Significant Antibacterial Effect Research Articles

Photodynamic Cationic Ultrasmall Copper Oxide Nanoparticles-Loaded Liposomes for Alleviation of MRSA Biofilms.

As we enter the post-antibiotic era, the rise of antibiotic-resistant pathogenic bacteria is becoming a serious threat to public health. This problem is further complicated by antibiotic-resistant biofilms, for which current treatment options are limited. To tackle this challenge, we propose a novel approach that involves the use of photodynamic cationic pH-sensitive liposomes loaded with ultra-small copper oxide (Ce6@Lipo/UCONs) to effectively eliminate drug-resistant bacteria and eradicate biofilms while minimizing safety concerns and the risk of resistance development. Our study demonstrates that Ce6@Lipo/UCONs have minimal toxicity to mammalian cells and can significantly enhance the association affinity with methicillin-resistant Staphylococcus aureus (MRSA) as confirmed by fluorescent microscope and flow cytometry, thereby greatly improving the bactericidal effect against planktonic MRSA. The cationic nature of Ce6@Lipo/UCONs also enables them to penetrate MRSA biofilms and respond to the acidic microenvironment within the biofilm, effectively releasing the loaded UCONs. Our results indicate that Ce6@Lipo/UCONs could effectively eliminate biofilms under light irradiation conditions, as evidenced by both biomass analysis and scanning electron microscopy observations. In addition, significant antibacterial effects and abscess healing were observed in MRSA-infected mice treated with Ce6@Lipo/UCONs upon light irradiation, while good biocompatibility was achieved in vivo. Taken together, our findings suggest that photodynamic cationic ultrasmall copper oxide nanoparticles-loaded liposomes are a highly promising nano platform for combating antibiotic-resistant microbial pathogens and biofilms. The effective biofilm penetration and synergistic effect between photodynamic inactivation and metal sterilization make them a valuable tool for overcoming the challenges posed by antibiotic resistance.

Novel and efficient synthesis of lithium crown ether metal–organic framework nanoparticles (15C5-Li MOF@Bi2O3@TiO2 NPs): Characterization and evaluation of its in vitro antibacterial studies

Novel lithium crown ether metal-organic framework nanoparticles ([email protected]2O3@TiO2 NPs) have been well documented for their biological activity as anti-bacterial entities. An efficient synthesis of novel lithium crown ether metal-organic framework nanoparticles has been reported in this study using Bi2O3, TiO2, and LiCl to investigate its antibacterial properties. The newly synthesized nanoparticles ([email protected]2O3@TiO2 NPs) found a significant antibacterial effect. A comparative study of gram-positive bacteria with Ofloxacin demonstrates good control for antibacterial properties. Similarly, gram-negative bacteria were studied to compare antibacterial properties using reference control Ofloxacin. The results against the gram-negative bacteria were found dose-dependent and more effective than against gram-positive bacteria, causing cell lysis with a change in phosphotyrosine profile affecting bacterial signal transduction and impeding the growth of organisms. To know the morphological study, FESEM analysis, energy dispersive X-ray (EDX) analysis, and elemental mapping of novel nanoparticles are performed, demonstrating more stability and antibacterial efficacy of prepared nanoparticles, which were spherical on mesoporous sheets. The crystalline pattern of NPs is studied using UV-visible, XRD, and FTIR spectroscopic analysis supports the structure of the novel ([email protected]@TiO2 NPs).

Eco-friendly high-rate formation of silver nanoparticles in agave inulin and its bactericidal effect against Escherichia coli

Abstract A high rate of silver nanoparticle formation, effective against the Escherichia coli (E. coli) bacterium, was obtained for the first time by means of a simple, eco-friendly, and low-cost green method in a solution of agave inulin. The study was carried out using the traditional method, in which the effects of the concentration of agave inulin, AgNO3, temperature, and pH on the synthesis were analyzed by UV-Vis spectroscopy and transmission electron microscopy (TEM). Most of the nanoparticles produced were spherical with a size less than 10 nm. In a sample with 20 mg/mL of agave inulin, 1 mM of AgNO3, T = 23°C, and pH = 12, the highest percentage of Ag+ ions available in the solution were reduced for the formation of nanoparticles in less than 40 min, whereas a sample prepared with 60 mg/mL of agave inulin, 10 mM of AgNO3, T = 23°C, pH = 12, and a storage time of 40 min showed a significant bactericidal effect on the E. coli strain. Agave inulin is a good biological compound for the formation of small, spherical silver nanoparticles. A pH of 12 favors a higher production speed of the silver nanoparticles and better use of the available Ag+ ions. In addition to this, the concentration of AgNO3 is a determining factor for increased formation of the nanoparticles necessary to bactericidal effect.

Electrospun Nanofibrous Biocomposite of Royal Jelly/Chitosan/Polyvinyl Alcohol (RJ/CS/PVA) Gel as a Biological Dressing for P. aeruginosa-Infected Burn Wound.

Burn wounds are vulnerable to various infections due to damage to the tissue and changes in immune responses. Pseudomonas aeruginosa is a critical bacterium that can cause burn wound infections, which can be life-threatening and delay wound healing. Therefore, it is essential to develop an efficient strategy to prevent the spread of infection in burn wounds. The present study aims to investigate the effectiveness of electrospun nanofibers of royal jelly on a chitosan/polyvinyl alcohol polymer scaffold in repairing burn wounds infected with Pseudomonas aeruginosa. To achieve this, the researchers analyzed the morphology and physicochemical properties of the synthesized nanofibers using SEM, FTIR, BET, and TGA analyses. They also examined the antibacterial properties of the nanofibers using agar diffusion and spread plate techniques. In addition, hemolysis tests were carried out to assess biocompatibility. Finally, the ability of the nanofibers to repair burn wounds infected with Pseudomonas aeruginosa was evaluated using a laboratory mouse model. The study results showed that the synthesized nanofibers had desirable morphology and physicochemical properties and significant antibacterial effects in both in vitro and in vivo conditions. Also, loading RJ into the polymer scaffold significantly reduced erythrocyte lysis. The wound healing and contraction rates were significantly higher than the control groups, and tissue repair, re-epithelialization, and collagen synthesis occurred faster, preventing the spread of infection to deeper tissue areas. Based on these findings, the synthesized system has the potential to serve as a suitable substitute for some invasive treatments and chemical drugs to improve chronic wounds and manage infection control in burn injuries.

The effect of antibacterial photodynamic therapy with diode laser on chromogenic bacteria associated with dental black staining: An in-vitro study

BackgroundAggregatibacter actinomycetemcomitan (A.a) and Actinomyces naeslundii (A.n) are two gram-negative chromogenic bacteria involved in the formation of dental black stainings. Our study aimed to investigate the antibacterial effect of photodynamic therapy (aPDT) using two photosensitizers, Methylene Blue (MB) and Indocyanine Green (ICG). Materials and methodsIn this in-vitro study, two isolates of each selected bacterium were cultured and treated as follows; Negative control with no treatment; CHX as a positive control; ICG; MB; ICG with 808 nm laser activation; and MB with 660 nm laser activation. The number of colonies (CFU/mL) was determined to compare the groups. The qualitative evaluation of biofilm formation was done by scanning electron microscopy of treated enamel pieces. The logarithmic values of the colony counts were compared using One-way ANOVA and the Welch test Tukey HSD and Games-Howell tests were used for multiple comparisons. P-values of less than 0.05 were considered statistically significant. ResultsThe use of ICG alone or along with laser irradiation at the wavelength of 808 nm significantly reduced the number of colonies of A.a and A.n bacteria. Comparing the colony counts in the MB group with the positive control showed no significant decrease in bacterial load. On the contrary, activation of MB with 660 nm radiation of diode laser showed a significant antibacterial effect. The density of bacterial biofilm was significantly lower in the groups treated with MB and ICG without laser activation than in the control group; however, the reduction in bacteria biofilm density was more robust using photodynamic therapy with ICG. ConclusionaPDT using MB with 660 nm laser and ICG with 808 nm laser significantly reduced the number of chromogenic A.a and A.n bacteria, and photodynamic therapy with ICG was proven to be significantly more effective than MB with or without laser radiation.

Mechanism of ozone alleviation of malignant ascites in hepatocellular carcinoma through the inhibition of neutrophil extracellular traps.

Malignant ascites in hepatocellular carcinoma is usually a sign of advanced disease and poor prognosis and is also thought to be associated with chronic inflammation mediated by neutrophil extracellular trap (NET) networks. Although ozone, a strong oxidant, has significant antibacterial and anti-inflammatory effects, its effectiveness in treating malignant liver ascites is unclear. We first measured the levels of NETs in the peripheral blood of patients with liver cancer and healthy individuals. Next, we constructed the H22 tumor-bearing mouse model and observed the abdominal girth, body weight, survival rate, and survival time in each group; we marked the proteins associated with NETs in mouse intestinal tissues by immunofluorescence; cf-DNA and cytokines in ascites such as: tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), matrix metalloprotein 9 (MMP-9), and interferon gamma (IFN-γ) levels in ascites were measured by enzyme-linked immunosorbent assay. The expression levels of phosphorylated adenylate-activated protein kinase (P-AMPK) and scavenger receptor-A (SR-A) were detected by immunocytochemistry in the intestinal tissues of each group of mice. We further examined the expression of P-AMPK and SR-A proteins in ascites deposits by Western blotting. The results show, the plasma levels of NETs were higher in patients with hepatocellular carcinoma than in normal subjects (P < 0.01). Abdominal girth and body weight were significantly reduced in the ozone-treated group compared with the model group, while survival and survival time were dose dependently increased (both P < 0.05). NET-associated guanine histone H3 and myeloperoxidase were abundantly expressed at neutrophil aggregates in the intestinal tissues of the model mice, whereas their expression was significantly reduced in the ozone-treated group. The levels of cf-DNA, IL-6, IFN-γ, MMP-9, VEGF, and TNF-α were dose dependently increased in the ascites of H22 tumor-bearing mice in the ozone-treated group compared with the model group (all P < 0.01), while the expression of P-AMPK and SR-A proteins was increased in the ozone-treated group compared with the model group. Ozone showed significant antiperitoneal fluid production properties in H22 tumor-bearing mice, and ozone reduced peritoneal fluid production by activating AMPK and up-regulating SR-A phagocytosis damage-associated molecular patterns to reduce the production of NETs. This suggests that ozone could be used as a new drug for the treatment of malignant ascites in hepatocellular carcinoma.

Synthesis and Biological Activities of Oxazolidinone Pleuromutilin Derivatives as a Potent Anti-MRSA Agent.

A series of pleuromutilin derivatives containing an oxazolidinone skeleton were synthesized and evaluated in vitro and in vivo as antibacterial agents. Most of the synthesized derivatives exhibited potent antibacterial activities against three strains of Staphylococcus aureus (including MRSA ATCC 33591, MRSA ATCC 43300, and MSSA ATCC 29213) and two strains of Staphylococcus epidermidis (including MRSE ATCC 51625 and MSSE ATCC 12228). Compound 28 was the most active antibacterial agent in vitro (MIC = 0.008-0.125 μg·mL-1) and exhibited a significant bactericidal effect, low cytotoxicity, and weak inhibition (IC50 = 20.66 μmol·L-1) for CYP3A4, as well as exhibited less possibility to cause bacterial resistance. Furthermore, in vivo activities indicated that the compound was effective in reducing MRSA load in a murine thigh infection model. Moreover, it clearly facilitated the healing of MRSA skin infection and inhibited the secretion of the TNF-α, IL-6, and MCP-1 inflammatory factors in serum. These results suggest that oxazolidinone pleuromutilin is a promising therapeutic candidate for drug-resistant bacterial infections.

Exploring the Synergistic Antimicrobial Potential of Ethanolic Leaf Extracts from Melia azedarach and Solanum incanum against Escherichia coli

Medicinal plants have been used for the maintenance of health for many years. Emerging cases of adverse drug reactions, high cost, and antimicrobial resistance using a single antimicrobial drug have heightened the need for research into plant sources of antimicrobial activity like Melia azedarach and Solanum incanum. This research investigated the synergistic antimicrobial activity exhibited by ethanolic leaf extracts obtained from Melia azedarach and Solanum incanum when tested against the pathogenic bacterium Escherichia coli. The study aimed to characterize the presence and composition of phytochemicals in the individual extracts, thereby elucidating their contribution to the observed antimicrobial effects. Additionally, minimum inhibitory concentration (MIC) assays and disc diffusion tests were performed to determine the optimal concentration required to inhibit the growth of Escherichia coli. Solanum incanum at a concentration of 2g/ml showed an average zone of inhibition of 6.92mm while Melia azedarach exhibited a zone of inhibition of 6.97 mm for Escherichia coli. The combined extracts showed a zone of inhibition of 8.34 mm for Escherichia coli. The minimum inhibitory concentration for Solanum incanum was 0.5g/ml while that of Melia azedarach was 1.4g/ml for Escherichia coli. Leaf extracts of both Melia azedarach and Solanum incanum had moderate to high levels of tannins, coumarins, flavonoids, and anthraquinones. Alkaloids and saponins were in low amounts in both extracts while steroidal glycosides were in moderate amounts in Melia azedarach but high in Solanum incanum. In conclusion, both plant extracts demonstrated significant antibacterial effects with both plants having a similar potency in terms of zone of inhibition diameter. The combined leaf extract of both plants had higher activity compared to individual plant extracts. We thus recommend that the combined extract can be used as an alternative modality for treating E. coli infections of mild severity without complications.

Chemical profiling and investigation of molecular mechanisms underlying anti-hepatocellular carcinoma activity of extracts from Polygonum perfoliatum L.

Polygonum perfoliatum L. is an herbal medicine that has been extensively used in traditional Chinese medicine to treat various health conditions ranging from ancient internal to surgical and gynecological diseases. Numerous studies suggest that P. perfoliatum extract elicits significant anti-tumor, anti-inflammatory, anti-bacterial, and anti-viral effects. Nevertheless, the underlying mechanisms of its anti-liver cancer effects remain poorly understood. Our study suggests that P. perfoliatum stem extract (PPLA) has a favorable safety profile and exhibits a significant anti-liver cancer effect both in vitro and in vivo. We identified that PPLA activates the cGMP-PKG signaling pathway, and key regulatory genes including ADRA1B, PLCB2, PRKG2, CALML4, and GLO1 involved in this activation. Moreover, PPLA modulates the expression of genes responsible for the cell cycle. Additionally, we identified four constituents of PPLA, namely taxifolin, myricetin, eriodictyol, and pinocembrin, that plausibly act via the cGMP-PKG signaling pathway. Both in vitro and in vivo experiments confirmed that PPLA, along with its constituting compounds taxifolin, myricetin, and eriodictyol, exhibit potent anti-cancer activities and hold the promise of being developed into therapeutic agents.

One-pot biogenic synthesis of gold nanoparticles@saponins niosomes: Sustainable nanomedicine for antibacterial, anti-inflammatory and anticancer therapeutics

Nanomedicine offers the promise of transforming modern medicine by facilitating precise and targeted therapeutic outcomes while reducing the adverse effects associated with conventional therapies. Nevertheless, the production process of nanomedicine often involves the use of hazardous and costly chemicals, leading to the creation of toxic by-products. This research paper presents a newly-developed, eco-friendly, one pot method of gold nanoparticles (AuNPs)@saponins niosomes synthesis by utilizing Sapindus mukorossi pericarps extract as both a reducing agent and stabilizer. The properties of the resulting AuNPs@saponins niosomes were analyzed in terms of composition, chemical structure, and morphology. Antibacterial activity of AuNPs@saponins niosomes was observed at concentrations of 50–100 µg/mL, and showed significant antibacterial effect on Staphylococcus aureus. The synthesized AuNPs@saponins niosomes also demonstrated potential as an anti-inflammatory agent, exhibiting an IC50 of 30.08 µg/mL, and displayed a dose-dependent anticancer effect against various human cancer cell lines up to 100 µg/mL. Among the tested cell lines, AuNPs@saponins niosomes exhibited the most effective cytotoxicity on MCF-7 cancer cells, displaying an IC50 of 54.13 µg/mL. Our results suggest that, this research has the potential to uncover the opportunities in the development of environmentally sustainable one-pot synthesis methods of metallic nanoparticles loaded niosomes, with applications in various fields for antibacterial, anti-inflammatory and anticancer therapeutics, offering promising avenues for advancement.

Antibacterial Effect of Melanoidins Derived From Xylose and Phenylalanine Against Bacillus cereus and Clostridium perfringens

Melanoidins produced from the combination of D-xylose and L-phenylalanine have been reported to exhibit strong antibacterial effects. This study investigated the influence of environmental factors, such as temperatures (10, 15, 20, 25, 30, 35, 40, and 45°C), pH (5.5, 6.0, 6.5, 7.0, 7.5, and 8.0), and water activity (aw: 0.99, 0.96, and 0.93), on the antibacterial effect of the melanoidins produced from the combination of D-xylose with L-phenylalanine against Bacillus cereus and Clostridium perfringens in culture media. Furthermore, freeze-dried powdered melanoidin was used to determine the minimum concentration for growth inhibition, to compare the antibacterial effect of the melanoidin with conventional food preservatives. The liquid melanoidins significantly inhibited the growth of B. cereus (up to 4 log CFU/mL at the maximum) and C. perfringens (up to 6.5 log CFU/mL at the maximum) regardless of the incubation temperatures. However, the remarkable difference between the presence and absence of the melanoidins was demonstrated in the range of 20–35°C as 4 log-cycle lower in B. cereus and 2 log-cycle lower in C. perfringens than those without the melanoidins. The antibacterial effect of the melanoidin on B. cereus was not influenced by pH from 5.5 to 7.0, which exhibited 2–3 log-cycle lower viable counts than those without the melanoidin. Only one log-cycle difference between with and without the melanoidin was shown in C. perfringens growth under the pH range of 5.5–7.0. Although there was no significant difference in the growth of B. cereus between three aw conditions, the melanoidin exhibited a significant antibacterial effect at aw 0.99 demonstrating 4 log-cycle lower viable numbers than those without the melanoidin. Minimum inhibitory concentration of the melanoidin powder for B. cereus and C. perfringens was 7 mg/mL and 15 mg/mL, respectively, regardless of the kind of foods. Furthermore, the melanoidin exhibited comparable antibacterial effect on B. cereus and C. perfringens to potassium sorbate and sodium benzoate under the same concentration as the minimum inhibitory concentration of the melanoidin, demonstrating 2 log-cycle reduction during 3 days of incubation period at 25°C. The results presented here suggest that the xylose- and phenylalanine-based melanoidin demonstrates the possibility to be an alternative food preservative.

ZnO-Doped Metal-Organic Frameworks Nanoparticles: Antibacterial Activity and Mechanisms.

Metal-Organic Frameworks (MOFs) offer new ideas for the design of antibacterial materials because of their antibacterial properties, high porosity and specific surface area, low toxicity and good biocompatibility compared with other nanomaterials. Herein, a novel antimicrobial nanomaterial, MIL-101(Fe)@ZnO, has been synthesized by hydrothermal synthesis and characterized by FTIR, UV-vis, ICP-OES, XRD, SEM, EDS and BET to show that the zinc ions are doped into the crystal lattice of MIL-101(Fe) to form a Fe-Zn bimetallic structure. MIL-101(Fe)@ZnO was found to be effective against a wide range of antibacterial materials including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter junii and Staphylococcus epidermidis. It has a significant antibacterial effect, weak cytotoxicity, high safety performance and good biocompatibility. Meanwhile, MIL-101(Fe)@ZnO was able to achieve antibacterial effects by causing cells to produce ROS, disrupting the cell membrane structure, and causing protein leakage and lipid preoxidation mechanisms. In conclusion, MIL-101(Fe)@ZnO is an easy-to-prepare antimicrobial nanomaterial with broad-spectrum bactericidal activity and low toxicity.

Antibacterial Activity and Mechanism of Canagliflozin against Methicillin-Resistant Staphylococcus aureus.

Diabetic foot infection (DFI) is a common complication in diabetes patients, with foot infections being the leading cause of amputations. Staphylococcus aureus is frequently found in diabetic foot infections, of which methicillin-resistant Staphylococcus aureus (MRSA) has become a major clinical and epidemiological challenge. Since MRSA strains are resistant to most β-lactam antibiotics, and also partially resistant to other antibiotics, treatment is difficult and costly. The emergence of drug-resistant bacteria often arises from overuse or misuse of antibiotics. Clinically, canagliflozin is commonly used for the treatment of type 2 diabetes. On this basis, we investigated the antibacterial activity and mechanism of canagliflozin against MRSA, with the aim to discover novel functions of canagliflozin and provide new insights for the treatment of MRSA. Using the microbroth dilution method to determine the half maximal inhibitory concentration of drugs, we found that canagliflozin not only can inhibit the growth of methicillin-sensitive Staphylococcus aureus (MSSA) but also exhibits antibacterial activity against MRSA. The IC50 values, at approximately 56.01 μM and 57.60 μM, were almost the same. At 12 h, canagliflozin showed a significant antibacterial effect against MRSA at and above 30 μM. In addition, its combined use with penicillin achieved better antibacterial effects, which were increased by about three times. Additive antibacterial activity (FICI = 0.69) was found between penicillin and canagliflozin, which was better than that of doxycycline and canagliflozin (FICI = 0.95). Canagliflozin also affected bacterial metabolic markers, such as glucose, ATP, and lactic acid. The results of crystal violet staining indicate that canagliflozin disrupted the formation of bacterial biofilm. Our electron microscopy results showed that canagliflozin distorted the bacterial cell wall. The results of RT-PCR suggest that canagliflozin down-regulated the expressions of biofilm-related gene (clfA, cna, agrC, mgrA, hld) and methicillin-resistance gene (mecA), which was related to MRSA. Molecular docking also indicated that canagliflozin affected some interesting targets of MRSA, such as the sarA, crtM and fnbA proteins. In conclusion, canagliflozin exhibits antibacterial activity against MRSA by affecting bacterial metabolism, inhibiting its biofilm formation, distorting the bacterial cell wall, and altering the gene expression of biofilm formation and its virulence. Our study reveals the antibacterial activity of canagliflozin against MRSA, providing a new reference for treating diabetic foot infections.

Application of f-FeNC@GOx cascade enzyme nanomaterials in the healing of infected wounds

AimsBacterial infection is a significant factor contributing to the deterioration of wounds, and the misuse of antibiotics has exacerbated bacterial resistance. Therefore, there is an urgent need to develop a novel antibacterial strategy to replace conventional therapies. This study aims to construct a self-activated cascade reaction nanozyme, f-FeNC@GOx, which triggers a cascade reaction in the presence of glucose. This cascade reaction generates highly toxic hydroxyl radicals (OH), thereby achieving the goal of eliminating bacteria and promoting wound healing. Material and methodsIn vitro antibacterial experiments, bacterial spread plate method, Live/Dead staining, and crystal violet staining were conducted to analyze the antibacterial ability and mechanism of f-FeNC@GOx. In vivo experiments, a mouse wound model was established, and H&E and Masson staining of wound tissues were performed to assess the antibacterial activity of the f-FeNC@GOx in vivo. Key findingsThe in vivo and in vitro experiments confirmed that f-FeNC@GOx exhibited significant antibacterial effect against both Staphylococcus aureus and Escherichia coli in the presence of glucose. Furthermore, it showed optimal wound healing performance in the wound models. SignificanceThese findings suggested that f-FeNC@GOx was a novel and effective antibacterial nanomaterial, which provided a promising antibacterial strategy using nanoenzyme based cascade reaction.

Fabrication of dual physically cross-linked polyvinyl alcohol/agar hydrogels with mechanical stability and antibacterial activity for wound healing

Bacterial infection is one of the most critical obstacles in wound healing, and severe bacterial infections can lead to inflammatory conditions and delay the healing process. Herein, a novel hydrogel based on polyvinyl alcohol (PVA), agar, and silk-AgNPs was prepared using a straightforward one-pot physical cross-linking method. The in situ synthesis of AgNPs in hydrogels exploited the reducibility of tyrosine (Tyr tyrosine) in silk fibroin, which endowed the hydrogels with outstanding antibacterial qualities. In addition, the strong hydrogen bond cross-linked networks of agar and the crystallites formed by PVA as the physical cross-linked double network of the hydrogel gave it excellent mechanical stability. The PVA/agar/SF-AgNPs (PASA) hydrogels exhibited excellent water absorption, porosity, and significant antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, in vivo experimental results confirmed that the PASA hydrogel significantly promoted wound repair and skin tissue reconstruction by reducing inflammation and promoting collagen deposition. Immunofluorescence staining showed that the PASA hydrogel enhanced CD31 expression to promote angiogenesis while decreasing CD68 expression to reduce inflammation. Overall, the novel PASA hydrogel showed great potential for bacterial infection wound management.

Phytochemical Screening and Antimicrobial Activity of Methanolic Extract of Cymbopogon schoenanthus (L.) (azkhar) Collected from Afif City, Saudi Arabia.

In Saudi Arabia, Cymbopogon schoenanthus (L.) has been traditionally used to treat a variety of diseases. This study aimed to investigate the crude methanolic extract of Cymbopogon schoenanthus (L.) phytochemical, chemical composition, and antibacterial activity. Phytochemical analysis revealed the presence of tannins, poly-tannins, steroids, alkaloids, essential oils, terpenoids, and flavonoids. The presence of functional groups such as -COOH, -OH, -C=O, and CH2 was revealed via FTIR spectroscopy. 13C and 1H NMR (nuclear magnetic resonance) were used to determine the types and number of protons (hydrogen atoms) and their electronic states. Using an agar well diffusion assay, methanolic extract of Cymbopogon schoenanthus (L.) inhibited the growth of some foodborne pathogenic bacteria in zones ranging from 8 to 25 mm in diameter. The minimum inhibitory concentration (MIC) for Staphylococcus aureus was 12.5 mg/mL, whereas it was 25 mg/mL for Bacillus cereus, Klebsiella pneumoniae, and Escherichia coli. The time-kill assay revealed a sharp decline in Staphylococcus aureus and Klebsiella pneumonia after 2 h at a concentration of 150 mg/mL, while Bacillus cereus and Escherichia coli showed a gradual decline with constant concentrations of 75 to 150 mg/mL. The minimum bactericide concentration (MBC) value for Bacillus cereus, Staphylococcus aureus, and Escherichia coli was 50 mg/mL, while it was 25 mg/mL for Klebsiella pneumoniae. In conclusion, our study revealed that Cymbopogon schoenanthus (L.) methanolic extract has a significant antibacterial effect, suggesting that it could be used to treat various foodborne pathogens.

The Efficacy of Application of Oral Antibiotic Loaded Polymethyl Methacrylate Against Staphylococcus aureus

Chronic osteomyelitis is still common in the developing world and presents a continuing therapeutic challenge. Local antibiotic therapy is performed as the first stage treatment algorithm for 4 to 8 weeks. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis and its treatment, it is important to find another effective and efficient treatment. Intravenous antibiotics and polymethylmethacrylate (PMMA) combination have shown effectiveness, but the potential of oral antibiotics and PMMA combination is still rare and is debatable. It aimed to compare efficacy among oral antibiotic-loaded PMMA in many concentrations (5%, 10%, 20%) and controls (0%) against Staphylococcus aureus. This experimental study was conducted in the Microbiology Department of Andalas University. The object was S. aureus. We used ten oral antibiotics and compared among its many concentrations (5%, 10%, 20%) and controls (0%). Data were analyzed by analysis of variance (ANOVA) test. The lowest counts of S. aureus were found in ciprofloxacin 20%, followed by tetracycline 10%, erythromycin 5%, rifampicin 10%, ofloxacin 20%, clindamycin 20%, amoxiclav 20%, cefixime 5%, cotrimoxazole 20%, and chloramphenicol 20% consecutively. All oral antibiotics loaded PMMA in each concentration might reduce the number of colonies up to 90%. A study in 2013 revealed that a combination of several antibiotics and PMMA was proven to be effective. The oral antibiotics loaded PMMA in various concentrations have a significant bactericidal effect on the growth of S. aureus and able to reduce the number of S. aureus.

Preparation of photothermal responsive, antibacterial hydrogel by using PVA-Alg and silver nanofibers as building blocks.

Introduction: Photothermal responsive, antimicrobial hydrogels are very attractive and have great potential in the field of tissue engineering. The defective wound environment and metabolic abnormalities in diabetic skin would lead to bacterial infections. Therefore, multifunctional composites with antimicrobial properties are urgently needed to improve the current therapeutic outcomes of diabetic wounds. We prepared an injectable hydrogel loaded with silver nanofibers for efficient and sustained bactericidal activity. Methods: To construct this hydrogel with good antimicrobial activity, homogeneous silver nanofibers were first prepared by solvothermal method and then dispersed in PVA-lg solution. After homogeneous mixing and gelation, injectable hydrogels (Ag@H) wrapped with silver nanofibers were obtained. Results: By virtue of Ag nanofibers, Ag@H exhibited good photothermal conversion efficiency and good antibacterial activity against drug-resistant bacteria, while the in vivo antibacterial also showed excellent performance. The results of antibacterial experiments showed that Ag@H had significant bactericidal effects on MRSA and E. coli with 88.4% and 90.3% inhibition rates, respectively. Discussion: The above results indicate that Ag@H with photothermal reactivity and antibacterial activity is very promising for biomedical applications, such as wound healing and tissue engineering.

Isolation, identification, and antibacterial evaluation of endophytic fungi from Gannan navel orange.

Gannan navel orange is a famous brand in China but the isolation of its endophytic fungi was rarely reported. In this study, a total of 54 strains of endophytic fungi were successfully isolated from the pulp, peel, twig, and leaf of Gannan navel orange; they were successfully identified to belong to 17 species of 12 genera. All these strains were fermented using potato-dextrose agar (PDA) medium, and their secondary metabolites were then extracted with ethyl acetate (EtOAc). The antibacterial assays of Escherichia coli (E. coli), methicillin-resistant Staphylococcus aureus (MRSA), and Xanthomonas citri subsp. citri (Xcc) were also performed for the EtOAc extracts of these strains. As a result, the extracts of both Geotrichum sp. (gc-1-127-30) and Diaporthe biconispora (gc-1-128-79) demonstrated significant antibacterial activities against Xcc, and the MIC value for the extract of Colletotrichum gloeosporioides against MRSA was low to 62.5 μg/mL. Moreover, the chemical components of the extracts of Colletotrichum sp., Diaporthe biconispora, and Annulohypoxylon atroroseum were primarily investigated, and they successfully led to the isolation of 24 compounds involving a new botryane sesquiterpene. Among the isolated products, compound 2 showed significant inhibitory activities toward SA, MRSA, E. coli, and Xcc with MIC values of 12.5, 3.1, 125, and 12.5 μg/mL, respectively. This study revealed that the endophytic fungi of Gannan navel orange showed high potency to produce secondary metabolites with significant antibacterial effects.

Inactivation of Salmonella using ultrasound in combination with Litsea cubeba essential oil nanoemulsion and its bactericidal application on cherry tomatoes

The presence of Salmonella in nature poses a significant and unacceptable threat to the human public health domain. In this study, the antibacterial effect and mechanism of ultrasound (US) combined with Litsea cubeba essential oil nanoemulsion (LEON) on Salmonella. LEON + US treatment has a significant bactericidal effect on Salmonella. Reactive oxygen species (ROS), malondialdehyde (MDA) detection, N-phenyl-l-naphthylamine (NPN) uptake and nucleic acid release assays showed that LEON + US exacerbated cell membrane lipid peroxidation and increased the permeability of the cell membrane. The results of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) showed that LEON + US treatment was able to alter cell morphology. It can be observed by flow cytometry (FCM) that LEON + US treatment can cause cell apoptosis. In addition, bacterial counts of cherry tomatoes treated with LEON (0.08 μL/mL) + US (345 W/cm2) for 9 min were reduced by 6.50 ± 0.20 log CFU/mL. This study demonstrates that LEON + US treatment can be an effective way to improve the safety of fruits and vegetables in the food industry.