scholarly journals Lipoteichoic Acid Biosynthesis Inhibitors as Potent Inhibitors of S. aureus and E. faecalis Growth and Biofilm Formation

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2277
Author(s):  
George A. Naclerio ◽  
Kenneth I. Onyedibe ◽  
Herman O. Sintim
Keyword(s):  
Biofilm Formation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Lipoteichoic Acid ◽  
Acid Biosynthesis ◽  
Biofilm Inhibition ◽  
Teichoic Acids ◽  
Biosynthesis Inhibitors ◽  
New Chemical Entities ◽  
Vancomycin Resistant ◽  
Wall Teichoic Acids

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE) have been deemed as serious threats by the CDC. Many chronic MRSA and VRE infections are due to biofilm formation. Biofilm are considered to be between 10–10,000 times more resistant to antibiotics, and therefore new chemical entities that inhibit and/or eradicate biofilm formation are needed. Teichoic acids, such as lipoteichoic acids (LTAs) and wall teichoic acids (WTAs), play pivotal roles in Gram-positive bacteria’s ability to grow, replicate, and form biofilms, making the inhibition of these teichoic acids a promising approach to fight infections by biofilm forming bacteria. Here, we describe the potent biofilm inhibition activity against MRSA and VRE biofilms by two LTA biosynthesis inhibitors HSGN-94 and HSGN-189 with MBICs as low as 0.0625 µg/mL against MRSA biofilms and 0.5 µg/mL against VRE biofilms. Additionally, both HSGN-94 and HSGN-189 were shown to potently synergize with the WTA inhibitor Tunicamycin in inhibiting MRSA and VRE biofilm formation.

scholarly journals Bisdemethoxycurcumin Reduces Methicillin-Resistant Staphylococcus aureus Expression of Virulence-Related Exoproteins and Inhibits the Biofilm Formation

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 804
Author(s):  
Shu Wang ◽  
Ok-Hwa Kang ◽  
Dong-Yeul Kwon
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Mrna Level ◽  
Accessory Gene ◽  
Biofilm Inhibition ◽  
Methicillin Resistant ◽  
Accessory Gene Regulator ◽  
Release Assay ◽  
Necrosis Factor

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen of nosocomial infection, which is resistant to most antibiotics. Presently, anti-virulence therapy and anti-biofilm therapy are considered to be promising alternatives. In the current work, we investigated the influence of bisdemethoxycurcumin (BDMC) on the virulence-related exoproteins and the biofilm formation using a reference strain and clinic isolated strains. Western blotting, quantitative RT-PCR, and tumor necrosis factor (TNF) release assay were performed to assess the efficacy of BDMC in reducing the expression of Staphylococcus enterotoxin-related exoproteins (enterotoxin A, enterotoxin B) and α-toxin in MRSA. The anti-biofilm activity of BDMC was evaluated through a biofilm inhibition assay. The study suggests that sub-inhibitory concentrations of BDMC significantly inhibited the expression of sea, seb, and hla at the mRNA level in MRSA. Moreover, the expression of virulence-related exoproteins was significantly decreased by down-regulating accessory gene regulator agr, and the inhibition of biofilms formation was demonstrated by BDMC at sub-inhibitory concentrations. Consequently, the study suggests that BDMC may be a potential natural antibacterial agent to release the pressure brought by antibiotic resistance.

Wall teichoic acids: Physiology and applications

2020 ◽  
Author(s):  
Xia Wu ◽  
Jing Han ◽  
Guoli Gong ◽  
Mattheos A G Koffas ◽  
Jian Zha
Keyword(s):  
Biofilm Formation ◽  
Mammalian Cells ◽  
Cell Envelope ◽  
Cell Metabolism ◽  
Cell Interaction ◽  
Antibacterial Drug ◽  
Human Society ◽  
Surface Adhesion ◽  
Teichoic Acids ◽  
Wall Teichoic Acids

Abstract Wall teichoic acids (WTAs) are charged glycopolymers containing phosphodiester-linked polyol units and represent one of the major components of Gram-positive cell envelope. WTAs have important physiological functions in cell division, gene transfer, surface adhesion, drug resistance, and biofilm formation, and are critical virulence factors and vital determinants in mediating cell interaction with and tolerance to environmental factors. Here we first briefly introduce WTA structure, biosynthesis and its regulation, and then summarize in detail four major physiological roles played by WTAs, i.e. WTA-mediated resistance to antimicrobials, virulence to mammalian cells, interaction with bacteriolytic enzymes, and regulation of cell metabolism. We also review the applications of WTAs in these fields that are closely related to the human society, including antibacterial drug discovery targeting WTA biosynthesis, development of vaccines and antibodies regarding WTA-mediated pathogenicity, specific and sensitive detection of pathogens in food using WTAs as a surface epitope, and regulation of WTA-related pathways for efficient microbial production of useful compounds. We also point out major problems remaining in these fields, and discuss some possible directions in the future exploration of WTA physiology and applications.

scholarly journals Synthesis, Anti-Bacterial and Anti-biofilm Activity of New Iminothiazolidinones

2021 ◽  
pp. 33-40
Author(s):  
Kumaraswamy Gullapelli ◽  
Ravichander Maroju
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Simple Procedure ◽  
Chloroacetic Acid ◽  
Bacterial Strains ◽  
Reaction Conditions ◽  
Biofilm Inhibition ◽  
Wide Range ◽  
Potential Activity ◽  
Vancomycin Resistant ◽  
Pharmaceutical Properties

Aim: Iminothiazolidinones are one of the important classes of heterocyclic compounds and they occupied unique position in medicinal chemistry due to their wide range of biological and pharmaceutical properties. In view this potential activity, it has been planned to synthesize a series of New Iminothiazolidinones on benzimidazole nucleus and to study their biological activity. Methodology: Iminothiazolidinones and 1,1 dioxide- Iminothiazolidinones were synthesized with a simple and efficient method of cyclic condensation of aryl thiourea containing benzimidazole and thiazole with chloroacetic acid .This method requires mild reaction conditions, simple procedure and gives good yield. Results: The structures of the synthesized compounds were assessed by Infrared, NMR and Mass spectroscopic methods. The synthesized compounds were screened for their antibacterial and biofilm inhibitory activities against selected multi drug resistant bacterial strains. Conclusion: In accordance with the results obtained, growth inhibition was found significant with compounds 5d and 5e. Methicillin resistant Staphylococcus aureus (MRSA), Vancomycin resistant Enterococcus (VRE), and extended spectrum β‑lactamase (ESBL) producing Klebsiella pneumoniae have shown varied susceptibility towards these compounds. The Biofilm inhibition Concentrations (BFIC) of compounds 5e and 5d are 3.22 ±0.56 and 6.58 ±1.5 µg/mL respectively were noted against MRSA.

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

scholarly journals Biofilm inhibition and bactericidal activity of NiTi alloy coated with graphene oxide/silver nanoparticles via electrophoretic deposition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sirapat Pipattanachat ◽  
Jiaqian Qin ◽  
Dinesh Rokaya ◽  
Panida Thanyasrisung ◽  
Viritpon Srimaneepong
Keyword(s):  
Surface Roughness ◽  
Silver Nanoparticles ◽  
Graphene Oxide ◽  
Electrophoretic Deposition ◽  
Biofilm Formation ◽  
Niti Alloy ◽  
Surface Characteristics ◽  
Dependent Manner ◽  
Biofilm Inhibition ◽  
Coating Time

AbstractBiofilm formation on medical devices can induce complications. Graphene oxide/silver nanoparticles (GO/AgNPs) coated nickel-titanium (NiTi) alloy has been successfully produced. Therefore, the aim of this study was to determine the anti-bacterial and anti-biofilm effects of a GO/AgNPs coated NiTi alloy prepared by Electrophoretic deposition (EPD). GO/AgNPs were coated on NiTi alloy using various coating times. The surface characteristics of the coated NiTi alloy substrates were investigated and its anti-biofilm and anti-bacterial effect on Streptococcus mutans biofilm were determined by measuring the biofilm mass and the number of viable cells using a crystal violet assay and colony counting assay, respectively. The results showed that although the surface roughness increased in a coating time-dependent manner, there was no positive correlation between the surface roughness and the total biofilm mass. However, increased GO/AgNPs deposition produced by the increased coating time significantly reduced the number of viable bacteria in the biofilm (p < 0.05). Therefore, the GO/AgNPs on NiTi alloy have an antibacterial effect on the S. mutans biofilm. However, the increased surface roughness does not influence total biofilm mass formation (p = 0.993). Modifying the NiTi alloy surface using GO/AgNPs can be a promising coating to reduce the consequences of biofilm formation.

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