Antimicrobial Synergic Effect of Allicin and Silver Nanoparticles on Skin Infection Caused by Methicillin-Resistant Staphylococcus aureus spp

Nanosilver: An Old Antibacterial Agent with Great Promise in the Fight against Antibiotic Resistance

Antibiotic resistance in bacteria is a major problem worldwide that costs 55 billion USD annually for extended hospitalization, resource utilization, and additional treatment expenditures in the United States. This review examines the roles and forms of silver (e.g., bulk Ag, silver salts (AgNO3), and colloidal Ag) from antiquity to the present, and its eventual incorporation as silver nanoparticles (AgNPs) in numerous antibacterial consumer products and biomedical applications. The AgNP fabrication methods, physicochemical properties, and antibacterial mechanisms in Gram-positive and Gram-negative bacterial models are covered. The emphasis is on the problematic ESKAPE pathogens and the antibiotic-resistant pathogens of the greatest human health concern according to the World Health Organization. This review delineates the differences between each bacterial model, the role of the physicochemical properties of AgNPs in the interaction with pathogens, and the subsequent damage of AgNPs and Ag+ released by AgNPs on structural cellular components. In closing, the processes of antibiotic resistance attainment and how novel AgNP-antibiotic conjugates may synergistically reduce the growth of antibiotic-resistant pathogens are presented in light of promising examples, where antibiotic efficacy alone is decreased.

Facile Synthesis, Characterization, and Antimicrobial Assessment of a Silver/Montmorillonite Nanocomposite as an Effective Antiseptic against Foodborne Pathogens for Promising Food Protection

Foodborne pathogens can have devastating repercussions and significantly threaten public health. Therefore, it is indeed essential to guarantee the sustainability of our food production. Food preservation and storage using nanocomposites is a promising strategy. Accordingly, the present research's objectives were to identify and isolate a few foodborne pathogens from food products, (ii) synthesize and characterize silver nanoparticles (AgNPs) using wet chemical reduction into the lamellar space layer of montmorillonite (MMT), and (iii) investigate the antibacterial potential of the AgNPs/MMT nanocomposite versus isolated strains of bacteria. Six bacterial species, including Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus were isolated from some food products (meat, fish, cheese, and vegetables). The Ag/MMT nanocomposite was synthesized and characterized using UV-visible spectroscopy, transmission electron microscopy, particle size analyzer, zeta potential, X-ray diffraction (XRD), and scanning electron microscopy with dispersive energy X-ray (EDX). The antibacterial effectiveness of the AgNPs/MMT nanocomposite further investigated distinct bacterial species using a zone of inhibition assay and microtiter-based methods. Nanoparticles with a narrow dimension range of 12 to 30 nm were identified using TEM analysis. The SEM was employed to view the sizeable flakes of the AgNPs/MMT. At 416 nm, the most excellent UV absorption was measured. Four silver metallic diffraction peaks were found in the XRD pattern during the study, and the EDX spectrum revealed a strong signal attributed to Ag nanocrystals. AgNPs/MMT figured out the powerful antibacterial action. The AgNPs/MMT nanocomposite confirmed outstanding minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against six isolates of foodborne pathogens, ranging from 15 to 75 µg/mL, respectively. The AgNPs/MMT's antibacterial potential against gram-negative bacteria was noticeably better than gram-positive bacteria. Therefore, the AgNPs/MMT nanocomposite has the potential to be used as a reliable deactivator in food processing and preservation to protect against foodborne pathogenic bacteria. This suggests that the nanocomposite may be effective at inhibiting the growth and proliferation of harmful bacteria in food, which could help to reduce the risk of foodborne illness.

Nanomedicine: New Frontiers in Fighting Microbial Infections

Microbes have dominated life on Earth for the past two billion years, despite facing a variety of obstacles. In the 20th century, antibiotics and immunizations brought about these changes. Since then, microorganisms have acquired resistance, and various infectious diseases have been able to avoid being treated with traditionally developed vaccines. Antibiotic resistance and pathogenicity have surpassed antibiotic discovery in terms of importance over the course of the past few decades. These shifts have resulted in tremendous economic and health repercussions across the board for all socioeconomic levels; thus, we require ground-breaking innovations to effectively manage microbial infections and to provide long-term solutions. The pharmaceutical and biotechnology sectors have been radically altered as a result of nanomedicine, and this trend is now spreading to the antibacterial research community. Here, we examine the role that nanomedicine plays in the prevention of microbial infections, including topics such as diagnosis, antimicrobial therapy, pharmaceutical administration, and immunizations, as well as the opportunities and challenges that lie ahead.

Biological Synthesis of Silver Nanoparticles by Amaryllis vittata (L.) Herit: From Antimicrobial to Biomedical Applications

The current study sought to synthesize silver nanoparticles (AgNPs) from Amaryllis vittata (L.) leaf and bulb extracts in order to determine their biological significance and use the toxic plants for human health benefits. The formation of silver nanoparticles was detected by a change in color from whitish to brown for bulb-AgNPs and from light green to dark brown for leaf-AgNPs. For the optimization of silver nanoparticles, various experimental physicochemical parameters such as pH, temperature, and salt were determined. UV-vis spectroscopy, Fourier transform infrared spectroscopy, X-ray dispersion spectroscopy, scanning electron microscopy, and energy dispersion spectroscopy analysis were used to characterize nanoparticles. Despite the fact that flavonoids in plant extracts were implicated in the reduction and capping procedure, the prepared nanoparticles demonstrated maximum absorbency between 400 and 500 nm. SEM analysis confirmed the preparation of monodispersed spherical crystalline particles with fcc structure. The bioinspired nanoparticles were found to show effective insecticidal activity against Tribolium castaneum and phytotoxic activity against Lemna aequincotialis. In comparison to plant extracts alone, the tested fabricated nanoparticles showed significant potential to scavenge free radicals and relieve pain. Antibacterial testing against human pathogenic strains, i.e., Escherichia coli and Pseudomonas aureginosa, and antifungal testing against Aspergillus niger revealed the significant potential for microbe resistance using AgNPs. As a result of the findings, the tested silver nanoparticles demonstrated promising potential for developing new and effective pharmacological and agricultural medications. Furthermore, the effects of biogenic AgNPs on an in vitro culture of Solanum tuberosum L. plants were investigated, and the findings indicated that bulb-AgNPs and leaf-AgNPs produced biomass and induced antioxidants via their active constituents. As a result, bulb-AgNPs and leaf-AgNPs may be recommended for use in Solanum tuberosum L. tissue culture for biomass fabrication and metabolic induction.

Evaluation of Antibacterial and Antibiofilm Activity of Biogenic Silver Nanoparticles and Gentamicin Against Staphylococcus aureus Isolated from Caprine Mastitis

The goal of this study was to assess the antibacterial efficiency of biogenic silver nanoparticles (AgNPs) and gentamicin against Staphylococcus aureus that can form biofilms. The characterization of AgNPs‎ was confirmed by the scanning electron microscope (SEM) which was spherical and homogenous in form, with a diameter between 25 and 45 nm. The X-ray diffraction (XRD) presented the size of AgNPs to be 50 nm. Energy dispersive spectroscopy (EDS) was used to examine the presence of elemental silver. The three-dimensional structure of silver nanoparticles was discovered using an atomic force microscope (AFM), with a diameter of 47.18 nm on average. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of AgNPs and gentamicin against S. aureus isolated from caprine mastitis were determined using the microdilution assay. The checkerboard microdilution technique was utilized to inspect the synergistic antibacterial activity of AgNPs with gentamicin utilizing the fractional inhibitory concentration index (FICI). The antibiofilm capability of AgNPs was also investigated. The results indicate that AgNPs generated by biosynthesis are antibacterial against S. aureus. Moreover, AgNPs and gentamicin exhibit synergistic action. The study's findings suggest that biogenic AgNPs may act as anti-biofilm agents and treat mastitis caused by S. aureus. In conclusions biosynthesized AgNPs exhibit strong antibacterial and antibiofilm effectiveness and synergistic activity when combined with gentamicin.

Current studies and potential future research directions on biological effects and related mechanisms of allicin

Allicin, a thiosulfonate extract from freshly minced garlic, has been reported to have various biological effects on different organs and systems of animals and human. It can reduce oxidative stress, inhibit inflammatory response, resist pathogen infection and regulate intestinal flora. In addition, dozens of studies also demonstrated allicin could reduce blood glucose level, protect cardiovascular system and nervous system, and fight against cancers. Allicin was widely used in disease prevention and health care. However, more investigations on human cohort study are needed to verify the biological or clinical effects of allicin in the future. In this review, we summarized the biological effects of allicin from previous outstanding and valuable studies and provided useful information for future studies on the health effects of allicin.

Garlic-derived organosulfur compounds regulate metabolic and immune pathways in macrophages and attenuate intestinal inflammation in mice

Scope: Garlic is a source of bioactive phytonutrients that may have anti‐inflammatory or immunomodulatory properties. The mechanism(s) underlying the bioactivity of these compounds and their ability to regulate responses to enteric infections remains unclear.

Methods and Results: This study investigates if a garlic‐derived preparation (PTSO‐PTS) containing two organosulfur metabolites, propyl‐propane thiosulfonate (PTSO), and propyl‐propane thiosulfinate (PTS), regulate inflammatory responses in murine macrophages and intestinal epithelial cells (IEC) in vitro, as well as in a model of enteric parasite‐induced inflammation. PTSO‐PTS decreases lipopolysaccharide‐induced secretion of TNFα, IL‐6, and IL‐27 in macrophages. RNA‐sequencing demonstrates that PTSO‐PTS strongly suppresses pathways related to immune and inflammatory signaling. PTSO‐PTS induces the expression of a number of genes involved in antioxidant responses in IEC during exposure to antigens from the parasite Trichuris muris. In vivo, PTSO‐PTS does not affect T. muris establishment or intestinal T‐cell responses but significantly alters cecal transcriptomic responses. Notably, a reduction in T. muris‐induced expression of Tnf, Saa2, and Nos2 is observed.

Conclusion: Garlic‐derived organosulfur compounds exert anti‐inflammatory effects in macrophages and IEC, and regulate gene expression during intestinal infection. These compounds and related organic molecules may thus hold potential as functional food components to improve gut health in humans and animals.

Hyaluronic Acid-Silver Nanocomposites and Their Biomedical Applications: A Review

For the last years scientific community has witnessed a rapid development of novel types of biomaterials, which properties made them applicable in numerous fields of medicine. Although nanosilver, well-known for its antimicrobial, anti-angiogenic, anti-inflammatory and anticancer activities, as well as hyaluronic acid, a natural polysaccharide playing a vital role in the modulation of tissue repair, signal transduction, angiogenesis, cell motility and cancer metastasis, are both thoroughly described in the literature, their complexes are still a novel topic. In this review we introduce the most recent research about the synthesis, properties, and potential applications of HA-nanosilver composites. We also make an attempt to explain the variety of mechanisms involved in their action. Finally, we present biocompatible and biodegradable complexes with bactericidal activity and low cytotoxicity, which properties suggest their suitability for the prophylaxis and therapy of chronic wounds, as well as analgetic therapies, anticancer strategies and the detection of chemical substances and malignant cells. Cited studies reveal that the usage of hyaluronic acid-silver nanocomposites appears to be efficient and safe in clinical practice.

Overcoming Multidrug Resistance in Bacteria Through Antibiotics Delivery in Surface-Engineered Nano-Cargos: Recent Developments for Future Nano-Antibiotics

In the recent few decades, the increase in multidrug-resistant (MDR) bacteria has reached an alarming rate and caused serious health problems. The incidence of infections due to MDR bacteria has been accompanied by morbidity and mortality; therefore, tackling bacterial resistance has become an urgent and unmet challenge to be properly addressed. The field of nanomedicine has the potential to design and develop efficient antimicrobials for MDR bacteria using its innovative and alternative approaches. The uniquely constructed nano-sized antimicrobials have a predominance over traditional antibiotics because their small size helps them in better interaction with bacterial cells. Moreover, surface engineering of nanocarriers offers significant advantages of targeting and modulating various resistance mechanisms, thus owe superior qualities for overcoming bacterial resistance. This review covers different mechanisms of antibiotic resistance, application of nanocarrier systems in drug delivery, functionalization of nanocarriers, application of functionalized nanocarriers for overcoming bacterial resistance, possible limitations of nanocarrier-based approach for antibacterial delivery, and future of surface-functionalized antimicrobial delivery systems.

Chemical composition of Callistemon citrinus (Curtis) Skeels aerial part essential oil and its pharmacological applications, neurodegenerative inhibitory, and genotoxic efficiencies

Callistemon citrinus aerial part essential oil (CCEO) was analyzed for chemical compositions using GC/MS. Pharmacological activities such as neurodegenerative inhibitory, antioxidant, anti-inflammatory, antimicrobial, and acetylcholinesterase activities were evaluated using the standard methodologies. Genotoxicity was investigated using Allium cepa assay. GC/MS analysis identified 27 compounds; eucalyptol (55.40%) was the major component. Radical scavenging activity showed IC₅₀ value of 16.71 μg/mL. Protein denaturation assay showed IC₅₀ value of 21.19 μg/mL and 19.53μg/mL in protease inhibitor activity. MIC assay revealed antimicrobial potential of CCEO against microbial strains B. cereus at 2.00 mg/mL, S. typhimurium at 4.50 mg/mL, S. mutans at 2.50 mg/mL, C. albicans at 4.00 mg/mL, and S. cerevisiae at 4.50 mg/mL concentrations. Mitotic index value (MI) of CCEO showed negligible genotoxicity with MI 17.25% close to distilled water 18.22%. Acetylcholinesterase strong inhibitory activity of CCEO was observed from IC₅₀  = 6.335 μg/mL. CCEO could be a cheap and easy source for the extraction of the pure compound eucalyptol and possess various biological activities which increase its pharmacological value as well as its applicability in the field of flavor and fragrance industries. PRACTICAL APPLICATIONS: Eucalyptol is the major component of many pharmaceutical and food/flavor industries. The present investigation provides a new source for the isolation of pure compound eucalyptol in cost-effective way. Additionally, the essential oil could also be used for the pharmaceutical formulation of antioxidant, inflammation inhibitory, and neurodegenerative inhibitory drug preparation under the safety range concentration.

Green synthesized Silver Nanoparticles as Silver Lining in Antimicrobial Resistance: A Review

Unprincipled use of antibiotics has led to the antimicrobial resistance (AMR) against mostly available compounds and now become a major cause of concern for the scientific community. However, in the past decade, green synthesized silver nanoparticles (AgNPs) have received greater attention for the development of newer therapies as antimicrobials by virtue of their unique physico-chemical properties. Unlike traditional antibiotics, AgNPs exert their action by acting on multiple mechanisms which make them potential candidates against AMR. Green synthesis of AgNPs using various medicinal plants has demonstrated broader spectrum of action against several microbes in a number of attempts. The present paper provides an insight into the scientific studies that have elucidated the positive role of plant extracts/phytochemicals during green synthesis of AgNPs and their future perspectives. The studies conducted so far seem promising still, a few factors like, the precise mechanism of action of AgNPs, their synergistic interaction with biomolecules, and industrial scalability need to be explored further till effective drug development using green synthesized AgNPs in healthcare systems against AMR is established.

Amino acid-derived defense metabolites from plants: A potential source to facilitate novel antimicrobial development

For millennia, humanity has relied on plants for its medicines, and modern pharmacology continues to reexamine and mine plant metabolites for novel compounds and to guide improvements in biological activity, bioavailability, and chemical stability. The critical problem of antibiotic resistance and increasing exposure to viral and parasitic diseases has spurred renewed interest into drug treatments for infectious diseases. In this context, an urgent revival of natural product discovery is globally underway with special attention directed toward the numerous and chemically diverse plant defensive compounds such as phytoalexins and phytoanticipins that combat herbivores, microbial pathogens, or competing plants. Moreover, advancements in “omics,” chemistry, and heterologous expression systems have facilitated the purification and characterization of plant metabolites and the identification of possible therapeutic targets. In this review, we describe several important amino acid–derived classes of plant defensive compounds, including antimicrobial peptides (e.g., defensins, thionins, and knottins), alkaloids, nonproteogenic amino acids, and phenylpropanoids as potential drug leads, examining their mechanisms of action, therapeutic targets, and structure–function relationships. Given their potent antibacterial, antifungal, antiparasitic, and antiviral properties, which can be superior to existing drugs, phytoalexins and phytoanticipins are an excellent resource to facilitate the rational design and development of antimicrobial drugs.

Nano-Based Drug Delivery or Targeting to Eradicate Bacteria for Infection Mitigation: A Review of Recent Advances

Pathogenic bacteria infection is a major public health problem due to the high morbidity and mortality rates, as well as the increased expenditure on patient management. Although there are several options for antimicrobial therapy, their efficacy is limited because of the occurrence of drug-resistant bacteria. Many conventional antibiotics have failed to show significant amelioration in overall survival of infectious patients. Nanomedicine for delivering antibiotics provides an opportunity to improve the efficiency of the antibacterial regimen. Nanosystems used for antibiotic delivery and targeting to infection sites render some benefits over conventional formulations, including increased solubility, enhanced stability, improved epithelium permeability and bioavailability, prolonged antibiotic half-life, tissue targeting, and minimal adverse effects. The nanocarriers' sophisticated material engineering tailors the controllable physicochemical properties of the nanoparticles for bacterial targeting through passive or active targeting. In this review, we highlight the recent progress on the development of antibacterial nanoparticles loaded with antibiotics. We systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for bacterial eradication. Passive targeting by modulating the nanoparticle structure and the physicochemical properties is an option for efficient drug delivery to the bacteria. In addition, active targeting, such as magnetic hyperthermia induced by iron oxide nanoparticles, is another efficient way to deliver the drugs to the targeted site. The nanoparticles are also designed to respond to the change in environment pH or enzymes to trigger the release of the antibiotics. This article offers an overview of the benefits of antibacterial nanosystems for treating infectious diseases.

Antimicrobial properties of hydrophobic compounds in garlic: Allicin, vinyldithiin, ajoene and diallyl polysulfides

Allium plants, such as garlic, onion and leek have long been known to be effective in the therapy of infectious diseases. In particular, garlic has a greater antimicrobial activity than other Allium plants as it contains several hydrophobic antimicrobial compounds, such as allicin, vinyldithiins, ajoenes and diallyl polysulfides. Allicin is a characteristic sulfur-containing compound found in raw garlic produced from alliin and exhibits antimicrobial activity against both Gram-positive and Gram-negative bacteria. In addition, allicin has been reported to inhibit the biofilm formation of bacteria, which is a major cause of bacterial resistance to the antibiotic treatment of infections, by regulating quorum sensing in microorganisms. Other hydrophobic compounds also have similar inhibitory effects on bacteria as allicin. These biological properties of garlic-derived hydrophobic compounds can be used to enhance the effects of existing drugs and may thus be used in the treatment of infections, such as by preventing drug resistance through the inhibition of biofilm formation. In this review, we summarize the effects of hydrophobic compounds of garlic on bacteria.

A brief overview on nano-sized materials used in the topical treatment of skin and soft tissue bacterial infections

Introduction: Skin and soft tissue infections are a significant clinical problem that can happen anywhere on the body. Bacteria are the most common cause of skin and soft tissue infections in humans. Despite the fact that there is a lot of antimicrobial agents and antibiotics for elucidating bacterial infections, the prevention and control of infectious diseases continue to be one of the greatest challenges for public health worldwide. At the present time, an alarming increase in multidrug resistance instantly requests to find suitable alternatives to current antibiotics. Therefore, drug resistance has been attempted to be resolved by the development of new classes of antimicrobial agents or targeted delivery systems for antibacterial drugs using nanotechnology.Area covered: The present review summarizes the emerging topical efforts to support the use of nano-sized materials as a new opportunity to combat today's skin infectious diseases.Expert opinion: Nano-sized materials can overcome the stratum corneum barrier and deliver drugs specifically to bacterial skin infections with trivial side effects. Depending on the physicochemical characteristics of nano-scaled materials, they can specifically be selected to target bacterial pathogens and also to get into the skin layers. These systems can overcome the antibiotic-resistance mechanisms and help us to the design of novel topical formulations that will make administration of antibacterial compounds safer, easier and more convenient.

Silver nanoparticles as an effective disinfectant: A review

The paradigm modifications in the metallic crystals from bulky to micro-size to nano-scale have resulted in excellent and amazing properties; which have been the remarkable interests in a wider range of applications. Particularly, Ag NPs have much attention owing to their distinctive optical, chemical, electrical and catalytic properties that can be tuned with surface nature, size, shapes, etc. and hence these crystals have been used in various fields such as catalysis, sensor, electronic components, antimicrobial agents in the health industry etc. Among them, Ag NPs based disinfectants have paid attention due to the practical applications in our daily life. Therefore the Ag NPs have been used in different sectors such as silver-based air/water filters, textile, animal husbandry, biomedical and food packaging etc. In this review, the Ag NPs as a disinfectant in different sectors have been included in detail.

Characterization of the antibacterial activity of Bald's eyesalve against drug resistant Staphylococcus aureus and Pseudomonas aeruginosa

Bald's eyesalve is an Anglo-Saxon medicinal remedy that has been used through ancient times to treat eye sty infections and may represent a source of ancientbiotics. This study assessed the efficacy of Bald's eyesalve against several strains of Staphylococcus aureus and Pseudomonas aeruginosa, including a multi-drug resistant phenotype, and identified the principal compound conveying antibacterial activity. Bald's eyesalve formulations were produced by combining garlic, onion or leek, wine, bovine bile, and brass, with specific ingredient omissions in several formulations, followed by incubation at 4 °C for 9 days. Bald's eyesalve formulation ES-GBBr exhibited the greatest antibacterial activity against S. aureus and P. aeruginosa. Fractionation of ES-GBBr using molecular size exclusion and organic solvent partitioning isolated its antibacterial activity to the small molecule nonpolar fraction, and 1D 1H NMR revealed the identity of the antibacterial agent to be allicin. Depletion of allicin from this fraction by addition of exogenous cysteine established that all observable growth inhibition originated from allicin. Quantification of allicin demonstrated that its concentration was significantly greater in ES-GBBr compared to the ES-O formulation; however, this was not due to greater yield. The antibacterial activity of allicin against S. aureus was antagonized by other ingredients within Bald's eyesalve, whereas they were additive or synergistic against P. aeruginosa. These results suggest that neither leek nor onion is necessary for the antibacterial efficacy of Bald's eyesalve against S. aureus or P. aeruginosa, and while allicin was identified as the principal antibacterial agent present, its activity is influenced differentially in the presence of additional Bald's eyesalve ingredients when used against S. aureus compared to P. aeruginosa. Ancientbiotics may provide a source of promising antibacterials; however, identifying the source of activity and assessing distinct formulations for cooperative effects are essential to using ancient remedies, such as Bald's eyesalve, effectively against drug resistant pathogens.

Augmented antibacterial activity of ampicillin with silver nanoparticles against methicillin-resistant Staphylococcus aureus (MRSA)

At present, including failed attempts, it takes about 15 years and costs totaling up to $2.6 billion to take a promising new compound from laboratory to the market. Increasing drug resistance among microbial pathogens has led to a growing interest in exploring novel methods to enhance the efficacy of existing drugs. Combination therapies involving two or more known antimicrobial methods, particularly those involving nanoparticles for combating the clinical problems associated with antibiotic resistance, have been garnering interest. In the current study, we determined whether a combination therapy involving silver nanoparticles, which are known for their antimicrobial activity, and the widely used antibiotic ampicillin can be effective against methicillin-resistant Staphylococcus aureus (MRSA). In the presence of sub-lethal dose of silver nanoparticles, ampicillin was found to be effective against MRSA. Indeed, the results show that silver nanoparticles and ampicillin act synergistically, with the effect being more pronounced when a lower concentration of ampicillin is present. When present at a higher concentration, ampicillin coats the silver nanoparticle, preventing the direct interaction of nanoparticles and bacteria. This study discusses the possible applications of combination antimicrobial therapies involving silver nanoparticles for therapeutic treatments.

Synergistic Effect of Diallyl Sulfide With Zinc Oxide Nanorods: A Novel and Effective Approach for Treatment of Acute Dermatitis in Model Animals

Besides inciting persistent and recurrent nosocomial afflictions, Staphylococcus aureus (S. aureus), a biofilm forming pathogen, poses an increased risk of several skin as well as respiratory tract infections as well. Emerging antimicrobial resistance trend asks to search for an alternate non-antibiotic based option to combat S. aureus pathogen. In the present study, we evaluated synergistic antimicrobial potential of Zinc oxide nanorods (ZnO-NRs) and diallyl sulphide (DAS) emulsion against methicillin resistant Staphylococcus aureus (MRSA). The antimicrobial assessment study suggests that the ZnO-NR and DAS emulsion effectively suppressed both sensitive S. aureus as well as MRSA isolates. The combination treatment showed enhanced activity even at a lower concentration as compared to the single treatment based on ZnO-NRs and DAS emulsion alone. The ZnO-NRs-DAS combination showed significant inhibition of MRSA biofilm as well. The data suggest that a combination therapy, comprising of ZnO-NRs and DAS emulsion, successfully treated experimental dermatitis infection caused by MRSA in mice model.

Effects of Silver Nanoparticles on Multiple Drug-Resistant Strains of Staphylococcus aureus and Pseudomonas aeruginosa from Mastitis-Infected Goats: An Alternative Approach for Antimicrobial Therapy

Recently, silver nanoparticles (AgNPs) have been widely used in various applications as antimicrobial agents, anticancer, diagnostics, biomarkers, cell labels, and drug delivery systems for the treatment of various diseases. Microorganisms generally acquire resistance to antibiotics through the course of antibacterial therapy. Multi-drug resistance (MDR) has become a growing problem in the treatment of infectious diseases, and the widespread use of broad-spectrum antibiotics has resulted in the development of antibiotic resistance by numerous human and animal bacterial pathogens. As a result, an increasing number of microorganisms are resistant to multiple antibiotics causing continuing economic losses in dairy farming. Therefore, there is an urgent need for the development of alternative, cost-effective, and efficient antimicrobial agents that overcome antimicrobial resistance. Here, AgNPs synthesized using the bio-molecule quercetin were characterized using various analytical techniques. The synthesized AgNPs were highly spherical in shape and had an average size of 11 nm. We evaluated the efficacy of synthesized AgNPs against two MDR pathogenic bacteria, namely, Pseudomonas aeruginosa and Staphylococcus aureus, which were isolated from milk samples produced by mastitis-infected goats. The minimum inhibitory concentrations (MICs) of AgNPs against P. aeruginosa and S. aureus were found to be 1 and 2 μg/mL, respectively. Our findings suggest that AgNPs exert antibacterial effects in a dose- and time-dependent manner. Results from the present study demonstrate that the antibacterial activity of AgNPs is due to the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and leakage of proteins and sugars in bacterial cells. Results of the present study showed that AgNP-treated bacteria had significantly lower lactate dehydrogenase activity (LDH) and lower adenosine triphosphate (ATP) levels compared to the control. Furthermore, AgNP-treated bacteria showed downregulated expression of glutathione (GSH), upregulation of glutathione S-transferase (GST), and downregulation of both superoxide dismutase (SOD) and catalase (CAT). These physiological and biochemical measurements were consistently observed in AgNP-treated bacteria, thereby suggesting that AgNPs can induce bacterial cell death. Thus, the above results represent conclusive findings on the mechanism of action of AgNPs against different types of bacteria. This study also demonstrates the promising use of nanoparticles as antibacterial agents for use in the biotechnology and biomedical industry. Furthermore, this study is the first to propose the mode of action of AgNPs against MDR pathogens isolated from goats infected with subclinical mastitis.

Antinociceptive and Anti-Inflammatory Activities of Teucrium persicum Boiss. Extract in Mice

Background. Therapeutic properties of Teucrium species as antioxidant, antibacterial, analgesic, anticancer, diuretic, and tonic compounds have been proved earlier. Materials and Methods. In this study, the antinociceptive and anti-inflammatory effects of the aqueous extract of Teucrium persicum on chronic pain, sciatic nerve ligation as a model of neuropathic pain, and inflammatory models were investigated by formalin, hot-plate, and cotton pellet-induced granuloma models in mice, respectively. T. persicum aqueous extracts (100, 200, and 400 mg/kg) were orally gavaged for one week. On 8th day, the time spent and the number of lickings were recorded in formalin test. Morphine and Diclofenac were used intraperitoneally as positive controls. In sciatic nerve ligated animals, as a model of neuropathic pain, doses (100, 200, and 400 mg/kg) of T. persicum extract (TPE) were orally gavaged for 14 consecutive days. The analgesic effect of this extract was examined 14 days after sciatic nerve ligation using the hot-plate test. Controls received saline and Imipramine (40 mg/kg, i.p.) was used a positive control for neuropathic pain model. Results. In the formalin test, a week oral gavage of all TPE doses (100, 200, and 400 mg/kg) caused a significant decrease on the licking response compared to the control negative animals. In the hot-plate test, doses of 200 and 400 mg/kg showed significant analgesic effects in sciatic nerve ligated animals. Oral gavaged of TPE revealed significant analgesic effect on chronic pain in both formalin test and sciatic nerve ligated animals. The TPEs did not have any significant anti-inflammatory effects in cotton pellet-induced granuloma formation in mice. Conclusions. These results suggest that the aqueous extract from T. persicum Boiss. produced antinociceptive effects. Its exact mechanism of action still remains indistinct.

Modulatory role of garlicin in migration and invasion of intrahepatic cholangiocarcinoma via PI3K/AKT pathway

Increasing evidences have indicated the role of garlicin in inhibiting the progression of various tumors including glioma, pulmonary carcinoma and pancreatic carcinoma, via mediating cell apoptosis or cell cycle. The regulatory effect and related molecular mechanism of garlicin in intrahepatic cholangiocarcinoma, however, remained unknown. This study thus aimed to investigate this scientific issue. HCCC-9810 cell line was treated with serially diluted garlicin, followed by cell proliferation assay using MTT approach. Transwell migration and invasion assays were further employed the regulatory effect of garlicin. The expression level of p-AKT and AKT proteins in tumor cells was quantified by Western blot. The growth of tumor cells was significantly inhibited by high concentration of garlicin (> 1.5 μM). Lower concentration of garlicin showed dose-dependent inhibition of tumor cell invasion and migration. After using specific agonist IGF-1 (50 ng/mL) of PI3K/AKT signaling pathway, such facilitating effects of garlicin were depressed (P < 0.05). Western blotting showed significantly decreased phosphorylation level of AKT after treated with gradient concentrations of garlicin, while leaving the total AKT protein level unchanged. Garlicin may inhibit the invasion and migration of intrahepatic cholangiocarcinoma cells via inhibiting PI3K/AKT signaling pathway.

Composition, Cytotoxic and Antimicrobial Activities of Satureja intermedia C.A.Mey Essential Oil

In this study, the essential oil (EO) constituents from the aerial parts of Satureja intermedia C.A.Mey were detected by GC and GC/MS. The antimicrobial activity of EO on oral pathogens and its cytotoxicity to human cancer cells were determined by the microbroth dilution method and the crystal violet staining method, respectively. Thirty-nine compounds were identified and the main EO constituents were γ-terpinene (37.1%), thymol (30.2%), p-cymene (16.2%), limonene (3.9%), α-terpinene (3.3%), myrcene (2.5%), germacrene B (1.4%), elemicine (1.1%) and carvacrol (0.5%). The S. intermedia EO showed a concentration-dependent decrease in viability of Hep-G2 (hepatocellular carcinoma) and MCF-7 (breast adenocarcinoma) human cancer cell lines (p < 0.05). Antimicrobial screening of S. intermedia EO demonstrated slight antibacterial and antifungal activities against Streptococcus mutants, S. salivarius, Enterococcus faecalis, Staphylococcus aureus, Candida albicans and C. glabrata. Further preclinical studies are needed to assess the efficacy and safety of S. intermedia EO as a new promising anticancer agent.

Inhibition of Staphylococcus aureus Adhesion to the Surface of a Reticular Heavyweight Polypropylene Mesh Soaked in a Combination of Chlorhexidine and Allicin: An In vitro Study

INTRODUCTION

Presoaking meshes for hernia repair with antiseptics prior to implantation could decrease the adhesion of microorganisms to the material surface and reduce the risk of antibiotic resistances. In this work, we evaluate chlorhexidine and allicin (natural antiseptic not yet tested for these purposes) against vancomycin as antiseptics to be used in the pretreatment of a heavyweight polypropylene mesh using an in vitro model of bacterial contamination.

METHODS

Solutions of saline, vancomycin (40 µg/mL), allicin (1,000 µg/mL), chlorhexidine (2%-0.05%) and the combination allicin-chlorhexidine (900 µg/mL-0.05%) were analyzed with agar diffusion tests in the presence of 106 CFU Staphylococcus aureus ATCC25923. Additionally, sterile fragments of Surgipro (1 cm2) were soaked with the solutions and cultured onto contaminated agar plates for 24/48/72 h. The antimicrobial material DualMesh Plus was utilized as positive control. At every time, the inhibition zones were measured and the bacterial adhesion to the mesh surface quantified (sonication, scanning electron microscopy). Cytotoxicity of the treatments was examined (alamarBlue) using rabbit skin fibroblasts.

RESULTS

The largest zones of inhibition were created by allicin-chlorhexidine. Chlorhexidine was more effective than vancomycin, and allicin lost its effectiveness after 24 h. No bacteria adhered to the surface of the DualMesh Plus or the meshes soaked with vancomycin, chlorhexidine and allicin-chlorhexidine. On the contrary, saline and allicin allowed adherence of high loads of bacteria. Vancomycin had no toxic effects on fibroblasts, while allicin and chlorhexidine exerted high toxicity. Cytotoxicity was significantly reduced with the allicin-chlorhexidine combination.

CONCLUSIONS

The use of antiseptics such as chlorhexidine, alone or combined with others like allicin, could represent an adequate prophylactic strategy to be used for hernia repair materials because soaking with these agents provides the mesh with similar antibacterial properties to those observed after soaking with vancomycin, similar to the effect of DualMesh Plus.

Phytochemical compositions and biological activities of essential oil from Xanthium strumarium L

The chemical composition of the essential oil (EO) from fresh cocklebur (Xanthium strumarium L.) leaves was investigated by GC-MS. The antimicrobial activity of the EO was tested against Gram-positive and Gram-negative bacteria and fungi. Scolicidal activity was assayed against Echinococcus granulosus protoscolices. In total, 34 compounds were identified, accounting for 98.96% of the EO. The main compounds in the EO were cis-β-guaiene (34.2%), limonene (20.3%), borneol (11.6%), bornyl acetate (4.5%), β-cubebene (3.8%), sabinene (3.6%), phytol (3.1%), β-selinene (2.8%), camphene (2.2%), α-cubebene (2.4%), β-caryophyllene (1.9%), α-pinene (1.8%) and xanthinin (1.04%). The antibacterial and antifungal screening of the EO showed that all assayed concentrations significantly inhibited the growth of Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger (MIC = 0.5 ± 0.1, 1.3 ± 0.0, 4.8 ± 0.0, 20.5 ± 0.3, 55.2 ± 0.0 and 34.3 ± 0.0 µg/mL, respectively). The scolicidal assay indicated that the EO exhibited a significant activity against E. granulosus protoscolices. To the best of our knowledge, this is the first report on the scolicidal activity of X. strumarium. Because of the emergence of antimicrobial drug resistance, the study of new effective natural chemotherapeutic agents, such as the X. strumarium EO, possibly with low side effects, represents a very promising approach in biomedical research.