Human Pathogenic Microbes Research Articles

The antimicrobial, antibiofilm, and wound healing properties of ethyl acetate crude extract of an endophytic fungus Paecilomyces sp. (AUMC 15510) in earthworm model

The endophytic fungus Paecilomyces sp. (AUMC 15510) was isolated from healthy stem samples of the Egyptian medicinal plant Cornulaca monacantha. We used GC–MS and HPLC analysis to identify the bioactive constituents of ethyl acetate crude extract of Paecilomyces sp. (PsEAE). Six human microbial pathogens have been selected to evaluate the antimicrobial activity of PsEAE. Our data showed that the extract has significant antimicrobial activity against all tested pathogens. However, the best inhibitory effect was observed against Bacillus subtilis ATCC 6633 and Pseudomonas aeruginosa ATCC 90274 with a minimum inhibitory concentration (MIC) of 3.9 μg/ml and minimum bactericidal concentration (MBC) of 15.6 μg/ml, for both pathogens. Also, PsEAE exerts a significant inhibition on the biofilm formation of the previously mentioned pathogenic strains. In addition, we evaluated the wound healing efficiency of PsEAE on earthworms (Lumbricus castaneus) as a feasible and plausible model that mimics human skin. Interestingly, PsEAE exhibited a promising wound healing activity and enhanced wound closure. In conclusion, Paecilomyces sp. (AUMC 15510) could be a sustainable source of antimicrobial agents and a potential therapeutic target for wound management.

Toward efficient and high-fidelity metagenomic data from sub-nanogram DNA: evaluation of library preparation and decontamination methods

BackgroundShotgun metagenomic sequencing has greatly expanded the understanding of microbial communities in various biological niches. However, it is still challenging to efficiently convert sub-nanogram DNA to high-quality metagenomic libraries and obtain high-fidelity data, hindering the exploration of niches with low microbial biomass.ResultsTo cope with this challenge comprehensively, we evaluated the performance of various library preparation methods on 0.5 pg–5 ng synthetic microbial community DNA, characterized contaminants, and further applied different in silico decontamination methods. First, we discovered that whole genome amplification prior to library construction led to worse outcomes than preparing libraries directly. Among different non-WGA-based library preparation methods, we found the endonuclease-based method being generally good for different amounts of template and the tagmentation-based method showing specific advantages with 0.5 pg template, based on evaluation metrics including fidelity, proportion of designated reads, and reproducibility. The load of contaminating DNA introduced by library preparation varied from 0.01 to 15.59 pg for different kits and accounted for 0.05 to 45.97% of total reads. A considerable fraction of the contaminating reads were mapped to human commensal and pathogenic microbes, thus potentially leading to erroneous conclusions in human microbiome studies. Furthermore, the best performing in silico decontamination method in our evaluation, Decontam-either, was capable of recovering the real microbial community from libraries where contaminants accounted for less than 10% of total reads, but not from libraries with heavy and highly varied contaminants.ConclusionsThis study demonstrates that high-quality metagenomic data can be obtained from samples with sub-nanogram microbial DNA by combining appropriate library preparation and in silico decontamination methods and provides a general reference for method selection for samples with varying microbial biomass.

Evaluation of the Antimicrobial Efficacy of some Fermented Traditional Turkish Beverages with Probiotic Potentials

Turkey is a home country for a good number of fermented beverages derived from milk, cereals, fruits and vegetables, and several studies have reported the probiotic potentiality of these beverages. Probiotics, otherwise known as beneficial microorganisms possess the ability to exert antimicrobial effects, which is one of the most important selection criteria for their use in commercial products. In the current study, the antimicrobial activities of potential probiotic bacteria isolated from five fermented traditional Turkish beverages (boza, kefir, ayran, shalgam juice and hardaliye) were evaluated. The bacterial isolates were morphologically characterised and genotypically identified by 16S rRNA gene sequence analysis. The antimicrobial effects of the isolates against selected human pathogens were assessed using spot-on-the-lawn and agar well diffusion assays. 18 of the 22 strains displayed varying degrees of antagonism against the tested pathogens. Amongst the isolates, the strongest antimicrobial effects were exhibited by strains from boza, kefir and shalgam which can be attributed to their greater microbiota diversity. Strain specificity in the activities of the obtained isolates and specificity with the different indicator pathogens tested was observed. The antimicrobial effects exhibited by boza, kefir and shalgam isolates offer a promising health benefit to consumers of these fermented probiotic products.

Mycostimulator of chitinolytic activity: Thermodynamic studies and its activity against human and food-borne microbial pathogens

Chitinolytic activity and antibiosis are gaining prominence in various biotechnological fields. Dead fungal biomass (DFB) was used as a mycostimulator of chitinase production and antibiosis by Aspergillus fumigatus. The presence of DFB stimulated the synthesis of various secondary metabolites by A. fumigatus that were detected by gas chromatography-mass spectrometry analysis such as 6,8-Di-C-á-glucosylluteolin; bistrimethylsilyl N-acetyl eicosasphinga-4,11-dienine; curan-17-oic acid, 19,20-dihydroxy-, methyl ester, (19S)-; spiro[5à-androstane-3,2′-thiazolidine; retinal; Androsta-1,4-dien-3-one; Panaxydol; Costunolide; Cyclo-(glycyl-L-tyrosyl); and 2-amino ethane thiolsulfuric acid. Chitinase activity was 42.9 Units/mL with the presence DFB, where it was 10.3 Units/mL without DFB. The maximum activity of chitinase was observed at 1.5 g of dead fungal biomass, at 4 h, 50 °C and pH 6. Thermodynamic properties showed ∆H° and ∆S° values of 126 KJ mol-1 and 432 J mol-1 K-1, respectively, indicating an endothermic reaction up to 60 °C. Deviation in ∆G° values confirmed that the reaction at 10 to 20 °C is a nonspontaneous reaction, and at 30 to 60 °C the reaction has a spontaneous nature. DFB encouraged the antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Aspergillus fumigatus, Mucor circinelloides, and Candida albicans with 2.3, 2.2, 2.8, 0.8, 0.7, and 2.2 mm inhibition zones, respectively.

Green 2D simonkolleite/zinc based nanostructures for superior antimicrobial and photocatalytic applications

The problem of organic contamination in water, unfavorable microbial growth on food products and antibiotic resistance against human pathogenic microbes has piqued interest around the world. The goal of this research is to see how effective green 2D Simonkolleite/Zinc based nanostructures (SM-Zn NS) against various human pathogenic (bacterial and fungal strains) and their photo degradation activity. Fine 2D Nanosheets of SM-Zn NS were observed by field emission scanning electron microscopy (FESEM). X-ray diffraction validated the crystalline structure of SM-Zn NS. The disc diffusion method was used to demonstrate the bactericidal effect of SM-Zn NS. On various bacterial strains, including Microcuccus luteus (Ml), Basilus subtilis (Bs), Staph aureus (Ba), Basilus pumilus (Bp), E. coli, Pseudomonas aeruginosa (Pa), Staph epidermidis, and Bordetetella bronchiseptica (Bb), at different concentrations of SM-Zn NS (10 μg/mL, 20 μg/mL) and standard drug (Ciprofloxacin 1 mg/mlL). The antifungal activity of SM-Zn NS was demonstrated using the disc diffusion method. Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, and Candida albican were tested using a single concentration of SM-Zn NS 20 μg/mL and the standard drug (Terbisil) 1 mg/ml. The results showed that green SM-Zn NS have significant and higher bactericidal as well as fungicidal effects against various human pathogens. Excess Cl− concentration responsible for formation of new defect energy level due to oxygen vacancies and the formation of the heterojunction between valance band and conduction band increased the photocatalytic properties of SM-Zn NS by reducing band gap which resulted in higher photocatalytic degradation efficiency. According to the findings, green SM-Zn NS can be used effectively in environmental remediation applications, as well as can effectively address the future medical concerns.

Considerable Production of Ulvan from Ulva lactuca with Special Emphasis on Its Antimicrobial and Anti-fouling Properties

In the current study, a significant amount of ulvan was extracted from Ulva lactuca collected from Alexandria coastline, Egypt, using a simple extraction method. According to the chemical analysis, the obtained polysaccharide content is estimated to be 36.50 g/100 g with a high sulfate content of 19.72%. Physio-chemically, the FTIR analysis confirmed the presence of sulfated groups attached to the carbohydrate backbone. The GC–MS results revealed the presence of various monosaccharides with relative abundances in the order: fucopyranose (22.09%) > L-rhamnose (18.17%) > L-fucose (17.46%) > rhamnopyranose (14.29%) > mannopyranose (8.59%) > α-D-glactopyranose (7.64%) > galactopyranose (6.14%) > β-arabinopyranose (5.62%). In addition, the SEM–EDX depicted an amorphous architecture with a majority wt% for the elements of C, O, and S. The partially purified ulvan demonstrated potent antimicrobial activity against some fish and human pathogenic microbes. The inhibition zone diameter ranged from 11 to 18 mm. On the other hand, the prepared ulvan-chitosan hydrogel significantly improved the antimicrobial activity as the inhibition zone diameter ranged from 12 to 20. Moreover, when compared to the controls, the extracted ulvan demonstrated anti-fouling properties and successfully disrupted the biofilm formed on a glass slide submerged in seawater.

Evaluation of the antimicrobial and cytotoxic potential of endophytic fungi extracts from mangrove plants Rhizophora stylosa and R. mucronata

Mangrove endophytic fungi are tolerant to numerous stresses and are inevitably capable of exhibiting excellent biological activity by producing impressive numbers of metabolites with special biological functions, based on previous work on the biological potential of mangrove-derived endophytic fungi. To obtain marked antimicrobial and cytotoxic fermentation products of culturable endophytic fungi from mangrove forests, our research evaluated the antimicrobial and cytotoxic activities of crude extracts of endophytic fungi from Rhizophora stylosa and Rhizophora mucronata. Forty-six fungal isolates were cultured on four different media, namely, dextrose agar (PDA), Czapek’s agar (CZA), rice medium (RM) and grain medium (GM) and harvested by ethyl acetate solvent at 40 days. The extracts were tested for antimicrobial activity by the microdilution method against the gram-negative bacteria Pseudomonas adaceae (PA), gram-positive bacteria Enterococcus faecalis (EF), methicillin-resistant Staphylococcus aureus (MRSA) and pathogenic fungus Monilia albicans (MA). The cytotoxic activity of the extracts was evaluated by MTT assay using A549 human lung cancer cells, HeLa human cervical carcinoma cells, and HepG2 human hepatocellular cells. The results showed that rice medium could promote the secretion of antimicrobial and antitumour secondary metabolites of endophytic fungi in comparison with other cultivation media. Seventeen strains (68%) from R. stylosa exhibited inhibitory effects on indicators, especially N. protearum HHL46, which could inhibit the growth of four microbes with MIC values reaching 0.0625 mg/mL. Fifteen strains (71.4%) from R. mucronata displayed activities against human pathogenic microbes; in particular, Pestalotiopsis sp. HQD6 and N. protearum HQD5 could resist the growth of four microbes with MIC values ranging from 0.015 to 1 mg/mL. In the cytotoxicity assay, the extracts of 10 strains (40%), 9 strains (40%) and 13 strains (52%) of R. stylosa and 13 strains (61.9%), 10 strains (47.6%) and 10 strains (47.6%) of R. mucronata displayed cytotoxicity against A549, HeLa and HepG2 cancer cells with cell viability values ≤ 50%. Neopestalotiopsis protearum HHL46, Phomopsis longicolla HHL50, Botryosphaeria fusispora HQD83, Fusarium verticillioides HQD48 and Pestalotiopsis sp. HQD6 displayed significant antitumour activity with IC50 values below 20 μg/mL. These results highlighted the antimicrobial and antitumour potential of endophytic fungi from R. stylosa and R. mucronata and the possibility of exploiting their antimicrobial and cytotoxic agents.

An Overview of On-Farm Hygienic Milk Production

- The dairy sector has adopted hazard analysis of critical control points (HACCP) systems to ensure the food safety of dairy products. Through a chain management strategy, this allows for quality verification of final goods (European Commission, 2004b). Raw milk's quality and safety are critical for milk and the dairy products' safety and quality. Milk contamination with bacteria, chemical residues, and other pollutants affects the safety and quality of the products. Microbial contamination is the subject of this chapter. Salmonella spp, Listeria monocytogenes and Campylobacter jejuni are examples of human microbial pathogens discovered in raw milk. A very high microbiological quality of raw milk is essential for preventing process losses and achieving an optimum shelf life for dairy products, in addition to its importance for the public health. For example, faults in semi-hard cheeses are caused by the spore formers of butyric acid bacteria in the raw milk, and raw milk contamination with Bacillus cereus bacteria reduces the shelf life of pasteurized dairy products. Quality assurance methods for dairy farms are being created, and bacteriological structures are being used in farms bulk of raw milk payment systems, in order to guarantee that bulk tank milk has a high microbiological quality. Furthermore, dairy producers' sanitary milk production is critical for animal’s welfare and dairy industry's image. Infections of pathogenic microorganisms affect cows (e.g., udder tissue, gastrointestinal tract), resulting in lower milk production and even mortality. In conclusion, all components of the dairy production chain benefit from the management of the microbial ecology at the dairy farm, which leads to on-farm hygienic milk productions.

Plumeria alba-Mediated Green Synthesis of Silver Nanoparticles Exhibits Antimicrobial Effect and Anti-Oncogenic Activity against Glioblastoma U118 MG Cancer Cell Line.

Plumeria alba (P. alba) is a small laticiferous tree with promising medicinal properties. Green synthesis of nanoparticles is eco-friendly, cost-effective, and non-hazardous compared to chemical and physical synthesis methods. Current research aiming to synthesize silver nanoparticles (AgNPs) from the leaf extract of P. alba (P- AgNPs) has described its physiochemical and pharmacological properties in recognition of its therapeutic potential as an anticancer and antimicrobial agent. These biogenic synthesized P-AgNPs were physiochemically characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), and zeta potential analysis. Antimicrobial activity was investigated against Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Enterococcus faecalis, Bacillus subtilis, Streptococcus pneumoniae, Candida albicans, and Candida glabrata. Anticancer activity against glioblastoma U118 MG cancer lines was investigated using an MTT assay, and apoptosis activity was determined by flow cytometry. UV–visible spectroscopic analysis portrayed surface plasmon resonance at 403 nm of synthesized P-AgNPs, and FTIR suggested the presence of amines, alkanes, and phenol molecules that could be involved in reduction and capping processes during AgNPs formation. Synthesized particles were spherical in shape and poly-dispersed with an average particle size of 26.43 nm and a poly-dispersity index (PDI) of 0.25 with a zeta potential value of −24.6 mV, ensuring their stability. The lattice plane values confirm the crystalline nature as identified by XRD. These P-AgNPs exhibited potential antimicrobial activity against selected human pathogenic microbes. Additionally, the in vitro MTT assay results showed its effective anticancer activity against the glioma U118 MG cancer cell line with an IC50 value of 9.77 µg/mL AgNPs by initiating apoptosis as identified by a staining study with flow cytometric Annexin V–Fluorescein Isothiocyanate (FITC) and Propidium Iodide (PI). Thus, P. alba AgNPs can be recommended for further pharmacological and other biological research. To conclude, the current investigation developed an eco-friendly AgNPs synthesis using P. alba leaf extract with potential cytotoxic and antibacterial capacity, which can therefore be recommended as a new strategy to treat different human diseases.

Helicobacter pylori-induced reactive oxygen species direct turnover of CSN-associated STAMBPL1 and augment apoptotic cell death

Deubiquitinylases (DUBs) are central regulators of the ubiquitin system involved in protein regulation and cell signalling and are important for a variety of physiological processes. Most DUBs are cysteine proteases, and few other proteases are metalloproteases of the JAB1/MPN +/MOV34 protease family (JAMM). STAM-binding protein like 1 (STAMBPL1), a member of the JAMM family, cleaves ubiquitin bonds and has a function in regulating cell survival, Tax-mediated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and epithelial-mesenchymal transition. However, the molecular mechanism by which STAMBPL1 influences cell survival is not well defined, especially with regard to its deubiquitinylation function. Here, we show that reactive oxygen species (ROS) induced by chemotherapeutic agents or the human microbial pathogen Helicobacter pylori can induce cullin 1-RING ubiquitin ligase (CRL1) and 26S proteasome-dependent degradation STAMBPL1. Interestingly, STAMBPL1 has a direct interaction with the constitutive photomorphogenic 9 (COP9 or CSN) signalosome subunits CSN5 and CSN6. The interaction with the CSN is required for the stabilisation and function of the STAMBPL1 protein. In addition, STAMBPL1 deubiquitinylates the anti-apoptotic protein Survivin and thus ameliorates cell survival. In summary, our data reveal a previously unknown mechanism by which the deubiquitinylase STAMBPL1 and the E3 ligase CRL1 balance the level of Survivin degradation and thereby determine apoptotic cell death. In response to genotoxic stress, the degradation of STAMBPL1 augments apoptotic cell death. This new mechanism may be useful to develop therapeutic strategies targeting STAMBPL1 in tumours that have high STAMBPL1 and Survivin protein levels.

Biosynthesis of iron oxide nanoparticles from dates, characterization, and investigation of anticarcinogenic and antimicrobial properties

Nanomaterial synthesis using natural biological systems, especially plant-based green synthesis has evinced great excitement and interest. In this study, iron oxide nanomaterials were synthesized from three different varieties of date palms obtained from Srivilliputhur, Tamil Nadu, India. The extract of date palms reduced ferric chloride in solution and facilitated the formation of iron oxide nanomaterials. Phytochemical studies of the extracts obtained from all three varieties of date palms indicated the presence of phenols. The synthesized nanomaterials were characterized by UV-VIS spectroscopy, SEM, EDAX, XRD and FTIR methods. The ability of the synthesized nanomaterials to inhibit human microbial pathogens proliferation was tested in Staphylococcus sp. and Bacillus sp. by turbidity method and recorded the maximum antimicrobial property against Bacillus sp. in the iron nanomaterial synthesized from Sukhri date palm. The cytotoxic potential of the iron oxide nanomaterials was assessed against two human cancer cell lines (A-549 and MDA-MB-231) by MTT assay. The substantial cytotoxicity response was detected from the iron oxide nanomaterials made from Sukhri date palm.

Facile synthesis and characterization of ZnO nanoparticles using Abutilon indicum leaf extract: An eco-friendly nano-drug on human microbial pathogens

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using the leaf extract of Abutilon indicum and its characterization have been investigated. UV–vis, FT-IR, Micro- Raman, XRD, and SEM investigations were used to study the optical, structural, and morphological properties of produced ZnO NPs. The antimicrobial affectivity of ZnO NPs tested by well diffusion method counter to bacteria; S. aureus, E. coli and one fungal strain; C. albicans. The absorption peak of UV–vis spectrum was observed at 377 nm. FT-IR function vibration groups had proved the existence of ZnO NPs. The Micro-Raman analysis showed low and high-intensity bands of 330 and 436 cm−1 concerning ZnO NPs. The XRD configuration indicated the pure crystalline nature ZnO NPs formation with an approximate crystalline size at 27.89 nm. SEM images showed the structure of NPs to be a spherical shape with 10–30 nm. The ZnO NPs interact with bacterial cells by electrostatic interaction. It has enhanced the surface tension and generates reactive oxygen species (ROS), leading to bacterial lysis. Conveniently, synthesized ZnO NPs can be used against Gram−ve bacteria causing infectious disease in the medical field.

Antimicrobial and anti-biofilm activities of polyphenols extracted from different Saudi Arabian date cultivars against human pathogens

BackgroundMicrobial diseases have emerged as a serious threat to the healthcare system globally and also in Saudi Arabia; various diseases are associated with higher mortality and increased spreading rates. Dietary sources are often entertained to improve the immune system of the body to fight against these infections. The date fruit (Phoenix dactylifera L) is one such functional food that is less explored for its actual potentials. MethodsThe polyphenols isolated from the different cultivars of dates in Saudi Arabia (Ajwa, Safawi, Khalas, and Sukkary) was evaluated for their antibacterial, anti-fungal and anti-biofilm forming abilities. The anti-radical properties of the phenolic extract were conducted in terms of the scavenging of diphenyl-1-picrylhydrazyl radical, hydrogen peroxide radicals and ABTS radicals. The anti-inflammatory potential was analyzed in terms of lipoxygenase activity inhibition. ResultsThe phenolic compounds of different dates were spectrophotometrically estimated and cultivars such as Ajwa and Sukkary had the highest polyphenol content. It was also noteworthy that they exerted potent antibacterial activities against Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa as estimated by the least minimal inhibitory concentration (MIC) or minimal bactericidal concentration (MBC) values. Besides, these polyphenols reduced the biofilm formation by these bacterial pathogens; it is thus possible that the polyphenols from dates can be a promising antimicrobial agent against various pathogenic strains. Corroborating with these, the polyphenol extracts from different Saudi Arabian dates were found to inhibit the growth of mycelium in strains of Candida albicans and Aspergillus niger. Apart from these, the polyphenol isolates also exhibited significant anti-radical properties against different reactive radical systems. ConclusionOverall, the efficacy of phenolic compounds extracted from the dried date fruits are not only restricted to the functional food features; instead, these molecules are capable of preventing the growth of microbial pathogens of humans. Hence, it may emerge as potent antibacterial, anti-fungal and anti-biofilm forming candidates.

Enhancing recovery of bioactive compounds from Cosmos caudatus leaves via ultrasonic extraction

Cosmos caudatus (C. caudatus) is a medicinal plant that is high in bioactive compounds such as phenolics. In this study, an ultrasound extraction method was used to optimise the extraction of bioactive compounds from C. caudatus leaves. Response surface methodology (RSM) based on a Box-Behnken design (BBD) was applied to obtain the optimum extraction parameters which is solid–liquid ratio (10–30 g/mL), particle size (180–850 µm) and extraction time (20–30 min) for maximal quercitrin and total phenolic content (TPC) yields. Analysis of antimicrobial activity was performed against two human pathogenic microbes: Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by the agar well diffusion method. The optimal ultrasonic extraction condition was as follow: solvent-liquid ratio of 1:28 (g/mL), particle size of 485 µm, and duration of 30 min, respectively. Remarkably, extraction using ultrasonic method had recovered more bioactive content and antioxidant activity than the Soxhlet method. The extract also exhibited good antimicrobial activities. Due to the above findings, the ultrasonic extraction was found to be suitable to improve recovery extraction of quercitrin and TPC from C. caudatus leaves. It also opens the possibility that the plant extract can be used for functional food and antimicrobial agents in various applications.

Whole genome sequencing of colonies derived from cannabis flowers and the impact of media selection on benchmarking total yeast and mold detection tools.

Cannabis products are subjected to microbial testing for human pathogenic fungi and bacteria. These testing requirements often rely on non-specific colony forming unit (CFU/g) specifications without clarity on which medium, selection or growth times are required. We performed whole genome sequencing to assess the specificity of colony forming units (CFU) derived from three different plating media: Potato Dextrose Agar (PDA), PDA with chloramphenicol and Dichloran Rose Bengal with chloramphenicol (DRBC). Colonies were isolated from each medium type and their whole genomes sequenced to identify the diversity of microbes present on each medium selection. Fungal Internal Transcribed Spacer (ITS3) and Bacterial 16S RNA(16S) quantitative polymerase chain reactions (qPCR) were performed, to correlate these CFUs with fungi- and bacterial- specific qPCR. Each plating medium displayed a ten-fold difference in CFU counts. PDA with chloramphenicol showed the highest diversity and the highest concordance with whole genome sequencing. According to ITS3 and 16S qPCR confirmed with whole genome sequencing, DRBC under counted yeast and mold while PDA without chloramphenicol over counted CFUs due to bacterial growth without selection. Colony Forming Unit regulations lack specificity. Each medium produces significant differences in CFU counts. These are further dependent on subjective interpretation, failure to culture most microbes, and poor selection between bacteria and fungi. Given the most human pathogenic microbes found on cannabis are endophytes which culture fails to detect, molecular methods offer a solution to this long-standing quantification problem in the cannabis testing field.

Novel Strategies to Combat the Emerging Drug Resistance in Human Pathogenic Microbes.

The major health-care burden for the developing world are infectious diseases where antimicrobial agents prove to be the magical drugs to combat this. But the phenomenon of antimicrobial resistance (AMR) represents a challenging global issue, which requires to be addressed effectively. The antimicrobial treatment for the emerging multidrug-resistant bacterial (e.g. TB, Cholera) and fungal (e.g. Candidiasis) infections is very limited, and there are multiple causes and reasons responsible for the evolution of such resistance. Considering the critical issues of increasing AMR, there is an urgent requirement of the identification, development, validation, and progression of novel strategies and approaches that can easily be utilized for overcoming this serious issue. Immunotherapy represents a significant way to improve host defenses and combat the issue of antimicrobial drug resistance. Similarly, drug combination therapy represents another promising approach for reducing the evolution of resistance and enhancing the longevity of the antimicrobial agents. Bacteriophage therapy also acts as a novel therapeutic option to control the development of the multidrug resistance (MDR) phenomenon. Besides, CRISPR, an innovative genome editing technology, offers multiple applications to safeguard host defenses to overcome different resistance challenges. The novel approaches/ strategies like combination therapy, bacteriophage therapy, immunotherapy, and CRISPR/Cas discussed here presents an overview of some of the novel strategies/approaches to be adopted against the pathogenic microbes/microbial invasions along with advanced knowledge of different drug resistance mechanisms adopted by the microbial pathogens to gain resistance against different antimicrobial agents. Therefore, understanding the novel control plans/approaches and different drug resistance mechanisms will help achieve the goals of the successful development of potential antimicrobial drugs and their respective targets and eventually help curtail the problem of increasing antimicrobial drug resistance menace in various human pathogenic microbes.

Lipidation of Temporin-1CEb Derivatives as a Tool for Activity Improvement, Pros and Cons of the Approach.

The alarming raise of multi-drug resistance among human microbial pathogens makes the development of novel therapeutics a priority task. In contrast to conventional antibiotics, antimicrobial peptides (AMPs), besides evoking a broad spectrum of activity against microorganisms, could offer additional benefits, such as the ability to neutralize toxins, modulate inflammatory response, eradicate bacterial and fungal biofilms or prevent their development. The latter properties are of special interest, as most antibiotics available on the market have limited ability to diffuse through rigid structures of biofilms. Lipidation of AMPs is considered as an effective approach for enhancement of their antimicrobial potential and in vivo stability; however, it could also have undesired impact on selectivity, solubility or the aggregation state of the modified peptides. In the present work, we describe the results of structural modifications of compounds designed based on cationic antimicrobial peptides DK5 and CAR-PEG-DK5, derivatized at their N-terminal part with fatty acids with different lengths of carbon chain. The proposed modifications substantially improved antimicrobial properties of the final compounds and their effectiveness in inhibition of biofilm development as well as eradication of pre-formed 24 h old biofilms of Candida albicans and Staphylococcus aureus. The most active compounds (C5-DK5, C12-DK5 and C12-CAR-PEG-DK5) were also potent against multi-drug resistant Staphylococcus aureus USA300 strain and clinical isolates of Pseudomonas aeruginosa. Both experimental and in silico methods revealed strong correlation between the length of fatty acid attached to the peptides and their final membranolytic properties, tendency to self-assemble and cytotoxicity.

Antimicrobial properties of silver nanoparticles prepared by Acacia etbaica (Schweinf.) valve extract

Here, we employed green and very fast (clock) synthesis of silver nanoparticles (AgNPs) by means of silver nitrate and Acacia etbaica valve extract at room temperature. Transmission electron microscopy (TEM) results confirm the spherical shape and diameter (size) ranging from 6.38 ± 3.21, 10.09 ± 3.21 and 20 ± 3.21 for AeAg-1, AeAg-2 and AeAg-3, respectively. TEM results showed that size of AgNPs increase as the concentration of AgNO3 decreases due to the low concentration of bio reducing agent present in the extract. The enhanced antimicrobial activity against human pathogenic microbes was investigated by diffusion method based on zone of inhibition. The prepared AgNPs showed high specificity against the tested pathogens, namely K. pneumonia, S. typhi, S. dysenteriae, P. mirabilis, S. saprophyticus, S. aureus and C. albican with inhibition zone between 22.3 ± 2.08 mm and 11.67 ± 1.15 mm. On the other hand, the prepared AgNPs did not exhibit high specifity against E. Faecalis and P. aeruginosa. Therefore, it can be concluded that the prepared AgNPs have potential as natural antimicrobial agents against microbes with multidrug resistance.

Evaluating the effect of spaceflight on the host\u2013pathogen interaction between human intestinal epithelial cells and Salmonella Typhimurium

Spaceflight uniquely alters the physiology of both human cells and microbial pathogens, stimulating cellular and molecular changes directly relevant to infectious disease. However, the influence of this environment on host–pathogen interactions remains poorly understood. Here we report our results from the STL-IMMUNE study flown aboard Space Shuttle mission STS-131, which investigated multi-omic responses (transcriptomic, proteomic) of human intestinal epithelial cells to infection with Salmonella Typhimurium when both host and pathogen were simultaneously exposed to spaceflight. To our knowledge, this was the first in-flight infection and dual RNA-seq analysis using human cells.

Silicon nitride: a potent solid-state bioceramic inactivator of ssRNA viruses

Surface inactivation of human microbial pathogens has a long history. The Smith Papyrus (2600 ~ 2200 B.C.) described the use of copper surfaces to sterilize chest wounds and drinking water. Brass and bronze on doorknobs can discourage microbial spread in hospitals, and metal-base surface coatings are used in hygiene-sensitive environments, both as inactivators and modulators of cellular immunity. A limitation of these approaches is that the reactive oxygen radicals (ROS) generated at metal surfaces also damage human cells by oxidizing their proteins and lipids. Silicon nitride (Si3N4) is a non-oxide ceramic compound with known surface bacterial resistance. We show here that off-stoichiometric reactions at Si3N4 surfaces are also capable of inactivating different types of single-stranded RNA (ssRNA) viruses independent of whether their structure presents an envelop or not. The antiviral property of Si3N4 derives from a hydrolysis reaction at its surface and the subsequent formation of reactive nitrogen species (RNS) in doses that could be metabolized by mammalian cells but are lethal to pathogens. Real-time reverse transcription (RT)-polymerase chain reaction (PCR) tests of viral RNA and in situ Raman spectroscopy suggested that the products of Si3N4 hydrolysis directly react with viral proteins and RNA. Si3N4 may have a role in controlling human epidemics related to ssRNA mutant viruses.