{"content"=>"A Novel Antimicrobial Coating Represses Biofilm and Virulence-Related Genes in Methicillin-Resistant.", "i"=>{"content"=>"Staphylococcus aureus"}} (original) (raw)
Related papers
Frontiers in Bioengineering and Biotechnology, 2020
Emerging antibiotic-resistant bacteria result in increased mortality and have negative economic impacts. It is necessary to discover new strategies to create alternative antibacterial agents that suppress the bacterial resistance mechanism and limit the spread of serious infectious bacterial diseases. Silver nanoparticles may represent a new medicinal agents as alternative antibiotics affect different bacterial mechanisms such as virulence and resistance. In addition to that of silver nitrate (AgNO 3) and ampicillin, for the first time, the inhibitory effect of silver nanoparticles synthesized using Desertifilum sp. (D-SNPs) was evaluated against five pathogenic bacteria using the agar well diffusion method. Also, the influence of D-SNPs and AgNO 3 on bacterial antioxidant and metabolic activities was studied. The antibacterial activity of D-SNPs and AgNO 3 against methicillin-resistant Staphylococcus aureus (MRSA) strains was studied at the morphological and molecular level. D-SNPs and AgNO 3 have the ability to inhibit the growth of the five bacterial strains and resulted in an imbalance in the CAT, GSH, GPx and ATPase levels. MRSA treated with D-SNPs and AgNO 3 showed different morphological changes such as apoptotic bodies formation and cell wall damage. Moreover, both caused genotoxicity and denaturation of MRSA cellular proteins. Additionally, TEM micrographs showed the distribution of SNPs synthesized by MRSA. This result shows the ability of MRSA to reduce silver nitrate into silver nanoparticles. These data indicate that D-SNPs may be a significant alternative antibacterial agent against different bacteria, especially MDR bacteria, by targeting the virulence mechanism and biofilm formation, leading to bacterial death.
Novel silver metformin nano-structure to impede virulence of Staphylococcus aureus
AMB Express
Staphylococcus aureus is a prevalent etiological agent of health care associated and community acquired infections. Antibiotic abuse resulted in developing multidrug resistance in S. aureus that complicates treatment of infections. Targeting bacterial virulence using FDA approved medication offers an alternative to the antibiotics with no stress on bacterial viability. Using nanomaterials as anti-virulence agent against S. aureus virulence factors is a valuable approach. This study aims to investigate the impact of metformin (MET), metformin nano (MET-Nano), silver metformin nano structure (Ag-MET-Ns) and silver nanoparticles (AgNPs) on S. aureus virulence and pathogenicity. The in vitro results showed a higher inhibitory activity against S. aureus virulence factors with both MET-Nano and Ag-MET-Ns treatment. However, genotypically, it was found that except for agrA and icaR genes that are upregulated, the tested agents significantly downregulated the expression of crtM, sigB, sarA ...
Antibiotics
The urgent need to combat antibiotic resistance and develop novel antimicrobial therapies has triggered studies on novel metal-based formulations. N-heterocyclic carbene (NHC) complexes coordinate transition metals to generate a broad range of anticancer and/or antimicrobial agents, with ongoing efforts being made to enhance the lipophilicity and drug stability. The lead silver(I) acetate complex, 1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene (NHC*) (SBC3), has previously demonstrated promising growth and biofilm-inhibiting properties. In this work, the responses of two structurally different bacteria to SBC3 using label-free quantitative proteomics were characterised. Multidrug-resistant Pseudomonas aeruginosa (Gram-negative) and Staphylococcus aureus (Gram-positive) are associated with cystic fibrosis lung colonisation and chronic wound infections, respectively. SBC3 increased the abundance of alginate biosynthesis, the secretion system and drug detoxification proteins in P. aerugin...
Journal of Microbiology and Biotechnology
Staphylococcus aureus causes diseases ranging from fairly minor skin and soft-tissue infections to dangerous sepsis [1, 2]. All penicillins are ineffective against MRSA, including cephalosporins, carbapenems, semi-synthetic penicillinase-resistant congeners, and penems. Once methicillin was discovered in 1960, resistant strains were named after the showing of clinical isolates in England by 1967. MRSA was described in several countries primarily in the early 1980s. MDR-MRSA has been reported in numerous countries and is presently endemic in many hospitals worldwide, and commonly in developing countries such as Brazil [3]. Because of the increased mortality related to MRSA infections, the emergence of strains resistant to methicillin and other antimicrobials has become a major concern, particularly in the hospital context [2]. Between 1999 and 2002, increases in methicillin resistance were found in S. aureus isolates in European nations, namely Belgium, Germany, Ireland, the Netherlands, and the United Kingdom. In Northern, Western, and Southern Europe, MRSA incidence ranged from 1% to 40%, respectively [4]. The need to halt the spread of MRSA and decrease the incidence of MRSA infections in hospital settings now appears critical, as the multidrug-resistant organism's prevalence persists. According to a recent study, the average MRSA transporter ratio among healthcare workers is 4.6%, with 5.1% having typical MRSA infections. MRSA levels must also be controlled by healthcare staff [2]. Staphylococcus aureus is a cause of high mortality in humans and therefore it is necessary to prevent its transmission and reduce infections. Our goals in this research were to investigate the frequency of methicillin-resistant S. aureus (MRSA) in Taif, Saudi Arabia, and assess the relationship between the phenotypic antimicrobial sensitivity patterns and the genes responsible for resistance. In addition, we examined the antimicrobial efficiency and application of silver nanoparticles (AgNPs) against MRSA isolates. Seventy-two nasal swabs were taken from patients; MRSA was cultivated on Mannitol Salt Agar supplemented with methicillin, and 16S rRNA sequencing was conducted in addition to morphological and biochemical identification. Specific resistance genes such as ermAC, aacA-aphD, tetKM, vatABC and mecA were PCR-amplified and resistance plasmids were also investigated. The MRSA incidence was ~49 % among the 72 S. aureus isolates and all MRSA strains were resistant to oxacillin, penicillin, and cefoxitin. However, vancomycin, linezolid, teicoplanin, mupirocin, and rifampicin were effective against 100% of MRSA strains. About 61% of MRSA strains exhibited multidrug resistance and were resistant to 3-12 antimicrobial medications (MDR). Methicillin resistance gene mecA was presented in all MDR-MRSA strains. Most MDR-MRSA contained a plasmid of > 10 kb. To overcome bacterial resistance, AgNPs were applied and displayed high antimicrobial activity and synergistic effect with penicillin. Our findings may help establish programs to control bacterial spread in communities as AgNPs appeared to exert a synergistic effect with penicillin to control bacterial resistance.
Synergistic Antimicrobial Effects of Silver/Transition-metal Combinatorial Treatments
Scientific Reports, 2017
Due to the emergence of multi-drug resistant strains, development of novel antibiotics has become a critical issue. One promising approach is the use of transition metals, since they exhibit rapid and significant toxicity, at low concentrations, in prokaryotic cells. Nevertheless, one main drawback of transition metals is their toxicity in eukaryotic cells. Here, we show that the barriers to use them as therapeutic agents could be mitigated by combining them with silver. We demonstrate that synergism of combinatorial treatments (Silver/transition metals, including Zn, Co, Cd, Ni, and Cu) increases up to 8-fold their antimicrobial effect, when compared to their individual effects, against E. coli and B. subtilis. We find that most combinatorial treatments exhibit synergistic antimicrobial effects at low/ non-toxic concentrations to human keratinocyte cells, blast and melanoma rat cell lines. Moreover, we show that silver/(Cu, Ni, and Zn) increase prokaryotic cell permeability at sub-inhibitory concentrations, demonstrating this to be a possible mechanism of the synergistic behavior. Together, these results suggest that these combinatorial treatments will play an important role in the future development of antimicrobial agents and treatments against infections. In specific, the cytotoxicity experiments show that the combinations have great potential in the treatment of topical infections. In the past three decades, global usage of antibiotics has become disproportionate, and, in the majority of instances, unsuitable 1. This has led to the emergence of multi-drug resistant strains. Highly resistant Gram-negative bacteria, such as P. aeruginosa, Acinetobacter, Klebsiella and Escherichia species, have become worldwide relevant pathogens 2 and are part of the ESKAPE list which includes the most current deadly pathogens 3. In addition, some Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus 1, 4, 5 , and vancomycin-resistant Streptococcus pneumonia 4 , are pathogens also very difficult to treat. The spreading of antibiotic-resistant strains embodies an issue in which international health institutions spend millions of dollars annually 5. As a result, increasingly significant attention has been paid to the development of novel antibiotics;
International Research Journal Of Pharmacy
Nanotechnology is emerging as a new interdisciplinary field combining microbiology, Chemistry, physics, and material science. Recent advances promise developments in the synthesis, modification and practical applications of nanoparticles (NPs). Nanoparticles were excellent antibacterial agents with potential clinical applications. Sliver Nanoparticles have been successfully used in a wide range of applications including wound dressing, protective clothing, antibacterial surfaces, food preservation, and cosmetics as biocidal and disinfecting agents. The aim of this study was to investigate the mechanism of silver nanoparticle action against of methicillin-resistant Staphylococcus aureus. The Gram-positive methicillin-resistant Staphylococcus areas were used to evaluate the antibacterial activities of silver nanoparticles (Ag NPs). The growth rate of methicillin-resistant Staphylococcus aureus was investigated under varying Ag NPs concentrations by scanning electron microscope (SEM) & acridine orange /ethidium bromide (AO-EtBr) staining. The Quantitative Real-time PCR experiment showed that the mecA gene from the bacterial cells treated with Ag-NPs was downregulated compared to that in the untreated cells.
2020
Background & Aims: The increasing rate of vancomycin resistant Staphylococcus aureus (VRSA) with biofilm formation may become a new threat to humans. In such cases, finding an effective treatment strategy such as using Nanotechnology (Nanodrugs) to deal with these types of infections may be promising. This study aimed to investigate the inhibitory effects of silver nanoparticles (SNPs) on biofilm formation of VRSAs. Materials and Methods: Clinical S. aureus isolates were identified to the species level by conventional methods, and their identities were later confirmed by PCR. Following the determination of susceptibility patterns of the isolates; all the screened S.aureus isolates have been assessed regarding their susceptibility to vancomycin. Detection of vanA gene and determination of minimum inhibitory concentrations (MICs) of VRSAs were carried out using PCR and Etest methods, respectively. The biofilm production was assessed on all VRSA isolates in the presence/absence of SNPs...
New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens
Materials Science and Engineering: C, 2015
Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited growth of the nosocomial pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells.
Antibiotics
Antibiotics are regarded as a miracle in the medical field as it prevents disease caused by pathogenic bacteria. Since the discovery of penicillin, antibiotics have become the foundation for modern medical discoveries. However, bacteria soon became resistant to antibiotics, which puts a burden on the healthcare system. Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most prominent antibiotic-resistant bacteria in the world since 1961. MRSA primarily developed resistance to beta-lactamases antibiotics and can be easily spread in the healthcare system. Thus, alternatives to combat MRSA are urgently required. Antimicrobial peptides (AMPs), an innate host immune agent and silver nanoparticles (AgNPs), are gaining interest as alternative treatments against MRSA. Both agents have broad-spectrum properties which are suitable candidates for controlling MRSA. Although both agents can exhibit antimicrobial effects independently, the combination of both can be synergis...