Agar Disc Diffusion Research Articles

Characterization of protease-producing bacteria from garden soil and antagonistic activity against pathogenic bacteria

Bacteria play an essential role in various industrial processes, including food, medicine, and detergents, due to their ability to produce protease, a hydrolytic enzyme. This study aimed to identify and characterize protease-producing bacterial strains isolated from garden soil, evaluate their antibiotic susceptibility, and optimize conditions for enhanced protease production. Using skimmed milk agar medium and the gelatin hydrolysis method, 7 bacterial strains (S1, S2, S3, S4, S5, S6, and S7, respectively) were identified for protease production in garden soil. The bacteria were identified based on morphological studies, biochemical characterization, and the BIOLOG™ system, and the isolates were determined to be Bacillus cereus (S1), B. thuringiensis (S2), B. subtilis (S3), B. amyloliquefaciens (S4), Pseudomonas aeruginosa (S5), Macrococcus brunensis (S6), and B. schlegelii (S7). The antibiotic susceptibility test, performed using the Kirby-Bauer agar disc diffusion method, revealed that all isolates were resistant to penicillin, nitrofurantoin, and metronidazole. Additionally, B. subtilis and P. aeruginosa demonstrated antagonistic activity against pathogens. Optimal conditions for protease production were found to be a temperature range of 30°C to 40°C and a pH range of 6.5–7.5. Under these conditions, B. cereus (2.19 U/ml) and B. thuringiensis (2.12 U/ml) exhibited the highest protease activity. Further characterization of protease activity in B. cereus, P. aeruginosa, and M. brunensis under different physiological parameters revealed that maximum activity occurred within a pH range of 5.0–6.0 and temperatures between 30°C and 40°C. Protease activity increased in the presence of calcium (CaCl2) but decreased with the addition of urea. These findings underscore the significant industrial applications of proteases produced by these bacterial strains.

Unveiling the mechanism of essential oil action against skin pathogens: from ancient wisdom to modern science.

Essential oils are among the most well-known phyto-compounds, and since ancient times, they have been utilized in medicine. Over 100 essential oils have been identified and utilized as therapies for various skin infections and related ailments. While numerous commercial medicines are available in different dosage forms to treat skin diseases, the persisting issues include their side effects, toxicity, and low efficacy. As a result, researchers are seeking novel classes of compounds as substitutes for synthetic drugs, aiming for minimal side effects, no toxicity, and high efficacy. Essential oils have shown promising antimicrobial activity against skin-associated pathogens. This review presents essential knowledge and scientific information regarding essential oil's antimicrobial capabilities against microorganisms that cause skin infections. Essential oils mechanisms against different pathogens have also been explored. Many essential oils exhibit promising activity against various microbes, which has been qualitatively assessed using the agar disc diffusion experiment, followed by determining the minimum inhibitory concentration for quantitative evaluation. It has been observed that Staphylococcus aureus and Candida albicans have been extensively researched in the context of skin-related infections and their antimicrobial activity, including established modes of action. In contrast, other skin pathogens such as Staphylococcus epidermidis, Streptococcus pyogens, Propionibacterium acnes, and Malassezia furfur have received less attention or neglected. This review report provides an updated understanding of the mechanisms of action of various essential oils with antimicrobial properties. This review explores the anti-infectious activity and mode of action of essential against distinct skin pathogens. Such knowledge can be valuable in treating skin infections and related ailments.

Genetic characterization of blaCTX-M-65 in Salmonella Infantis and blaCMY-2 in Salmonella Heidelberg isolated from fresh ground turkey meat sold in supermarkets in Los Andes and San Felipe, Chile

Annually, food poisoning caused by non-typhoidal Salmonella (NTS) accounts for 40 million foodborne infections worldwide. Outbreaks due to multidrug-resistant NTS strains are associated with the consumption of poultry products. We aimed to determine the proportion of NTS in ground turkey meat available at supermarkets in two locations in Chile, characterizing their serovars, virulence traits, and antimicrobial resistance profiles. Between September and December 2018, we analyzed 47 samples of packed ground turkey meat purchased at 13 supermarkets. NTS were identified by MALDI-TOF, and antimicrobial susceptibility was determined by the disk-diffusion agar method. Whole genome sequencing was performed with MiSeq (Illumina) followed by Nullarbor analysis. NTS was detected in 6 out of 47 samples (12.8 %, 95 %CI: 6.0–25.1 %), identifying S. enterica serovar Infantis (n=4 isolates), serovar Agona (n=1 isolate), and serovar Heidelberg (n=1 isolate), respectively. S. Infantis belonged to sequence type (ST)32, differentiating two clones, whereas the S. Agona was ST13 and S. Heidelberg was ST15. S. Infantis strains were multidrug antibiotic resistant, harboring blaCTX-M-65, tetA, and mutations that confer fosfomycin resistance. Serovars Agona and Heidelberg showed tetracycline (tetB) and fosfomycin resistance (fosA7). Additionally, serovar Heidelberg showed resistance to sulfamethoxazole-trimethoprim, aminoglycosides, and carried the blaCMY-2 gene. This is the first report in Chile about NTS detected in raw ground turkey meat available in supermarkets. S. Infantis and S. Agona strains showed a phylogenetic relationship with strains of the same serovars isolated from the environment in our country. This situation would impact food poisoning and the dissemination of bacterial resistance between animals, humans, and the environment.

Biochemical properties of novel Carbon nanodot-stabilized silver nanoparticles enriched calcium hydroxide endodontic sealer.

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15-20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100-120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects.

Functionalization of PLA nanofibers with PCL blending and TiO2 nanoparticle addition

In this study, the functionality of polylactic acid (PLA) nanofibers was enhanced by blending polycaprolactone (PCL) and adding titanium dioxide nanoparticles. Various concentrations of TiO2 nanoparticles, ranging from 1 to 7% wt, were added to the PLA nanofibers. Optimal dispersion was observed at 3% wt TiO2, resulting in 493.64 ± 129.78 nm fiber sizes. Blending PLA with PCL in a 1:1 ratio yielded fibers with an average diameter of 513.20 ± 64.85 nm. The addition of TiO2 nanoparticles into the PLA/PCL blends increased fiber pore area due to the larger fiber size. Mechanical testing indicated that adding TiO2 nanoparticles enhanced the strength of the nanofibers slightly while ductility increased significantly. The results for the water uptake behavior of the fibers showed that TiO2 NP addition improved the water absorption. Antibacterial activity was evaluated against Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) using the agar disk diffusion method. TiO2 NPs added PLA and PLA/PCL nanofibers demonstrated inhibition zones of 10.46 ± 1.03 mm and 19.30 ± 1.47 mm against S.aureus, and 13.33 ± 1.15 mm and 21.71 ± 1.74 mm against E.coli, respectively.

In vitro antioxidant and antibacterial activities of aqueous extract of microalgae strain MRB-1, MRB-2, and MRB-3

Abstract The awareness growth of human health encourages market demand of functional food. Microalgae are promoted as natural resources for functional food, food additives and food preservatives, considering their metabolites and nutrient-rich components with diverse pharmacological activities. This study aims to evaluate the phytochemicals, antioxidant, and antibacterial activities of aqueous extracts of microalgae strain MRB-1, MRB-2, and MRB-3. The morphological surface of microalgae cells was analyzed using Scanning Electron Microscopy (SEM). The metabolites of the extract were conducted using Liquid Chromatography-High Resolution Mass Spectroscopy (LC-HRMS) with positive and negative ion modes. In addition, the antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and the antibacterial activity was assessed using the agar disk-diffusion method against gram-positive bacteria (Staphylococcus aureus ATCC 25923) and gram-negative bacteria (Escherichia coli ATCC 8739). The total phenolic contents (TPC) of the extract was determined using the Folin-Ciocalteu assay. The result revealed that the aqueous extract of microalgae strain MRB-1 had the highest scavenging activity toward DPPH radicals with a value of 24.33±1.44% at 0.8 mg/mL. This data was in accordance with the TPC of the extract, whereas the highest TPC was also obtained from strain MRB-1 extract (17.73±0.64 mg GAE/g extract). Meanwhile, the MRB-2 extract had the highest inhibition activity against S. aureus, with a value of 11.78±2.06 mm at 18 mg/mL. The results of this study indicated that microalgae from the peatlands potentially benefit to human health as a natural antioxidant and antibacterial source.

MOLECULAR DETECTION AND ANTIBACTERIAL ACTIVITY OF CITRUS SINENSIS PEEL EXTRACTS AGAINST STAPHYLOCOCCUS AUREUS AND KLEBSIELLA PNEUMONIA ISOLATED FROM WOUNDS

The global rise of resistant bacteria threatens the effectiveness of antibiotics, recommending that herbs' natural chemical constituents could provide alternative antimicrobial and insecticidal properties. The study evaluated Citrus sinensis peel extracts' impact on bacterial species isolated from wound samples collected from six hospitals. Quantitative Phytochemical analysis was conducted on the Citrus sinensis peel extracts, Isolates were tested biochemically and molecularly for detection and confirmation of Staphylococcus aureus and Klebsiella pneumonia. The study assessed the antibacterial activity of Citrus sinensis peel extracts using agar disc diffusion method, revealing significant bioactive compounds such as alkaloids, flavonoids, saponins, steroids, glycosides, and tannins. The extracts effectivity against Staphylococcus aureus and Klebsiella pneumonia comes from its bioactive phytochemical components. The result from the morphological and biochemical tests revealed the presence of Staphylococcus aureus, Klebsiella pneumonia, Staphylococcus epidermis, Pseudomonas aeruginosa, Escherichia coli and Enterobacter spp but only Staphylococcus aureus and Klebsiella pneumonia were confirmed by molecular method with a sequence identity of 99.35% and 97.41% respectively when analyzed using the Basic Local Alignment Search Tool (BLAST) of the NCBI package. The study revealed that Citrus sinensis peel extracts showed antibacterial activity against Staphylococcus aureus and Klebsiella pneumonia at different concentrations and Ciprofloxacin as a control. The ethanolic extract showed high activity, while the aqueous extracts showed significant activity. The study suggests Citrus sinensis peel has potential as an antibacterial agent for wound infection treatment, suggesting the need for its phytochemical composition quantification and purification.

Determination of Antibiotic Resistance Patterns of Beta-Lactamase-Producing Escherichia coli Strains from Kindirmo in Nasarawa Town, Nasarawa State, Nigeria

Study’s Novelty/Excerpt This study examined the antibiotic resistance patterns of beta-lactamase-producing Escherichia coli in Kindirmo, a traditional fermented milk product, in Nasarawa town, Nasarawa State, Nigeria. It identifies the prevalence of beta-lactamase-producing E. coli in Kindirmo, highlighting a 5.92% contamination rate and revealing complete resistance to six antibiotics among the isolates. The study underscores the public health risks associated with consuming Kindirmo and calls for stringent hygiene measures during its production and sale to protect consumers. Full Abstract This study investigates the antibiotic resistance patterns of beta-lactamase-producing Escherichia coli in Kindirmo in Nasarawa town, Nasarawa State, Nigeria. Over five months, 169 samples were collected from four sampling points. Escherichia coli was isolated using the streak-plating method and identified through biochemical tests. All isolates tested positive for beta-lactamase production. The agar-disc diffusion technique assessed the beta-lactamase-producing E. coli strains' susceptibility to 10 antibiotics. Out of 169 samples, 10 were contaminated with E. coli, resulting in a prevalence of 5.92%. The isolates showed complete resistance to six antibiotics, while 70% and 50% demonstrated susceptibility to ofloxacin, pefloxacin, and gentamicin, respectively. Six antibiotic-resistance phenotypes were identified among the E. coli isolates. The presence of beta-lactamase-producing E. coli in Kindirmo suggests that consuming the product in the area poses a risk to consumers. Authorities should enforce basic hygiene requirements during production and sales to safeguard public health.

Effect of phenylalanine arginyl β-naphthylamide on the imipenem resistance, elastase production, and the expression of quorum sensing and virulence factor genes in Pseudomonas aeruginosa clinical isolates.

Pseudomonas aeruginosa is one of the most important nosocomial pathogens that possess the ability to produce multiple antibiotic resistance and virulence factors. Elastase B (LasB) is the major factor implicated in tissue invasion and damage during P. aeruginosa infections, whose synthesis is regulated by the quorum sensing (QS) system. Anti-virulence approach is now considered as potential therapeutic alternative and/or adjuvant to current antibiotics' failure. The aim of this study is primarily to find out the impact of the efflux pump inhibitor (EPI) phenylalanine arginyl β-naphthylamide (PAβN) on the production of elastase B and the gene expression of lasI quorum sensing and lasB virulence factor in clinical isolates of P. aeruginosa. Five P. aeruginosa isolates recovered from patients with respiratory tract infections were examined in this study. Antimicrobial susceptibility of isolates was performed by the disk agar diffusion method. Effect of the PAβN on imipenem susceptibility, bacterial viability, and elastase production was evaluated. The expression of lasB and lasI genes was measured by quantitative real-time PCR in the presence of PAβN. All isolates were identified as multidrug-resistant (MDR) and showed resistance to carbapenem (MIC = 64-256µg/mL). Susceptibility of isolates to imipenem was highly increased in the presence of efflux inhibitor. PAβN significantly reduced elastase activity in three isolates tested without affecting bacterial growth. In addition, the relative expression of both lasB and lasI genes was diminished in all isolates in the presence of inhibitor. Efflux inhibition by using the EPI PAβN could be a potential target for controlling the P. aeruginosa virulence and pathogenesis. Furthermore, impairment of drug efflux by PAβN indicates its capability to be used as antimicrobial adjuvant that can decrease the resistance and lower the effective doses of current drugs.

Phytochemical profile, antioxidant, antidiabetic, and antimicrobial activities of Parkia timoriana bark extracts

Abstract. Sariwati A, Suryanti V, Sari F, Kamei I, Trisnawati EW. 2024. Phytochemical profile, antioxidant, antidiabetic, and antimicrobial activities of Parkia timoriana bark extracts. Biodiversitas 25: 2427-2433. Plants have various bioactive compounds that have pharmacological activity. Kedawung (Parkia timoriana (DC) Merr) is an indigenous plant in Indonesia that contains bioactive compounds. The leaves, bark, seeds, and roots of P. timoriana are commonly used in traditional medicine. The purpose of this study was to determine the chemical composition of P. timoriana bark extract and to assess its antioxidant, antidiabetic, and antibacterial activity. The bark of P. timoriana was extracted with various solvents that differ in polarity, such as water, methanol, ethyl acetate, and hexane. All extracts were investigated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl) (DPPH) free-radical and 2,2’-azinobis (3-ethylbenz-thiazoline-6-sulfonic-acid) (ABTS) scavenging ability. The in-vitro antidiabetic activity was carried out by ?-amylase and ?-glucosidase inhibition. Antibacterial and antifungal activities were determined by the agar disc diffusion method. Parkia timoriana bark extracts contained alkaloids, flavonoids, steroids, tannins, terpenoids, saponins, reducing sugars, and cardiac glycosides. The ethyl acetate extract possessed the highest total phenolics, alkaloids, flavonoids, saponins, tannic acid, and terpenoids. Secondary metabolites in all extracts contributed to free radical scavenging, antidiabetic, antibacterial, and antifungal properties. The P. timoriana bark contains natural chemical compounds that might be useful as therapeutic agents for producing bioactive products and pharmaceuticals in the future.

Virulence genes and pulsed-field gel electrophoresis profiles of Shiga toxin-producing Escherichia coli isolated from different food samples and patients with acute diarrhea.

Escherichia coli O157: H7 is one of the most important causes of hemorrhagic colitis, and hemolytic uremic syndrome. The present study aimed to isolate E. coli O157: H7 from foods and patients with hemorrhagic colitis, and identify Shiga toxin genes, phylogenetic comparison, and antibiotic resistance of the isolates. In total 400 samples, including patients stool and food were taken in Isfahan-Iran province. Phenotypic tests and PCR were performed to identify Shiga toxin-producing E. coli. The isolated strains were compared phylogenetically by PFGE. Agar disk diffusion was performed to identify the antibiotic resistance of the isolates. Totally, 5 isolates of fecal samples were E. coli O157, but only 2 isolates carried H7 gene. Also, 9 isolates of E. coli O157 were isolated from food samples that 3 isolates were E. coli O157: H7. The isolates carried stx1, stx2, hlyA and eaeA genes. Also, E. coli non-O157: H7 identified from samples that contained stx1, stx2, hlyA genes. The highest susceptibility to imipenem and the highest resistance to ampicillin and ciprofloxacin were observed. There was a similarity of 100% between the E. coli O157: H7 strains isolated from patients and raw milk and minced beef samples. Serotypes other than the O157 of E. coli are more prevalent in patients and food. The E. coli O157: H7 isolates from patients had 100% genetic similarity with minced meat and cow milk isolates, which indicates cattle are the most important reservoir of this bacterium in Iran.

Biological Activities, DFT Calculations, and Molecular Docking Simulation of Thymol‐Based Compounds

AbstractA set of thymol‐based derivatives (3 a–d) was synthesized and characterized. Quantum chemical calculations were performed to explain the nature of the transitions in the absorption spectra. These new compounds were tested as anticancer agents on human liver (HepG2), lung (A549), and colon (DLD‐1) cancer cell lines using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide method showing in some cases higher antiproliferative properties than the reference drug cisplatin. All synthesized compounds were also screened for their antimicrobial activity against a representative panel of Gram‐positive and Gram‐negative bacteria plus a pathogenic yeast species (Candida albicans ATCC90028) using agar disc diffusion and broth microdilution assays. Furthermore, we determined the antioxidant activity of these compounds by the DPPH free radical scavenging test. According to the minimum bactericidal concentration, minimum fungicidal concentration, and IC50 values, compound 3 c showed the highest antimicrobial activity, compound 3 d exhibited the highest antioxidant activity, while compounds 3 b and 3 c displayed higher cytotoxic activity than cisplatin against HepG2 and DLD‐1 cell lines albeit no selectivity towards healthy cells (HEK‐293T). Furthermore, docking simulations of the compounds towards two potential molecular targets, namely caspase‐3 protein (PDB ID: 3KJF) and Escherichia coli glucosamine‐6‐phosphate synthase (PDB ID: 2VF5), were performed in order to validate the anticancer and antimicrobial activities, respectively.

An in vitro evaluation of Hypericum perforatum loaded-chitosan nanoparticle/agarose film as a Wound dressing

Wound dressing materials are crucial for accelerating the healing period of chronic wounds. In this study, chitosan nanoparticles loaded with Hypericum perforatum (Hp) were modified with agarose to create wound-healing films and their antimicrobial potential was investigated in vitro. Chitosan (CS) nanoparticles and Hp-loaded nanoparticles were prepared using the ionic gelation method. The synthesized Hp-loaded CS nanoparticles were modified with agarose by the solvent-casting method. Antimicrobial assays were performed using the disk diffusion method and agar well diffusion method. The characterization of nanoparticles and films was performed by UV–Vis spectrophotometry, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FT-IR), mechanical testing, and swelling testing. The results showed that Hypericum perforatum was loaded into chitosan nanoparticles with a 90.1 ± 2.53 % yield. The sizes of the Hypericum perforatum-loaded chitosan nanoparticles and chitosan nanoparticles were 156 ± 22 nm and 69 ± 4.2 nm, respectively. The CS-Hp/Agarose film showed no cytotoxic effect on L929 fibroblast cells and maintained cell viability for 72 h. These results indicate that Hp might be used in wound healing due to its antimicrobial and cell growth-promoting properties.

Evaluation of Antimicrobial Effect of Ginger, Apple Cider Vinegar against Streptococcus Mutans, Enterococcus Faecalis and Candida Albicans.

Oral infections are most frequently caused by three oral microorganisms: Streptococcus mutans (S. mutans), Enterococcus faecalis (E. faecalis), and Candida albicans (C. albicans). To evaluate antimicrobial potential of 10% ginger extract (GE) and apple vinegar against S. Mutans, E. faecalis, and C. albicans. The GE and apple cider vinegar (ACV) were tested for microbiological evaluation to identify the inhibitory zone using the agar disk diffusion test against S. mutans, C. albicans, and E. faecalis. The 10% ethanolic GE and ACV showed a maximum zone of inhibition zone against S. mutans, E. Faecalis, and C. albicans. The intragroup comparison was insignificant. Apple vinegar and 10% ethanolic GE were shown to have good antimicrobial properties against all three tested pathogens.

Utilization of the Shensheng-Piwen changed medicinal powder extracts combines metal-organic frameworks as an antibacterial agent.

Widespread opportunistic pathogens pose a serious threat to global health, particularly in susceptible hospital populations. The escalating crisis of antibiotic resistance highlights the urgent need for novel antibacterial agents and alternative treatment approaches. Traditional Chinese Medicine (TCM) and its compounds have deep roots in the treatment of infectious diseases. It has a variety of active ingredients and multi-target properties, opening up new avenues for the discovery and development of antimicrobial drugs. This study focuses on assessing the efficacy of the Shensheng-Piwen changed medicinal powder (SPC) extracts against opportunistic pathogen infections by broth microdilution and agar disc diffusion methods. Additionally, biofilm inhibition and eradication assays were performed to evaluate the antibiofilm effects of SPC extracts. Metabolite profiles were analyzed by LC-MS. Furthermore, the potential synergistic effect between SPC and Metal-Organic Framework (MOF) was investigated by bacterial growth curve analysis. The results indicated that the SPC extracts exhibited antibacterial activity against S. aureus, with a minimum inhibitory concentration (MIC) of 7.8 mg/mL (crude drug concentration). Notably, at 1/2 MIC, the SPC extracts significantly inhibited biofilm formation, with over 80% inhibition, which was critical in tackling chronic and hospital-acquired infections. Metabolomic analysis of S. aureus revealed that SPC extracts induced a notable reduction in the levels of various metabolites, including L-proline, L-asparagine. This suggested that the SPC extracts could interfere with the metabolism of S. aureus. Meanwhile, the growth curve experiment proved that SPC extracts and MOFs had a synergistic antibacterial effect. In conclusion, the present study highlights the potential of SPC extracts as a novel antibacterial agent against S. aureus infections, with promising biofilm inhibition properties. The observed synergistic effect between SPC extracts and MOFs further supports the exploration of this combination as an alternative treatment approach.

Effect of Essential oil and Extracts of Artemisia Herba – Alba Plant Against Some E Pathogenic Bacteria

Artemisia Herba – Alba is the one of the most important genus of Asteraceae family. It has numerous values because of medicine properties. Artemisia Herba – Alba has numerous application in traditional medicine from ancient times. In this research, antimicrobial effects of leaf aqueous, alcoholic extracts and essential oil of Artemisia Herba – Alba against Staphylococcus aureus PTCC 1431 and Escherichia coli PTCC 1399 were studied, using agar disc diffusion method. Methanol and ethanol extracts obtained from leaves of A. Herba – Alba exhibited antimicrobial activity against test microorganisms. In addition Artemisia herba-alba essential oil was inhibitory effects against all studied pathogenic bacteria. The results showed that essential oil of Artemisia herba-alba had the most inhibition diameter zone in Staphylococcus aureusthan E.coli (25-17mm successively). Therefore in this research we showed that the positive gram bacteria are more sensitive than negative gram bacteria. our results indicate the possibility of using essential oil in the treatment of bacterial infections, and the results of this study was encouraging, despite the need for clinical studies to determine of the real effectiveness and potential toxic effects in vivo

Biogenic synthesis of copper oxide nanoparticles using Clausena anisata leaf and Euphorbia abyssinica bark extracts and its comparative study of antibacterial activities

Green synthesis of metallic oxide nanoparticles has been used and preferred over physical and chemical methods of synthesis since it is a simple, inexpensive, and environmentally friendly method. This study aims to synthesize copper oxide nanoparticles that were successfully synthesized using Clausena anisata leaf and Euphorbia abyssinica bark by using copper sulphate pentahydrate (CuSO4·5H2O) as a precursor. The copper oxide nanoparticles were synthesized by using 2.5 mL of Clausena anisata leaf and the same amount of Euphorbia abyssinica bark extracts in 10 mL of a 15 mM CuSO4·5H2O solution using the green method. The synthesized copper oxide nanoparticles have been characterized by ultraviolet–visible (UV–Vis) absorption spectra, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The formation of copper oxide nanoparticles was confirmed by the UV–visible absorption spectrum in an intense surface plasmon resonance between 330 and 370 nm, which revealed the formation of copper oxide nanoparticles (CuO NPs). X-ray diffraction (XRD) spectra indicated the crystalline nature of CuO NPs. The average crystalline size of CuO NPs synthesized from Clausena anisata and Euphorbia abyssinica is 47.15 and 19.34 nm, respectively. The FT-IR results showed the existence of bioactive functional groups required for the reduction of copper ions, whereas the results of SEM confirm the green synthesized CuO NPs are spherical in shape. For antibacterial activity studies, the agar disk diffusion method was used. Anti-bacterial activities were studied against three different bacteria: Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Enterobacter cloacae) using CuO NPs (100–12.5 mg/mL). Ciprofloxacin and dimethyl sulphoxide, were used as positive and negative controls, respectively. Ciprofloxacin (60 µg/mL) inhibited Escherichia coli, Staphylococcus aureus, and Enterobacter cloacae with inhibition zones of 18, 20, and 25 mm, respectively. The CuO NPs synthesized from Euphorbia abyssinica bark showed higher anti-bacterial activity. Euphorbia abyssinica bark-mediated CuO NPs exhibited inhibition zones of 7, 11, and 13 mm against Escherichia coli, Enterobacter cloacae, and Staphylococcus aureus, respectively. Conversely, Clausena anisata leaf-mediated CuO NPs demonstrated inhibition zones of 8, 14, and 15 mm against the same microorganisms.

Reconciling the monodispersity of bioinspired ZnO nanoparticles on palygorskite nanorods for a well-balanced antibacterial effect and biocompatibility

In order to study the effect of support on the antibacterial activity of ZnO nanoparticles formed in the bioinspired process, a series of palygorskite (Pal) supported ZnO nanocomposites (ZnO/Pal) were fabricated using licorice extract and the antibacterial actions related to the structure of loaded ZnO nanocomposites was elucidated. The samples were characterized by the means of UV–vis, XRD, TEM, FTIR, TG and XPS, and the antibacterial properties were determined by the agar disk diffusion assay and colony counting assay. The structural analysis revealed that pure ZnO nanoparticles with average grain diameter of about 11 nm were formed in the green bioinspired process and anchored on the surface of Pal nanorods. And with Pal amount decreasing (ZnO loading increased from 10 % to 40 %), the ZnO NPs aggregated intensify and promoted the assembling of ZnO/Pal nanorods into bigger clusters, and four kinds of ZnO/Pal with different morphologies were formed. Among them, 20 % loading of ZnO/Pal showed antibacterial activity comparable to that of 30 % and better than that of 40 %, because ZnO nanoparticles in 20 % ZnO/Pal are monodispersed on Pal nanorods that maintained full exposure and high activity of ZnO NPs as well as better killing efficiency than those with clustered ZnO NPs. The mechanism analysis demonstrated that the bacteria-adsorbed capacity of Pal and the enhanced contact of small ZnO NPs with bacterial cells leading to intensified membrane-damage and intracellular metabolic imbalance are the main bactericidal actions of ZnO/Pal nanocomposites. This study first gave insight into the structure-related antibacterial behavior of ZnO/Pal nanocomposites, and provides an improved green way to design efficient clay-supported ZnO antibacterial nanomaterials.

High prevalence of multidrug-resistant Pseudomonas aeruginosa carrying integron and exoA, exoS, and exoU genes isolated from burn patients in Ahvaz, southwest Iran: A retrospective study.

Pseudomonas aeruginosa as an opportunistic pathogen produces several virulence factors. This study evaluated the relative frequency of exoenzymes (exo) A, U and S genes and integron classes (I, II, and III) among multi-drug-resistant clinical P. aeruginosa isolates from burn patients in Ahvaz, southwest of Iran. In this cross-sectional study P. aeruginosa isolates were recovered from 355 wound samples. The antimicrobial susceptibility test was done by disk agar diffusion method on Muller-Hinton agar according to the Clinical and Laboratory Standards Institute. MDR isolates were defined if they showed simultaneous resistance to 3 antibiotics. Extensively drug-resistant was defined as nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories. The presence of class I, II, and III integrons and virulence genes was determined using a PCR assay on extracted DNA. Overall, 145 clinical P. aeruginosa isolates were confirmed with biochemical and PCR tests. Overall, 35% (52/145) of the isolates were taken from males and 64% (93/145) from female hospitalized burn patients. The highest resistance rates of P. aeruginosa isolates to antibiotics were related to piperacillin 59% (n = 86/145) and piperacillin-tazobactam 57% (n = 83/145). A total of 100% of isolates were resistant to at least one antibiotic. MDR and XDR P. aeruginosa had a frequency of 60% and 29%, respectively. The prevalence of integron classes I, II, and III in P. aeruginosa was 60%, 7.58%, and 3.44%, respectively. IntI was more common in MDR and XDR P. aeruginosa isolates. In addition, 70(48%) of P. aeruginosa isolates did not harbor integron genes. Besides, exoA, exoS, and exoU in P. aeruginosa had a frequency of 55%, 55%, and 56%, respectively. It was found that P. aeruginosa as a potent pathogen with strong virulence factors and high antibiotic resistance in the health community can cause refractory diseases in burn patients.

In Vitro Evaluation of Synergistic Essential Oils Combination for Enhanced Antifungal Activity against Candida spp.

In recent years, a significant number of infections have been attributed to non-albicidal Candida species (NAC), mainly due to the increasing resistance of NAC to antifungal agents. As only a few antifungal agents are available (azoles, echinocandins, polyenes, allylamines and nucleoside analogues), it is very important to look for possible alternatives to inhibit resistant fungi. One possibility could be essential oils (EOs), which have been shown to have significant antifungal and antibacterial activity. Therefore, in this study, the efficacy of 12 EOs and their combinations was evaluated against four yeasts of the genus Candida (C. albicas, C. glabrata, C. tropicalis and C. parapsilosis). GC-MS and GC-MS FID techniques were used for the chemical analysis of all EOs. VITEK-2XL was used to determine the antifungal susceptibility of the tested Candida spp. strains. The agar disc diffusion method was used for primary screening of the efficacy of the tested EOs. The broth dilution method was used to determine the minimum inhibitory concentrations (MICs) of the most potent EOs. After MIC cultivation, the minimum fungicidal concentration (MFC) was determined on Petri dishes (60 mm). The synergistic effect of combined EOs was evaluated using the checkerboard method and expressed as a fractional inhibitory concentration index (FICI). The results showed that ginger > ho-sho > absinth > dill > fennel > star anise > and cardamom were the most effective EOs. For all Candida species tested, the synergy was mainly observed in these combinations: ginger/fennel for C. albicans FICI 0.25 and C. glabrata, C. tropicalis and C. parapsilosis FICI 0.5 and absinth/fennel for C. albicans FICI 0.3125, C. tropicalis FICI 0.3125 and C. parapsilosis FICI 0.375. Our results suggest that the resistance of fungal pathogens to available antifungals could be reduced by combining appropriate EOs.