Treatment Of Microbial Infections Research Articles

Antimicrobial Effect of Response Surface Optimized Pyocyanin Produced by Pseudomonas aeruginosa

Pseudomonas aeruginosa is notable for its natural bluish-green pigment production, known as pyocyanin. Researchers have credited pyocyanin as an antimicrobial agent, in addition to its other biomedical applications. This study focused on isolating Pseudomonas aeruginosa from the local environment with the ability to synthesize pyocyanin and optimize its cultural conditions for improved yield. A total of thirty-one experimental combinations of process variables using the Central Composite Design (CCD) of Response Surface Methodology (RSM) was ran to find the best conditions for the organism to make pigments. Of the fermentation media evaluated, nutrient broth supplemented with maltose was the best fermentation medium for the organism’s pyocyanin production. A regression model described the interaction between the test variables and the pyocyanin yield with an R2 value of 87.52%, indicating that the model had a satisfactory fitness level. The determined optimal conditions include a maltose concentration of 18 g/L, a pH of 6.8, an inoculum size of 2.3 mL, and an agitation speed of 120 rpm. The optimized condition resulted in a 4.12-fold increase in pyocyanin yield compared to an unoptimized condition. Pyocyanin exhibits high antimicrobial activity compared to the conventional antibiotics assessed against E. coli and Candida albicans. Our study’s findings suggest that statistical models can improve pyocyanin synthesis by Pseudomonas aeruginosa. Furthermore, this pigment has the potential to replace conventional antibiotics in the treatment of microbial infections

Single domain antibodies from camelids in the treatment of microbial infections.

Infectious diseases continue to pose significant global health challenges. In addition to the enduring burdens of ailments like malaria and HIV, the emergence of nosocomial outbreaks driven by antibiotic-resistant pathogens underscores the ongoing threats. Furthermore, recent infectious disease crises, exemplified by the Ebola and SARS-CoV-2 outbreaks, have intensified the pursuit of more effective and efficient diagnostic and therapeutic solutions. Among the promising options, antibodies have garnered significant attention due to their favorable structural characteristics and versatile applications. Notably, nanobodies (Nbs), the smallest functional single-domain antibodies of heavy-chain only antibodies produced by camelids, exhibit remarkable capabilities in stable antigen binding. They offer unique advantages such as ease of expression and modification and enhanced stability, as well as improved hydrophilicity compared to conventional antibody fragments (antigen-binding fragments (Fab) or single-chain variable fragments (scFv)) that can aggregate due to their low solubility. Nanobodies directly target antigen epitopes or can be engineered into multivalent Nbs and Nb-fusion proteins, expanding their therapeutic potential. This review is dedicated to charting the progress in Nb research, particularly those derived from camelids, and highlighting their diverse applications in treating infectious diseases, spanning both human and animal contexts.

Targeting Intracellular Bacteria with Dual Drug-loaded Lactoferrin Nanoparticles.

Treatment of microbial infections is becoming daunting because of widespread antimicrobial resistance. The treatment challenge is further exacerbated by the fact that certain infectious bacteria invade and localize within host cells, protecting the bacteria from antimicrobial treatments and the host's immune response. To survive in the intracellular niche, such bacteria deploy surface receptors similar to host cell receptors to sequester iron, an essential nutrient for their virulence, from host iron-binding proteins, in particular lactoferrin and transferrin. In this context, we aimed to target lactoferrin receptors expressed by macrophages and bacteria; as such, we prepared and characterized lactoferrin nanoparticles (Lf-NPs) loaded with a dual drug combination of antimicrobial natural alkaloids, berberine or sanguinarine, with vancomycin or imipenem. We observed increased uptake of drug-loaded Lf-NPs by differentiated THP-1 cells with up to 90% proportion of fluorescent cells, which decreased to about 60% in the presence of free lactoferrin, demonstrating the targeting ability of Lf-NPs. The encapsulated antibiotic drug cocktail efficiently cleared intracellular Staphylococcus aureus (Newman strain) compared to the free drug combinations. However, the encapsulated drugs and the free drugs alike exhibited a bacteriostatic effect against the hard-to-treat Mycobacterium abscessus (smooth variant). In conclusion, the results of this study demonstrate the potential of lactoferrin nanoparticles for the targeted delivery of antibiotic drug cocktails for the treatment of intracellular bacteria.

Detection of Nucleic Acids of the Fish Pathogen Yersinia ruckeri from Planktonic and Biofilm Samples with a CRISPR/Cas13a-Based Assay.

Yersinia ruckeri is the cause of hemorrhagic septicemia, known as enteric redmouth disease, in salmonid fish species. This bacterial pathogen can form biofilms on abiotic surfaces of aquaculture settings or even on the surfaces of the fish themselves, contributing to their persistence in the aquatic environment. Detection methods for this and other fish pathogens can be time-consuming and lack specificity and sensitivity, limiting timely monitoring, the treatment of microbial infections, and effective control of their transmission in aquaculture settings. Rapid and sensitive detection methods for nucleic acids can be crucial for an appropriate surveillance of bacterial pathogens, and the CRISPR/Cas-based assays have emerged as a good alternative since it has been proven to be a useful tool for the rapid, specific, and sensitive detection of viruses and some bacteria. In this study, we explored the capability of the CRISPR/Cas13a system (SHERLOCK) to specifically detect both DNA and RNA (gene transcripts) from planktonic and biofilm samples of the bacterial fish pathogen Y. ruckeri. The assay was designed to detect the gyrA gene and the small noncoding RNAs (sRNAs) MicA and RprA from planktonic cultures and biofilm samples prepared in marine broth. The specific crRNA designed for these gene targets included a 28 nt specific gene sequence, and a scaffold sequence necessary for Cas13-binding. For all the assays, the nucleic acids obtained from samples were previously subjected to isothermal amplification with the recombinase polymerase amplification (RPA) method and the subsequent T7 transcription of the RPA amplicons. Finally, the detection of nucleic acids of Y. ruckeri was by means of a reporter signal released by the Cas13a collateral RNA cleavage triggered upon target recognition, measured by fluorescence- or lateral-flow-based readouts. This CRISPR/Cas13a-based assay was able to specifically detect both DNA and sRNAs from the Y. ruckeri samples, and the sensitivity was comparable to that obtained with qPCR analysis, highlighting the potential applicability of this CRISPR/Cas13a-based assay for fish pathogen surveillance.

Green Synthesized Polymeric Iodophors with Thyme as Antimicrobial Agents.

Antimicrobial resistance (AMR) is a growing concern for the future of mankind. Common antibiotics fail in the treatment of microbial infections at an alarming rate. Morbidity and mortality rates increase, especially among immune-compromised populations. Medicinal plants and their essential oils, as well as iodine could be potential solutions against resistant pathogens. These natural antimicrobials abate microbial proliferation, especially in synergistic combinations. We performed a simple, one-pot synthesis to prepare our formulation with polyvinylpyrrolidone (PVP)-complexed iodine (I2), Thymus Vulgaris L. (Thyme), and Aloe Barbadensis Miller (AV). SEM/EDS, UV-vis, Raman, FTIR, and XRD analyses verified the purity, composition, and morphology of AV-PVP-Thyme-I2. We investigated the inhibitory action of the bio-formulation AV-PVP-Thyme-I2 against 10 selected reference pathogens on impregnated sterile discs, surgical sutures, cotton gauze bandages, surgical face masks, and KN95 masks. The antimicrobial properties of AV-PVP-Thyme-I2 were studied by disc diffusion methods and compared with those of the antibiotics gentamycin and nystatin. The results confirm AV-PVP-Thyme-I2 as a strong antifungal and antibacterial agent against the majority of the tested microorganisms with excellent results on cotton bandages and face masks. After storing AV-PVP-Thyme-I2 for 18 months, the inhibitory action was augmented compared to the fresh formulation. Consequently, we suggest AV-PVP-Thyme-I2 as an antimicrobial agent against wound infections and a spray-on contact killing agent.

Nanoparticles incorporated hydrogels for delivery of antimicrobial agents: developments and trends.

The prevention and treatment of microbial infections is an imminent global public health concern due to the poor antimicrobial performance of the existing antimicrobial regime and rapidly emerging antibiotic resistance in pathogenic microbes. In order to overcome these problems and effectively control bacterial infections, various new treatment modalities have been identified. To attempt this, various micro- and macro-molecular antimicrobial agents that function by microbial membrane disruption have been developed with improved antimicrobial activity and lesser resistance. Antimicrobial nanoparticle-hydrogels systems comprising antimicrobial agents (antibiotics, biological extracts, and antimicrobial peptides) loaded nanoparticles or antimicrobial nanoparticles (metal or metal oxide) constitute an important class of biomaterials for the prevention and treatment of infections. Hydrogels that incorporate nanoparticles can offer an effective strategy for delivering antimicrobial agents (or nanoparticles) in a controlled, sustained, and targeted manner. In this review, we have described an overview of recent advancements in nanoparticle-hydrogel hybrid systems for antimicrobial agent delivery. Firstly, we have provided an overview of the nanoparticle hydrogel system and discussed various advantages of these systems in biomedical and pharmaceutical applications. Thereafter, different hybrid hydrogel systems encapsulating antibacterial metal/metal oxide nanoparticles, polymeric nanoparticles, antibiotics, biological extracts, and antimicrobial peptides for controlling infections have been reviewed in detail. Finally, the challenges and future prospects of nanoparticle-hydrogel systems have been discussed.

Fabrication, characterization, and antibacterial activity of ferrite, chromite, and aluminate nanoparticles

Zn0.33Co0.33Mg0.33X2O4 nanoparticles (NPs), where X = Fe, Cr, Al and denoted by F, C, and A, were prepared by the co-precipitation method. X-ray diffraction patterns validated the formation of NPs with cubic spinel structure with the detection of small amounts of impurities in samples C (Cr2O3) and A (MgO). Transmission electron micrographs showed a nearly spherical shape for samples F and A. However, sample C revealed cubic and nearly spherical shapes. Energy-dispersive x-ray analysis ensured the presence of chemical constituents in all samples. The vibrational modes of NPs were confirmed with Fourier transform infrared spectroscopy. The direct bandgap energy values, calculated using ultraviolet-visible spectroscopy, were in the range of 2.355 and 2.967 eV for F, C, and A samples. X-ray photoelectron spectroscopy analysis confirmed the compositions as well as the valence states of all elements. Magnetic hysteresis (M–H) loops revealed a soft ferromagnetic behavior. Sample F exhibited a higher saturation magnetization, remanent magnetization, magnetic moment, and magnetic anisotropy compared to those of samples C and A. The antibacterial activity of the tested samples against four bacteria (Staphylococcus aureus, Stenotrophomonas maltophilia, Escherichia coli, and Enterococcus faecium) was determined using the broth microdilution assay, minimum bactericidal concentration (MBC), and time-kill test. The prepared NPs exhibited varying antibacterial activity due to multiple factors. These results highlighted the potential utility of the ternary ferrite, chromite, and aluminate NPs in the treatment of microbial infections, particularly multidrug-resistant bacteria.

The Role of β-Defensin 1 Against Porphyromonas gingivalis Lipopolysaccharide-Mediated Inflammation in the THP-1 Cell Line.

Introduction Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) is one of the crucial virulence factors of periodontitis. Antimicrobial peptides (AMPs) are emerging as alternatives or adjuncts to antibiotics in the treatment of microbial infections. In this study, cytotoxicity, anti-inflammatory activity, anti-oxidative stress, cell cycle analysis, and apoptosis properties of AMP, β-defensin 1, were studied in Pg-LPS-stimulated THP-1 (Tohoku Hospital Pediatrics - 1) cell line. Methods The cytotoxic nature of Pg-LPS and β-defensin 1 was studied by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. The cytotoxic effect of β-defensin 1 on Pg-LPS-stimulated THP-1 cells was also studied by the same method. The anti-inflammatory role of β-defensin 1 against cyclooxygenase (COX), lipoxygenase (LOX), myeloperoxidase (MPO), and inducible nitric oxide synthase activities were studied. The anti-oxidative nature of β-defensin 1 was analyzed by measuring reactive oxygen species (ROS) generation by dichlorodihydrofluorescein diacetate (DCFDA) assay. Cell cycle distribution and apoptosis were studied by flow cytometry. The hemolytic nature of β-defensin 1 was predicted using the HemoPred web tool. Results The results of the study demonstrated that Pg-LPS showed dose-dependent cytotoxicity to THP-1 cells. β-Defensin 1 had dose-dependent cytotoxicity to THP-1 cells and showed a protective effect on THP-cells up to 1 µg/mL of Pg-LPS, beyond which cell viability decreased. β-Defensin 1 inhibited COX, LOX, MPO, and inducible nitric oxide synthase activities in a concentration-dependent manner. β-Defensin 1 showed anti-oxidative activity by suppressing the generation of ROS measured through fluorescence intensity. From the cell cycle analysis, it was found that β-defensin 1 was able to reduce the Pg-LPS-induced cell cycle arrest at the G0/G1 phase. From the apoptosis profile, β-defensin 1 was found to increase the live cells when compared to THP-1 cells stimulated only with Pg-LPS, indicating that β-defensin 1 provided a protective role to THP-1 cells. β-Defensin 1 was found to be hemolytic in nature by the HemoPred web tool. Conclusion β-Defensin 1 exerted multifunctional activities and can be considered a promising agent for controlling periodontitis.

Analysis of Phytoconstituents and Antimicrobial Properties of Bacopa monnieri (L.) Against Clinical Pathogen

There are numerous therapeutic uses for medicinal plants in treating and managing numerous diseases. Traditional medicinal plantswere mostly needed in the current scenario. The world's warmer and wetlands regions are home to the medicinal herb Bacopa monnieri (L.).It has been utilized for ages in Ayurvedic systems. The Bacopa monnieri was one of the traditional medicinal plants. These are commonlycalled "Brahmi," and the Tamil vernacular name is "Neerbrahmmi." It is easy to cultivate and grow in all seasons. These peculiar activeingredients, also known as memory enhancement and phytoconstituents were enriched in this medicinal plant. The present study focused onanalyzing phytoconstituents and the antimicrobial activity of Bacopa monnieri leaves. The efficacy of phytoconstituents on the antimicrobialactivities concerning minimum inhibitory concentrations was performed with different polar and non-polar solvents of the respective plant.The phytoconstituents such as alkaloids, amino acids, coumarins, flavonoids, glycosides, phenols, phlobatannins, quinones, reducing sugars,saponins, steroids, tannins, and terpenoids were recorded, respectively. Antibacterial activity performed with following human clinicalbacteria like Clostridium butyricum, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae, and the antifungal activity against humanclinical such as Aspergillus flavus, A.niger, Aspergillus sp., and Penicillium sp. were determined. Among the two solvent extractions, the aqueousextract showed a more significant result than the benzene extract. According to the MIC, the antimicrobial properties of B.monnieriwithdifferent extracts were analyzed. The very minimum concentration has shown better inhibitions against microbes. The present study exploredthe antimicrobial properties of human clinical pathogens. So, the B.monnieriaqueous extract of leaves was suggested for the treatment ofmicrobial infections.

Isolation of Biomolecules from the Leaves of Lecaniodiscus cupanoides (Sapindaceae), a Plant used in Traditional Medicine in Benin

The aim of the present study was to identify the structure of the bioactive molecules in the active ethyl acetate fraction of the hydroethanolic extract of Lecaniodiscus cupanoides (Sapindaceae), a Beninese plant used in the treatment of microbial infections. We prepared the hydroethanolic extract from powdered dried leaves. We fractionated the hydroethanol extract using the liquid-liquid extraction method with solvents of increasing polarity. The active ethyl acetate fraction obtained after bioguided fractionation of the hydroethanol extract on bacterial strains was purified by a series of atmospheric pressure column chromatographic methods coupled with thin layer chromatography. At the end of this purification process, three compounds, including a flavonoid and two fatty acids, were isolated and identified by interpretation of 1H NMR, 13C NMR and mass spectrometry spectra. These were: 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dihydrochromen-4-one;(E)-3-(3,4-dihydroxyphenyl)-2-(3-(3,4-dihydroxyphenyl) acryloyloxy) propanoic acid and (E)octadec -9- enoic acid (oleic acid).
 The added value of this work lies in the fact that these three molecules have never before been identified in this plant, and therefore represent a potential avenue for the development of a therapeutic arsenal to combat microbial infections.

AMPpred-MFA: An Interpretable Antimicrobial Peptide Predictor with a Stacking Architecture, Multiple Features, and Multihead Attention.

Antimicrobial peptides (AMPs) are small molecular polypeptides that can be widely used in the prevention and treatment of microbial infections. Although many computational models have been proposed to help identify AMPs, a high-performance and interpretable model is still lacking. In this study, new benchmark data sets are collected and processed, and a stacking deep architecture named AMPpred-MFA is carefully designed to discover and identify AMPs. Multiple features and a multihead attention mechanism are utilized on the basis of a bidirectional long short-term memory (LSTM) network and a convolutional neural network (CNN). The effectiveness of AMPpred-MFA is verified through five independent tests conducted in batches. Experimental results show that AMPpred-MFA achieves a state-of-the-art performance. The visualization interpretability analyses and ablation experiments offer a further understanding of the model behavior and performance, validating the importance of our feature representation and stacking architecture, especially the multihead attention mechanism. Therefore, AMPpred-MFA can be considered a reliable and efficient approach to understanding and predicting AMPs.

In-Vivo Bactericidal Potential of Mangifera indica Mediated Silver Nanoparticles against Aeromonas hydrophila in Cirrhinus mrigala.

The present study reports the green synthesis of silver nanoparticles from leaves' extract of Mangifera indica (M. indica) and their antibacterial efficacy against Aeromonas hydrophila (A. hydrophila) in Cirrhinus mrigala (C. mrigala). The prepared M. indica mediated silver nanoparticles (Mi-AgNPs) were found to be polycrystalline in nature, spherical in shapes with average size of 62 ± 13 nm. C. mrigala (n = ±15/group) were divided into six groups i.e., G1: control, G2: A. hydrophila challenged, G3: A. hydrophila challenged + Mi-AgNPs (0.01 mg/L), G4: A. hydrophila challenged + Mi-AgNPs (0.05 mg/L), G5: A. hydrophila challenged + Mi-AgNPs (0.1 mg/L) and G6: A. hydrophila challenged + M. indica extract (0.1 mg/L). Serum biochemical, hematological, histological and oxidative biomarkers were evaluated after 15 days of treatment. The liver enzyme activities, serum proteins, hematological parameters and oxidative stress markers were found to be altered in the challenged fish but showed retrieval effects with Mi-AgNPs treatment. The histological analysis of liver, gills and kidney of the challenged fish also showed regaining effects following Mi-AgNPs treatment. A CFU assay from muscle tissue provided quantitative data that Mi-AgNPs can hinder the bacterial proliferation in challenged fish. The findings of this work suggest that M. indica based silver nanoparticles can be promising candidates for the control and treatment of microbial infections in aquaculture.

Antibacterial potential and modes of action of botanicals from Momordica foetida (Cucurbitaceae) against multidrug-resistant bacteria expressing active efflux pumps

Background: Momordica foetida (cucurbitaceae) known as a bitter cucumber in Cameroon is used as a medicinal plant. This plant is widely used in the treatment of microbial infections, diabetes, hypertension, stomach, and intestinal irritation. The leaves are also used to treat malaria, earache, and toothache. This study aimed at investigating the antibacterial activity of the methanol extract of M. foetida seeds against multidrug-resistant bacteria expressing active efflux pumps and to characterize the mode of action of this extract. Methods: The antibacterial activity of the crude extract of M. foetida in the presence and absence of an efflux pump inhibitor, phenylalanine-arginine β-naphthylamide (PAβN), was evaluated by the serial micro-dilution method. The determination of the effect of this sample on bacterial H+-ATPase proton pumps was performed by a standard method using a pH meter and the study of the effect of the same sample on cell growth kinetics, bacterial membrane, and biofilms was performed by a spectrophotometric method. Results: The phytochemical composition of the crude extract of M. foetida, evaluated using standard qualitative methods, showed a rather selective distribution of secondary metabolites (presence of polyphenols, flavonoids, alkaloids, triterpenes, sterols, and saponins). The crude extract of this plant virtually inhibited the growth of 90.90% (20/22) of the bacteria studied with minimal inhibitory concentrations (MIC) ranging from 64 to 1024 µg/mL. The lowest MIC of 64 µg/mL was observed against Escherichia coli (AG102, MC4100, W3110), Klebsiella pneumoniae (KP55 and ATCC 11296), Providencia stuartii (NEA16, ATCC 29916 and PS2636), Pseudomonas aeruginosa (PA124) and Staphylococcus aureus (MRSA9) strains. In the presence of PAβN, the activity of the extract was increased against all strains and isolates used. The crude extract caused a prolongation of the lag phase and a general decrease in the growth of Escherichia coli AG102 bacteria due to the blocking of the H+-ATPase proton pumps of this bacterium, resulting in a decrease in the acidity of the medium. This sample destroyed the bacterial membrane and showed significant activity on the biofilms of this strain tested. Conclusion: The results obtained in the present work provide important and significant data that could allow the probable use of Momordica foetida in the control of bacterial infections.

A REVIEW ON ANTIVIRAL PLANTS EFFECTIVE AGAINST DIFFERENT VIRUS TYPES

The treatment of microbial infections has proven challenging for humans in recent years. Synthetic medications, such as antimicrobial agents, are used for treating these infections. Antimicrobials derived from natural sources have gained popularity as an alternative to manufactured medications due to their lack of adverse effects. Plants, which play a significant role in this setting, have historically served as a reliable natural defence against several pathogens. In this study, studies on plants used against viral diseases are mentioned. Studies on viruses that cause disease have been compiled in the literature. According to the findings, it has been reported in the literature that many different plant species are effective against herpes simplex virus (HSV-1, HSV-2), human immunodeficiency virus (HIV), influenza virus (A, B) and parainfluenza, Poliovirus, Astrovirus, Parvovirus, Sindbis virus (SINV), Feline calicivirus (FCV), Rhinovirus, Echovirus, Rotavirus, Bovine alphaherpesvirus 1 (BoHV-1), Reovirus, Vaccinia virus (VACV), Cardiovirus A (Encephalomyocarditis virus; EMCV), Coxsackie virus, Semliki forest, Measles virus, Newcastle disease virus (NDV), Coronavirus, Adenovirus (ADV-3, ADV-5, ADV-8, ADV -11), Canine distemper virus (CDV), Lumpy skin disease virus (LSDV), Hepatitis A, B, C virus and Enterovirus. To combat viruses, plants can be considered a potentially invaluable natural resource.

Liposomal Antibiotics for the Treatment of Infectious Diseases

Liposomal delivery systems have been utilized in developing effective therapeutics against cancer and targeting microorganisms in and out of host cells and within biofilm community. The most attractive feature of liposome-based drugs are enhancing therapeutic index of the new or existing drugs while minimizing their adverse effects. This communication provides an overview on several aspects of liposomal antibiotics including the most widely used preparation techniques for encapsulating different agents and the most important characteristic parameters applied for examining shape, size and stability of the spherical vesicles. In addition, the routes of administration, liposome--cell interactions and host parameters affecting the bio distribution of liposomes are highlighted. Liposomes are safe and suitable for delivery of variety of molecules and drugs in biomedical research and medicine. They are known to improve the therapeutic index of encapsulated agents and reduce drug toxic- ity. Recent studies on liposomal formulation of chemotherapeutic and bioac- tive agents and their targeted delivery show liposomal antibiotics potential in the treatment of microbial infections.

A longitudinal study reveals persistence of antimicrobial resistance on livestock farms is not due to antimicrobial usage alone.

There are concerns that antimicrobial usage (AMU) is driving an increase in multi-drug resistant (MDR) bacteria so treatment of microbial infections is becoming harder in humans and animals. The aim of this study was to evaluate factors, including usage, that affect antimicrobial resistance (AMR) on farm over time. A population of 14 cattle, sheep and pig farms within a defined area of England were sampled three times over a year to collect data on AMR in faecal Enterobacterales flora; AMU; and husbandry or management practices. Ten pooled samples were collected at each visit, with each comprising of 10 pinches of fresh faeces. Up to 14 isolates per visit were whole genome sequenced to determine presence of AMR genes. Sheep farms had very low AMU in comparison to the other species and very few sheep isolates were genotypically resistant at any time point. AMR genes were detected persistently across pig farms at all visits, even on farms with low AMU, whereas AMR bacteria was consistently lower on cattle farms than pigs, even for those with comparably high AMU. MDR bacteria was also more commonly detected on pig farms than any other livestock species. The results may be explained by a complex combination of factors on pig farms including historic AMU; co-selection of AMR bacteria; variation in amounts of antimicrobials used between visits; potential persistence in environmental reservoirs of AMR bacteria; or importation of pigs with AMR microbiota from supplying farms. Pig farms may also be at increased risk of AMR due to the greater use of oral routes of group antimicrobial treatment, which were less targeted than cattle treatments; the latter mostly administered to individual animals. Also, farms which exhibited either increasing or decreasing trends of AMR across the study did not have corresponding trends in their AMU. Therefore, our results suggest that factors other than AMU on individual farms are important for persistence of AMR bacteria on farms, which may be operating at the farm and livestock species level.

Lindera Essential Oils from Vietnam: Antimicrobial Activity and Constituents of the Leaf of Lindera chunii Merr. (Lauraceae) Essential Oils and Chemotaxonomy

Lindera chunii Merr. is an important member of the Lauraceae family of plants which are known for their medicinal values. In this research article, the chemical constituents and antimicrobial activity of essential oils from the leaves of L. chunii grown in Vietnam were reported. The essential oil was obtained by hydrodistillation of the leaves of L. chunii while the constituents were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated using a microdilution broth susceptibility assay. The constituents occurring in higher amounts in the leaf essential oil of L. chunii were mainly the monoterpene hydrocarbons comprising terpinolene (13.0%), α-pinene (8.0%), β-pinene (7.6%), camphene (7.3%), β-phellandrene (7.1%) and myrcene (5.0%). The leaf essential oil of L. chunii inhibited the growth of Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC25923 and Salmonella enterica ATCC13076, each with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. The corresponding median lethal concentration (IC50) values were 19.45 μg/mL, 20.45 μg/mL and 18.78 μg/mL, respectively. The essential oil also displayed anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 64.0 μg/mL, and IC50 value of 23.12 μg/mL. The antimicrobial activity of L. chunii essential oil was reported for the first time as a confirmation of the traditional uses of the plant in the treatment of microbial infections. Furthermore, the paper discusses the chemotaxonomy of Lindera oil samples.

STRYCHNOS SPINOSA LAM: COMPREHENSIVE REVIEW ON ITS MEDICINAL AND NUTRITIONAL USES.

Background: Most of the people living in developing countries rely on local remedies from traditional medicines to take care of their healthcare needs. In recent years, the use of medicinal plants increased considerably. Consequently, studies on medicinal plants are necessary to produce more effective drugs with fewer side-effects. This work aims to compile the dispersal data on Strychnos spinosa Lam., a medicinal plant with great therapeutic potential in traditional medicine, on its ethnobotanical uses, chemical compounds, as well as its pharmacological and nutritional effects. Material and Methods: To achieve the aforementioned aim, electronic databases such as Pubmed, Science Direct, Google scholar, Scopus and SciFinder were scanned. Results: Literature survey revealed that S. spinosa is used in the treatment of microbial infections, malaria, trypanosomiasis, intestinal worms, tuberculosis, infertility, gastrointestinal disorders, snake bite, hypertension, and diabetes mellitus among other ailments. The plant is also used as food material. S. spinosa contains many chemical compounds, such as alkaloids, terpenes, sterols, fatty acids, flavonoids, saponin, and others. The fruits are a source of important nutrients such as carbohydrates, sugars, proteins, vitamins and fibres. Experimental studies have shown numerous pharmacological properties, including antimicrobial, antiplasmodial, anti-trypanosomal, anti-leishmanial, anti-nematicidal, anti-inflammatory, anti-oxidant, antidiabetic and other activities. Conclusion: This review article provides comprehensive information on S. spinosa and its various extracts. Due to the promising effects of the plant extracts on various diseases and its nutritional values, there is a need for toxicity studies and clinical trials to assess the effects of its identified bioactive compounds.

Inhibition of Polymicrobial Biofilms of Candida albicans-Staphylococcus aureus/Streptococcus mutans by Fucoidan-Gold Nanoparticles.

The polymicrobial proliferation and development of complex biofilm morphologies by bacterial and fungal pathogens in the host are some of the key factors contributing to the failure of antimicrobial treatments. The polymicrobial interaction of Candida albicans and some bacterial species has been extensively studied in both in vitro and in vivo model systems. Alternative strategies for disrupting polymicrobial interaction and biofilm formation are constantly needed. Among several alternative strategies, the use of nanoparticles synthesized using a natural product in the treatment of microbial infection has been considered a promising approach. The current study aimed to synthesize gold nanoparticles (AuNPs) using a natural product, fucoidan, and to test their efficacy against mono and duo combinations of fungal (Candida albicans) and bacterial (Staphylococcus aureus/Streptococcus mutans) biofilms. Several methods were used to characterize and study Fu-AuNPs, including UV-vis absorption spectroscopy, FTIR, FE-TEM, EDS, DLS, zeta potential, and XRD. The concentration-dependent inhibition of early-stage biofilms and the eradication of mature biofilms of single species of C. albicans, S. aureus, and S. mutans have been observed. Early biofilms of a dual-species combination of C. albicans and S. aureus/S. mutans were also suppressed at an increasing concentration of Fu-AuNPs. Furthermore, Fu-AuNPs significantly eradicated the established mature biofilm of mixed species. The treatment method proposed in this study, which involves the use of marine-bioinspired nanoparticles, is a promising and biocompatible agent for preventing the growth of polymicrobial biofilms of bacterial and fungal pathogens.

Advances in Liposome-Encapsulated Phthalocyanines for Photodynamic Therapy

This updated review aims to describe the current status in the development of liposome-based systems for the targeted delivery of phthalocyanines for photodynamic therapy (PDT). Although a number of other drug delivery systems (DDS) can be found in the literature and have been studied for phthalocyanines or similar photosensitizers (PSs), liposomes are by far the closest to clinical practice. PDT itself finds application not only in the selective destruction of tumour tissues or the treatment of microbial infections, but above all in aesthetic medicine. From the point of view of administration, some PSs can advantageously be delivered through the skin, but for phthalocyanines, systemic administration is more suitable. However, systemic administration places higher demands on advanced DDS, active tissue targeting and reduction of side effects. This review focuses on the already described liposomal DDS for phthalocyanines, but also describes examples of DDS used for structurally related PSs, which can be assumed to be applicable to phthalocyanines as well.