). Recently, a distinct clone of S. capitis (designated S. capitis NRCS-A) has emerged as an important pathogen in NICUs internationally. Here, 122 S. capitis isolates from New Zealand (NZ) underwent whole-genome sequencing (WGS), and these data were supplemented with publicly available S. capitis sequence reads. Phylogenetic and comparative genomic analyses were performed, as were phenotypic assessments of antimicrobial resistance, biofilm formation, and plasmid segregational stability on representative isolates. A distinct lineage of S. capitis was identified in NZ associated with neonates and the NICU environment. Isolates from this lineage produced increased levels of biofilm, displayed higher levels of tolerance to chlorhexidine, and were multidrug resistant. Although similar to globally circulating NICU-associated S. capitis strains at a core-genome level, NZ NICU S. capitis isolates carried a novel stably maintained multidrug-resistant plasmid that was not present in non-NICU isolates. Neonatal blood culture isolates were indistinguishable from environmental S. capitis isolates found on fomites, such as stethoscopes and neonatal incubators, but were generally distinct from those isolates carried by NICU staff. This work implicates the NICU environment as a potential reservoir for neonatal sepsis caused by S. capitis and highlights the capacity of genomics-based tracking and surveillance to inform future hospital infection control practices aimed at containing the spread of this important neonatal pathogen.

Sub-Microfluidic Setup to Quantify Cell Surface & Charge Density

2019 ◽  
Author(s):  
Oleksii Yu. Borikov ◽  
Oksana M. Morozova ◽  
Volodymyr P. Berest
Keyword(s):  
Cell Surface ◽  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Cell Surface Charge

Effects of Cell Surface Charge and Hydrophobicity on Attachment of 16 Salmonella Serovars to Cantaloupe Rind and Decontamination with Sanitizers†

2006 ◽  
Vol 69 (8) ◽  
pp. 1835-1843 ◽  
Author(s):  
DIKE O. UKUKU ◽  
WILLIAM F. FETT
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Surface ◽  
Surface Charge ◽  
Storage Period ◽  
Bacterial Attachment ◽  
The Other ◽  
Average Percentage ◽  
Log Reduction ◽  
Cell Surface Charge ◽  
Salmonella Serovars

Adherence of bacteria to cantaloupe rind is favored by surface irregularities such as roughness, crevices, and pits, thus reducing the ability of washing or sanitizer treatments to remove or inactivate attached cells. In this study, we compared the surface charge and hydrophobicity of two cantaloupe-related outbreak strains of Salmonella Poona (RM2350 and G-91-1595) to those of 14 additional Salmonella strains using electrostatic and hydrophobic interaction chromatography. The relative abilities of the 16 strains to attach to cantaloupe surfaces and resist removal by washing with water, chlorine (200 ppm), or hydrogen peroxide (2.5%) for 5 min after a storage period of up to 7 days at 5 to 20°C also were determined. Whole cantaloupes were inoculated with each pathogen at 8.36 log CFU/ml, dried for 1 h inside a biosafety cabinet, stored, and then subjected to the washing treatments. Only the positive surface charge of the two cantaloupe-related strains of Salmonella Poona was significantly higher (P &lt; 0.05) than that of the other strains. Initial bacterial attachment to cantaloupe surfaces ranged from 3.68 to 4.56 log CFU/cm2 (highest values for Salmonella Michigan, Newport, Oranienburg, and Mbandaka). The average percentage of the total bacterial population strongly attached to the cantaloupe surface for the Salmonella serovars studied ranged from 0.893 to 0.946 at 5°C and from 0.987 to 0.999 at 25°C. Washing inoculated melons with water did not produce a significant reduction in the concentration of the pathogens (P &gt; 0.05). Chlorine and hydrogen peroxide treatments caused an average 3-log reduction when applied 20 to 40 min postinoculation. However, sanitizer treatments applied 60 min or more postinoculation were less effective (approximately 2.5-log reduction). No significant differences were noted in sanitizer efficacy against the individual strains (P &gt; 0.05). The two cantaloupe-related outbreak Salmonella Poona strains did not significantly differ from the other Salmonella strains tested in negative cell surface charge or hydrophobicity, were not more effective in attaching to whole melon surfaces, and were not more resistant to the various washing treatments when present on rinds.

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