Ecdysteroids from the Stem Bark of Vitex doniana Sweet (Lamiaceae; ex. Verbenaceae): A Geographically Variable African Medicinal Species

Vitex doniana Sweet is an African medicinal species that is prescribed as an aqueous bark extract to be applied topically or orally to achieve anti-infective outcomes. In select regions it is also taken orally as an antimalarial agent. The aim of the current study was to explore the biological properties of V. doniana and isolated compounds in the context of pathogenic bacteria and the protozoan parasite Plasmodium falciparum. Three compounds were isolated and assigned by nuclear magnetic resonance spectroscopy as ecdysteroids: (1) 20-hydroxyecdysone, (2) turkesterone, and (3) ajugasterone C. Interestingly, two of these compounds had not previously been identified in V. doniana, providing evidence of chemical variability between regions. The bark extract and three ecdysteroids were screened for activity against a panel of pathogenic bacteria associated with skin, stomach and urinary tract infections, and the protozoan parasite P. falciparum. The crude extract of the bark inhibited all bacterial strains with MIC values of 125–250 μg.mL−1. The three isolated compounds demonstrated less activity with MIC values of 500–1000 μg.mL−1. Furthermore, no activity was observed against P. falciparum at the screening concentration of 4.8 μg.mL−1. Nevertheless, we present a hypothesis for the possible mechanism for symptomatic relief of malarial fever, which may involve reduction of prostaglandin E(1) & E(2) activity in the hypothalamus via modulation of the monoaminergic system. While further studies are required to identify all antimicrobial agents within this plant species and to determine the cytotoxicity of each of these compounds, these data suggest that the traditional application of this species as an antiseptic is valid.

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Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v11i.8693 ◽

2020 ◽

Vol 11 ◽

pp. 37-43

Author(s):

Prof. Teodora P. Popova ◽

Toshka Petrova ◽

Ignat Ignatov ◽

Stoil Karadzhov

Keyword(s):

Dietary Supplement ◽

Broad Spectrum ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Clinical Effectiveness ◽

Inhibitory Effect ◽

Diffusion Method ◽

Bacterial Strains ◽

Microbial Strains

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.

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Antimicrobial properties of actively purified secondary metabolites isolated from different marine organisms

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200730144536 ◽

2020 ◽

Vol 21 ◽

Author(s):

Nilushi Indika Bamunu Arachchige ◽

Fazlurrahman Khan ◽

Young-Mog Kim

Keyword(s):

Secondary Metabolites ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Bacterial Species ◽

Antimicrobial Properties ◽

Antimicrobial Effect ◽

Cost Effective ◽

Resistance Mechanisms ◽

Marine Organisms ◽

Antimicrobial Compounds

Background: The treatment of infection caused by pathogenic bacteria becomes one of the serious concerns globally. The failure in the treatment was found due to the exhibition of multiple resistance mechanisms against the antimicrobial agents. Emergence of resistant bacterial species has also been observed due to prolong treatment using conventional antibiotics. To combat these problems, several alternative strategies have been employed using biological and chemically synthesized compounds as antibacterial agents. Marine organisms considered as one of the potential sources for the isolation of bioactive compounds due to the easily available, cost-effective, and eco-friendly. Methods: The online search methodology was adapted for the collection of information related to the antimicrobial properties of marine-derived compounds. These compound has been isolated and purified by different purification techniques, and their structure also characterized. Furthermore, the antibacterial activities have been reported by using broth microdilution as well as disc diffusion assays. Results: The present review paper describes the antimicrobial effect of diverse secondary metabolites which are isolated and purified from the different marine organisms. The structural elucidation of each secondary metabolite has also been done in the present paper, which will help for the in silico designing of the novel and potent antimicrobial compounds. Conclusion: A thorough literature search has been made and summarizes the list of antimicrobial compounds that are isolated from both prokaryotic and eukaryotic marine organisms. The information obtained from the present paper will be helpful for the application of marine compounds as antimicrobial agents against different antibiotic-resistant human pathogenic bacteria.

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Patterns of infections and antimicrobial drugs’ prescribing among pregnant women in Saudi Arabia: a cross sectional study

Journal of Pharmaceutical Policy and Practice ◽

10.1186/s40545-020-00292-6 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Mohamed A. Baraka ◽

Lina Hussain AlLehaibi ◽

Hind Nasser AlSuwaidan ◽

Duaa Alsulaiman ◽

Md. Ashraful Islam ◽

...

Keyword(s):

Saudi Arabia ◽

Pregnant Women ◽

Antimicrobial Agents ◽

Cross Sectional Study ◽

Maternal Complications ◽

Multicenter Studies ◽

Antimicrobial Drugs ◽

Cross Sectional ◽

Categorization System ◽

Tract Infections

Abstract Background Antimicrobial agents are among the most commonly prescribed drugs in pregnancy due to the increased susceptibility to infections during pregnancy. Antimicrobials can contribute to different maternal complications. Therefore, it is important to study their patterns in prescription and utilization. The data regarding this issue is scarce in Saudi Arabia. Therefore, the aim of this study is to generate data on the antimicrobial agents that are most commonly prescribed during pregnancy as well as their indications and safety. Methods This is a retrospective study focusing on pregnant women with a known antimicrobial use at Johns Hopkins Aramco Healthcare (JHAH). The sample included 344 pregnant women with a total of 688 antimicrobial agents prescribed. Data was collected on the proportion of pregnant women who received antimicrobial agents and on the drug safety during pregnancy using the risk categorization system of the U.S. Food and Drug Administration (FDA). Results The results showed that urinary tract infections (UTIs) were the most reported (59%) infectious diseases. Around 48% of pregnant women received antimicrobial medications at some point during pregnancy. The top two antimicrobial agents based on prescription frequency were B-lactams (44.6%) and azole anti-fungals (30%). The prescribed drugs in the study were found to be from classes B, C and D under the FDA risk classification system. Conclusion The study revealed a high proportion of antimicrobials prescribed during pregnancy that might pose risks to mothers and their fetuses. Future multicenter studies are warranted to evaluate the rational prescription of antimicrobial medications during pregnancy.

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Evaluation of antibacterial, teratogenicity and antibiofilm effect of sulfated chitosans extracted from marine waste against microorganism

Journal of Bioactive and Compatible Polymers ◽

10.1177/08839115211014225 ◽

2021 ◽

pp. 088391152110142

Author(s):

Velu Gomathy ◽

Venkatesan Manigandan ◽

Narasimman Vignesh ◽

Aavula Thabitha ◽

Ramachandran Saravanan

Keyword(s):

Biofilm Formation ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Inhibitory Effect ◽

Diffusion Method ◽

Marine Litter ◽

Ionization Time ◽

Gram Positive Bacteria ◽

Mineral Components ◽

Ft Ir

Biofilms play a key role in infectious diseases, as they may form on the surface and persist after treatment with various antimicrobial agents. The Staphylococcus aureus, Klebsiella pneumoniae, S. typhimurium, P. aeruginosa, and Escherichia coli most frequently associated with medical devices. Chitosan sulphate from marine litter (SCH-MW) was extracted and the mineral components were determined using atomic absorption spectroscopy (AAS). The degree of deacetylation (DA) of SCH was predicted 50% and 33.3% in crab and shrimp waste respectively. The elucidation of the structure of the SCH-MW was portrayed using FT-IR and 1H-NMR spectroscopy. The molecular mass of SCH-MW was determined with Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF). The teratogenicity of SCH-MW was characterized by the zebrafish embryo (ZFE) model. Antimicrobial activity of SCH-MW was tested with the agar well diffusion method; the inhibitory effect of SCH-MW on biofilm formation was assessed in 96 flat well polystyrene plates. The result revealed that a low concentration of crab-sulfated chitosan inhibited bacterial growth and significantly reduced the anti-biofilm activity of gram-negative and gram-positive bacteria relatively to shrimp. It is potentially against the biofilm formation of pathogenic bacteria.

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Exploring the possibilities of infrared spectroscopy for urine sediment examination and detection of pathogenic bacteria in urinary tract infections

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-0524 ◽

2020 ◽

Vol 58 (10) ◽

pp. 1759-1767

Author(s):

Mieke Steenbeke ◽

Sander De Bruyne ◽

Jerina Boelens ◽

Matthijs Oyaert ◽

Griet Glorieux ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Urinary Tract ◽

Urinary Tract Infections ◽

Pathogenic Bacteria ◽

Agar Plate ◽

Principal Component ◽

Blood Agar Plate ◽

Urine Sediment ◽

Flight Mass Spectrometry ◽

Tract Infections

AbstractObjectivesIn this study, the possibilities of Fourier-transformed infrared spectroscopy (FTIR) for analysis of urine sediments and for detection of bacteria causing urinary tract infections (UTIs) were investigated.MethodsDried urine specimens of control subjects and patients presenting with various nephrological and urological conditions were analysed using mid-infrared spectroscopy (4,000–400 cm−1). Urine samples from patients with a UTI were inoculated on a blood agar plate. After drying of the pure bacterial colonies, FTIR was applied and compared with the results obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Chemometric data analysis was used to classify the different species.ResultsDue to the typical molecular assignments of lipids, proteins, nucleic acids and carbohydrates, FTIR was able to identify bacteria and showed promising results in the detection of proteins, lipids, white and red blood cells, as well as in the identification of crystals. Principal component analysis (PCA) allowed to differentiate between Gram-negative and Gram-positive species and soft independent modelling of class analogy (SIMCA) revealed promising classification ratios between the different pathogens.ConclusionsFTIR can be considered as a supplementary method for urine sediment examination and for detection of pathogenic bacteria in UTI.

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Designing New Antibacterial Wound Dressings: Development of a Dual Layer Cotton Material Coated with Poly(Vinyl Alcohol)_Chitosan Nanofibers Incorporating Agrimonia eupatoria L. Extract

Molecules ◽

10.3390/molecules26010083 ◽

2020 ◽

Vol 26 (1) ◽

pp. 83

Author(s):

Cláudia Mouro ◽

Colum P. Dunne ◽

Isabel C. Gouveia

Keyword(s):

Composite Material ◽

Vinyl Alcohol ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Coating Layer ◽

Wound Dressings ◽

Poly Vinyl Alcohol ◽

Microbial Invasion ◽

Layer Composite ◽

Medicinal Plant Extracts

Wounds display particular vulnerability to microbial invasion and infections by pathogenic bacteria. Therefore, to reduce the risk of wound infections, researchers have expended considerable energy on developing advanced therapeutic dressings, such as electrospun membranes containing antimicrobial agents. Among the most used antimicrobial agents, medicinal plant extracts demonstrate considerable potential for clinical use, due primarily to their efficacy allied to relatively low incidence of adverse side-effects. In this context, the present work aimed to develop a unique dual-layer composite material with enhanced antibacterial activity derived from a coating layer of Poly(vinyl alcohol) (PVA) and Chitosan (CS) containing Agrimonia eupatoria L. (AG). This novel material has properties that facilitate it being electrospun above a conventional cotton gauze bandage pre-treated with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical (TEMPO). The produced dual-layer composite material demonstrated features attractive in production of wound dressings, specifically, wettability, porosity, and swelling capacity. Moreover, antibacterial assays showed that AG-incorporated into PVA_CS’s coating layer could effectively inhibit Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth. Equally important, the cytotoxic profile of the dual-layer material in normal human dermal fibroblast (NHDF) cells demonstrated biocompatibility. In summary, these data provide initial confidence that the TEMPO-oxidized cotton/PVA_CS dressing material containing AG extract demonstrates adequate mechanical attributes for use as a wound dressing and represents a promising approach to prevention of bacterial wound contamination.

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Advances in Understanding of the Copper Homeostasis in Pseudomonas aeruginosa

International Journal of Molecular Sciences ◽

10.3390/ijms22042050 ◽

2021 ◽

Vol 22 (4) ◽

pp. 2050

Author(s):

Lukas Hofmann ◽

Melanie Hirsch ◽

Sharon Ruthstein

Keyword(s):

Pseudomonas Aeruginosa ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Efflux Pump ◽

Copper Homeostasis ◽

The United States ◽

World Health ◽

Cross Resistance ◽

Metabolism Regulation ◽

Target Sites

Thirty-five thousand people die as a result of more than 2.8 million antibiotic-resistant infections in the United States of America per year. Pseudomonas aeruginosa (P. aeruginosa) is classified a serious threat, the second-highest threat category of the U.S. Department of Health and Human Services. Among others, the World Health Organization (WHO) encourages the discovery and development of novel antibiotic classes with new targets and mechanisms of action without cross-resistance to existing classes. To find potential new target sites in pathogenic bacteria, such as P. aeruginosa, it is inevitable to fully understand the molecular mechanism of homeostasis, metabolism, regulation, growth, and resistances thereof. P. aeruginosa maintains a sophisticated copper defense cascade comprising three stages, resembling those of public safety organizations. These stages include copper scavenging, first responder, and second responder. Similar mechanisms are found in numerous pathogens. Here we compare the copper-dependent transcription regulators cueR and copRS of Escherichia coli (E. coli) and P. aeruginosa. Further, phylogenetic analysis and structural modelling of mexPQ-opmE reveal that this efflux pump is unlikely to be involved in the copper export of P. aeruginosa. Altogether, we present current understandings of the copper homeostasis in P. aeruginosa and potential new target sites for antimicrobial agents or a combinatorial drug regimen in the fight against multidrug resistant pathogens.

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Isolation and characterization of Hena1 – a novel Erwinia amylovora bacteriophage

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa070 ◽

2020 ◽

Vol 367 (9) ◽

Author(s):

Natalya V Besarab ◽

Artur E Akhremchuk ◽

Maryna A Zlatohurska ◽

Liudmyla V Romaniuk ◽

Leonid N Valentovich ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Fire Blight ◽

Antimicrobial Agents ◽

Erwinia Amylovora ◽

Gc Content ◽

Control Measures ◽

Effective Control ◽

Lytic Phage ◽

Trna Genes ◽

Isolation And Characterization

ABSTRACT Fire blight, caused by plant pathogenic bacterium Erwinia amylovora, is one of the most important diseases of Rosaceae plants. Due to the lack of effective control measures, fire blight infections pose a recurrent threat on agricultural production worldwide. Recently, bacterial viruses, or bacteriophages, have been proposed as environmentally friendly natural antimicrobial agents for fire blight control. Here, we isolated a novel bacteriophage Hena1 with activity against E. amylovora. Further analysis revealed that Hena1 is a narrow-host-range lytic phage belonging to Myoviridae family. Its genome consists of a linear 148,842 bp dsDNA (48.42% GC content) encoding 240 ORFs and 23 tRNA genes. Based on virion structure and genomic composition, Hena1 was classified as a new species of bacteriophage subfamily Vequintavirinae. The comprehensive analysis of Hena1 genome may provide further insights into evolution of bacteriophages infecting plant pathogenic bacteria.

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South Africa’s Best BARK Medicines Prescribed at the Johannesburg Muthi Markets for Skin, Gut, and Lung Infections: MIC’s and Brine Shrimp Lethality

Antibiotics ◽

10.3390/antibiotics10060681 ◽

2021 ◽

Vol 10 (6) ◽

pp. 681

Author(s):

Gugulethu P. Khumalo ◽

Nicholas J. Sadgrove ◽

Sandy F. Van Vuuren ◽

Ben-Erik Van Wyk

Keyword(s):

South Africa ◽

Brine Shrimp ◽

Bark Extract ◽

Respiratory Pathogens ◽

Medicinal Uses ◽

Brine Shrimp Lethality ◽

Sclerocarya Birrea ◽

Lung Infections ◽

Tract Infections

Indigenous trade of medicinal plants in South Africa is a multi-million-rand industry and is still highly relevant in terms of primary health care. The purpose of this study was to identify today’s most traded medicinal barks, traditionally and contemporaneously used for dermatological, gastrointestinal, and respiratory tract infections; then, to investigate the antimicrobial activity and toxicity of the respective extracts and interpret outcomes in light of pharmacokinetics. Thirty-one popularly traded medicinal barks were purchased from the Faraday and Kwa Mai-Mai markets in Johannesburg, South Africa. Information on the medicinal uses of bark-based medicines in modern commerce was recorded from randomly selected traders. The minimum inhibitory concentration (MIC) method was used for antimicrobial screening, and brine shrimp lethality was used to determine toxicity. New medicinal uses were recorded for 14 bark species. Plants demonstrating some broad-spectrum activities against tested bacteria include Elaeodendron transvaalense, Erythrina lysistemon, Garcinia livingstonei, Pterocelastrus rostratus, Rapanea melanophloeos, Schotia brachypetala, Sclerocarya birrea, and Ziziphus mucronata. The lowest MIC value of 0.004 mg/mL was observed against Staphylococcus epidermidis for a dichloromethane bark extract of E. lysistemon. The tested medicinal barks were shown to be non-toxic against the Artemia nauplii (brine shrimp) bioassay, except for a methanol extract from Trichilia emetica (69.52% mortality). Bacterial inhibition of bark extracts with minimal associated toxicity is consistent with the safety and valuable use of medicinal barks for local muthi market customers. Antimicrobial outcomes against skin and gastrointestinal pathogens are feasible because mere contact-inhibition is required in vivo; however, MIC values against respiratory pathogens require further explaining from a pharmacokinetics or pharmacodynamics perspective, particularly for ingested rather than smoked therapies.

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Measurement of Effects of Antibiotics in Bioluminescent Staphylococcus aureus RN4220

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.12.3456-3461.2001 ◽

2001 ◽

Vol 45 (12) ◽

pp. 3456-3461 ◽

Cited By ~ 22

Author(s):

Mervi Tenhami ◽

Kaisa Hakkila ◽

Matti Karp

Keyword(s):

Staphylococcus Aureus ◽

High Throughput Screening ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Light Emission ◽

Detection System ◽

Firefly Luciferase ◽

Luciferase Reporter ◽

Luciferase Expression ◽

Luciferase Reporter Gene

ABSTRACT The spread of antibiotic resistance among pathogenic bacteria is a serious threat to humans and animals. Therefore, unnecessary use should be minimized, and new antimicrobial agents with novel mechanisms of action are needed. We have developed an efficient method for measuring the action of antibiotics which is applied to a gram-positive strain,Staphylococcus aureus RN4220. The method utilizes the firefly luciferase reporter gene coupled to the metal-induciblecadA promoter in a plasmid, pTOO24. Correctly timed induction by micromolar concentrations of antimonite rapidly triggers the luciferase gene transcription and translation. This sensitizes the detection system to the action of antibiotics, and especially for transcriptional and translational inhibitors. We show the results for 11 model antibiotics with the present approach and compare them to an analytical setup with a strain where luciferase expression is under the regulation of a constitutive promoter giving only a report of metabolic inhibition. The measurement of light emission from intact living cells is shown to correlate extremely well (r = 0.99) with the conventional overnight growth inhibition measurement. Four of the antibiotics were within a 20% concentration range and four were within a 60% concentration range of the drugs tested. This approach shortens the assay time needed, and it can be performed in 1 to 4 h, depending on the sensitivity needed. Furthermore, the assay can be automatized for high-throughput screening by the pharmaceutical industry.

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