Antibacterial Research Articles

Preparation of Alkali-Resistant Lignin Nanospheres Loaded with Silver Nanoparticles and Their Applications Toward Antibiosis and Printing.

Lignin nanoparticles (LNPs) loaded with silver nanoparticles have exhibited significant application potential in antibacterial and catalytic fields. However, the high solubility of LNPs in silver ammonia solution makes it difficult to achieve the reduction of Ag+ and the adsorption of silver nanoparticles. In this study, a protecting agent, terephthalic aldehyde (TA) is used to block lignin condensation and introduce aldehyde groups onto the lignin molecular backbone during lignin extraction. Furthermore, the TA stabilized lignin (TASL) is cross-linked with bisphenol A diglycidyl ether (BADGE) to enhance its alkali resistance performance and subsequently prepared into alkali-resistance BADGE- TASL hybrid LNPs (BADGE- TASL hy-LNPs) by anti-solvent precipitation and self-assembly. Because the presence of a large number of aldehyde groups in TASL compensates for the loss of phenolic hydroxyl groups caused by crosslinking reactions, a high loading of silver nanoparticles of 54.00% is obtained after redox reaction and adsorption in silver ammonia solution. When the BADGE-TASL hy-LNPs@Ag is used as an antibacterial agent, its inhibition efficiency reached ≈99%. Besides, the BADGE-TASL hy-LNPs@Ag can serve as a printing material for the preparation of conductive printing ink. Therefore, this study provides a strategy for lignin functionalization and application in printed electronics and antimicrobial fields.

Insights into small-molecule compound CY-158-11 antibacterial activity against Staphylococcus aureus.

The combination of the rising incidence of antibiotic resistance and the shrinking antibiotic pipeline has raised concern about the postantibiotic era. New antibacterial agents and targets are required to combat S. aureus-associated infections. In this study, we identified a maleimide-diselenide hybrid compound CY-158-11 exhibiting antibacterial activity against S. aureus in vitro and in vivo at relatively low concentrations. Furthermore, the investigation of its mode of action revealed that CY-158-11 can selectively perturb the cytoplasmic membrane of bacteria without harming mammalian cells or mouse organs. Thus, CY-158-11 is a compelling novel drug for development as a new therapy for S. aureus infections.

Cu-ZnO Embedded in a Polydopamine Shell for the Generation of Antibacterial Surgical Face Masks.

A new easy protocol to functionalize the middle layer of commercial surgical face masks (FMs) with Zn and Cu oxides is proposed in order to obtain antibacterial personal protective equipment. Zinc and copper oxides were synthesized embedded in a polydopamine (PDA) shell as potential antibacterial agents; they were analyzed by XRD and TEM, revealing, in all the cases, the formation of metal oxide nanoparticles (NPs). PDA is a natural polymer appreciated for its simple and rapid synthesis, biocompatibility, and high functionalization; it is used in this work as an organic matrix that, in addition to stabilizing NPs, also acts as a diluent in the functionalization step, decreasing the metal loading on the polypropylene (PP) surface. The functionalized middle layers of the FMs were characterized by SEM, XRD, FTIR, and TXRF and tested in their bacterial-growth-inhibiting effect against Klebsiella pneumoniae and Staphylococcus aureus. Among all functionalizing agents, Cu2O-doped-ZnO NPs enclosed in PDA shell, prepared by an ultrasound-assisted method, showed the best antibacterial effect, even at low metal loading, without changing the hydrophobicity of the FM. This approach offers a sustainable solution by prolonging FM lifespan and reducing material waste.

Study of transport, tissue distribution, depletion, and hepatotoxicity of Cyadox, a quinoxaline-1,4-dioxide derivative.

Cyadox (CYA) is a derivative of quinoxaline 1,4-dioxide and a safe and effective synthetic antibacterial agent. This study aimed to explore the drug transport in blood, distribution, depletion and hepatotoxicity of drugs in animals. The transport of CYA in blood was studied using fluorescence, circular dichroism (CD) and molecular docking methods. Tissue distribution and depletion of CYA in rats were evaluated following oral administration of [3H]-CYA at different doses. Hepatotoxicity of drugs evaluated by transcriptomics. During transport in the bloodstream, the drug binds to bovine serum albumin (BSA) by hydrogen bonding and has only one binding site. Hydrogen bonds were formed between O (2) of CYA and ARG208, O (3) of CYA and LEU480, VAL481. The secondary protein conformation of BSA changed after binding with an increase in α-helix and a decrease in β-strand. After a single oral administration of [3H]-CYA, it was excreted rapidly within 7days, with 34.81% from the urine and 60.25% from the feces. Higher and sustained levels of radioactivity were detected in the liver during the post-dose period, suggesting that the drug may concentrate in the liver. The transcriptomic data indicates that CYA exhibits low hepatotoxicity. However, there are indications that it may have an impact on steroid biosynthesis. This study could serve as a basis for conducting further studies on the use of CYA in food animals and improving the pharmacologic, pharmacokinetic, and toxicologic effects of CYA on food animals.

Optimizing the synthesis conditions of CaAl‐layered double hydroxide and poly (3‐hydroxybutyrate)/CaAl‐LDH nanocomposite for potential use in antibacterial drug delivery

AbstractCalcium aluminum layered double hydroxide (CaAl‐LDH) has gained significance for drug delivery applications due to its multiple advantages, including high drug‐loading capacity, pH sensitivity, biocompatibility, high acceptable intake values of metal ions, and its ability to provide sustained release of the intercalated drug. In this study, pristine CaAl‐LDH was synthesized by co‐precipitation method at different pH values (9 and 10) and aging times (16 and 24 h) to obtain LDH with higher d‐spacing, which is beneficial for achieving a high drug loading efficiency. Ofloxacin (OFX), an antibiotic drug, was loaded into CaAl‐LDH via regeneration (CaAl‐LDH‐OFX(RG)) and co‐precipitation (CaAl‐LDH‐OFX(CPT)) methods, and achieved drug loading of 28.3% and 36.5%, respectively. The release behavior of OFX from CaAl‐LDH‐OFX(RG) and CaAl‐LDH‐OFX(CPT) formulations was examined in simulated conditions representing the gastrointestinal tract. CaAl‐LDH‐OFX(RG) showed less initial burst release of OFX compared to CaAl‐LDH‐OFX(CPT) in acidic as well as neutral pH conditions. In order to overcome the degradation of the drug before reaching the target site, CaAl‐LDH‐OFX(RG) was reinforced at 1, 3, and 5 wt% in poly (3‐hydroxybutyrate) (PHB) matrix by sonication‐assisted solution casting method. The PHB‐based nanocomposites were characterized by XRD, FESEM, TGA, and FTIR analyses. FESEM characterization of PHB‐based films loaded with 3 wt% of CaAl‐LDH‐OFX(RG) revealed compact morphology without any aggregate formation. Moreover, PHB/3CaAl‐LDH‐OFX(RG) films demonstrated sustained release of OFX at pH 1.2 (95.60% in 96 h), pH 6.8 (78% in 113 h), and pH 7.4 (40.90% in 107 h). The promising potential of PHB‐based formulations for antibacterial drug delivery systems was confirmed by their significant antibacterial activity against Escherichia coli and Staphylococcus aureus.Highlights pH and aging time influence the structural characteristics of pristine CaAl‐LDH. Ofloxacin loaded CaAl‐LDH prepared by co‐precipitation and regeneration methods. Sustained release of ofloxacin from poly (3‐hydroxybutyrate)‐based formulation. Poly (3‐hydroxybutyrate)‐based formulations exhibit excellent antibacterial activity.

Design, synthesis and evaluation of novel LpxC inhibitors containing a hydrazone moiety as Gram-negative antibacterial agents

LpxC inhibitors are new-type antibacterial agents developed in the last twenty years, mainly against Gram-negative bacteria infections. To enable the development of novel LpxC inhibitors with potent antibacterial activities, several series of compounds were designed and synthesized and their antibacterial activities were evaluated against E. coli ATCC25922, P. aeruginosa ATCC27853, P. aeruginosa clinical isolate PAE 22-1, K. pneumoniae ATCC700603, K. pneumoniae clinical isolate KPN+22-1 in vitro. Compound 6i exhibited significant antibacterial activities against above five Gram-negative bacteria except P. aeruginosa ATCC27853. Moreover, compound 6i exhibited moderate liver microsomal stability and a promising pharmacokinetic profile (AUC0-t = 1050 ng h mL−1, oral bioavailability of 13.3 %) in Sprague-Dawley rats, acceptable PPB, low risk of drug-drug interactions and non-cytotoxic activity against hepatic cell. Collectively, compound 6i could be a promising Gram-negative antibacterial agent for further investigation.

SHIN-2 exerts potent activity against VanA-type vancomycin-resistant Enterococcus faecium in vitro by stabilizing the active site loop of serine hydroxymethyltransferase

Novel classes of antibiotics are needed to improve the resilience of the healthcare system to antimicrobial resistance (AMR), including vancomycin resistance. vanA gene cluster is a cause of vancomycin resistance. This gene cluster is transferred and spreads vancomycin resistance from Enterococcus spp. to Staphylococcus aureus. Therefore, novel antibacterial agents are required to combat AMR, including vanA-type vancomycin resistance. Serine hydroxymethyltransferase (SHMT) is a key target of antibacterial agents. However, the specific binding mechanisms of SHMT inhibitors remain unclear. Detailed structural information will contribute to understanding these mechanisms. In this study, we found that (+)–SHIN–2, the first in vivo active inhibitor of human SHMT, is strongly bound to the Enterococcus faecium SHMT (efmSHMT). Comparison of the crystal structures of apo- and (+)–SHIN–2-boud efmSHMT revealed that (+)–SHIN–2 stabilized the active site loop of efmSHMT via hydrogen bonds, which are critical for efmSHMT inhibition. Additionally, (+)–SHIN–2 formed hydrogen bonds with serine, forming the Schiff's base with pyridoxal 5′-phosphate, which is a co-factor of SHMT. Furthermore, (+)–SHIN–2 exerted biostatic effects on vancomycin-susceptible and vanA-type vancomycin-resistant E. faecium in vitro, indicating that SHMT inhibitors do not induce cross-resistance to vanA-type vancomycin. Overall, these findings can aid in the design of novel SHMT inhibitors to combat AMR, including vancomycin resistance.

Daily defined dose-costs have a stronger influence on antibacterial drug prescriptions in Germany than bacterial resistance: economic factors are more important than scientific evidence

AbstractPrevious research from our group revealed a strong association between daily defined dose (DDD)-costs and -prescriptions of antibacterial drugs in Germany (https://pubmed.ncbi.nlm.nih.gov/38842562/; https://pubmed.ncbi.nlm.nih.gov/39042156/). These data indicate that low costs are major driver of high prescription numbers. This study examines the relationship between bacterial resistance and DDD-prescriptions of antibacterial drugs using data from the Arzneiverordnungsreport (AVR) from 2008 to 2022 and the Antibiotic Resistance Surveillance (ARS) statistics provided by the Robert Koch Institute (RKI). We hypothesized that semi-rational or irrational prescribing behavior of antibacterial drugs is evident in Germany, i.e., prescriptions are driven to a greater extents by low DDD-costs than bacterial resistance. A bivariate correlation analysis was performed to test these models. Our data point to irrational prescribing behavior for amoxicillin, cefuroxime axetil, doxycycline, nitrofurantoin, ciprofloxacin, and clarithromycin. For amoxicillin clavulanic acid and sulfamethoxazole-trimethoprim, data point to semi-rational prescribing. For no antibacterial drug, a model pointing to rational drug prescribing was found. In conclusion, our study shows that DDD-costs exert a more significant influence on DDD-prescriptions than bacterial resistance, indicating that economic factors, rather than scientific evidence, primarily drive antibacterial drug prescriptions in outpatient settings in Germany. It will be important to conduct similar studies on the prescription of antibacterial drugs in other countries. It will also be important to study the relation between DDD-costs and -prescriptions for other drug classes and assess the scientific basis for these relations.

Comprehensive Exploration of Bromophenol Derivatives: Promising Antibacterial Agents against SA and MRSA.

The incidence of treatment failure due to multidrug-resistant pathogens elevated over the years; the rate is much higher than new antibiotic drug discovery. Therefore, bromophenol derivatives as potential antibacterial agents on Staphylococcus aureus and MRSA were explored in this research via integrating chemistry, microbiology, and pharmacology to address significant knowledge gaps pertaining to the antibacterial activity of bromophenols based on their functional groups. Surprisingly, a simple molecule, 3-bromo-2,6-dihydroxyacetophenone (2), exhibited good anti-S. aureus activity and even MRSA, a drug-resistant strain. In addition, compound 2 also inhibited a common resistant pathway of pathogens, biofilm formation of S. aureus and MRSA. Moreover, the therapeutic index of 2 is up to 598, which can be viewed as highly selective and having low toxicity to human HEK-293 cells. Although these compounds displayed less effectiveness for the Gram-negative bacterium, Pseudomonas aeruginosa, they still manifested some effects on the virulence properties of P. aeruginosa, such as biofilm formation, pyocyanin production, and swarming motility. In silico analyses of the structure-activity relationship as well as ADMET properties were discussed in the end. This study shed some light on the antibacterial activities of bromophenols.

Phytochemical Analysis and Nanoparticle Formulations of Extracts Myristica fragrans Houtt Leaves as Antibacterial

Myristica fragrans Houtt leaves contain secondary metabolites such as flavonoids, terpenoids and alkaloids, which have antibacterial properties. At the nanoscale, the particles have a bigger surface contact area, resulting in increased amounts and solubility of the active chemical. This leads to a stronger antibacterial activity. This study aims to examine the influence of several chitosan variations on particle size, antibacterial properties and the form of nanoparticles produced from Myristica fragrans leaves ethanol extract. Ethanol extract was analyzed using the UV-Vis spectrophotometric method to quantify total flavonoid content. Nanoparticles were synthesized using the ionic gelation technique with several ratios of chitosan and sodium tripolyphosphate, specifically 8:1, 10:1 and 12:1. Nanoparticles were analyzed with a Particle Size Analyzer (PSA) and Scanning Electron Microscopy (SEM). Agar diffusion test for bacteria germs using a paper backer. Myristica fragrans leaves ethanol extract was 50, 40 and 30 %, while nanoparticle extract was 5, 4 and 3 %. The overall flavonoid concentration in the QE/ethanol extract was 39.7252 ± 1.9596 mg. Antibacterial test results against Staphylococcus aureus and Escherichia coli bacteria and Myristica fragrans leaves extract limit inhibition area at 30 % (13.35 mm), 40 % (13.68 mm) and 50 % (13.93 mm) for Staphylococcus aureus and 30 (13.28), 40 (13.45) and 50 % (13.81 mm) for Escherichia coli. Myristica fragrans leaves extract chitosan nanoparticles included 3 (14.70), 4 (15.30) and 5 % (15.56 mm) for Staphylococcus aureus and 3 (14.60), 4 (14.65) and 5 % (15.05 mm) for Escherichia coli. Ionic gelation can create nanoparticles of Myristica fragrans leaves ethanol extract with chitosan and sodium tripolyphosphate. Myristica fragrans leaves nanoparticle ethanol extract exhibits better antibacterial activity than ethanol extract. Increasing chitosan concentration affects particle size. The ethanol extract of Myristica fragrans nanoparticle leaves showed slightly better antibacterial activity than the ethanol extract. HIGHLIGHTS Nanoparticles of extracts and extracts have proven excellent antibacterial activity against human pathogens through paper disc diffusion method. Antibacterial test results against Staphylococcus aureus and Escherichia coli bacteria and Myristica fragrans leaves extract limit inhibition area at 30 % (13.35 mm), 40 % (13.68 mm), and 50 % (13.93 mm) for Staphylococcus aureus and 30 % (13.28 mm), 40 % (13.45 mm), and 50 % (13.81 mm) for Escherichia coli. Myristica fragrans leaves extract chitosan nanoparticles included 3 % (14.70 mm), 4 % (15.30 mm), and 5 % (15.56 mm) for Staphylococcus aureus and 3 % (14.60 mm), 4 % (14.65 mm), and 5 % (15.05 mm) for Escherichia coli. The synthesized extract nanoparticles can be used against human pathogens acts as antibacterial drugs. GRAPHICAL ABSTRACT

Antibacterial and Antibiofilm Potential of Chlorophyllin Against Streptococcus mutans In Vitro and In Silico.

Streptococcus mutans is a leading causative agent of dental caries and exerts pathogenicity by forming biofilms. Dental caries continues to be a significant public health issue worldwide, affecting an estimated 2.5 billion people, showing a 14.6% increase over the past decade. Herein, the antibacterial potential of Chlorophyllin extracted from Spinacia oleracea was evaluated against biofilm-forming S. mutans via in vitro and in silico studies. The antimicrobial activity of chlorophyllin extract against S. mutans isolates was tested using the agar well diffusion method. Chlorophyllin extract was also tested against biofilm-forming isolates of S. mutans. Chlorophyllin was docked with the antigen I/II (AgI/II) protein of S. mutans to evaluate its antimicrobial mechanism. The chemical structure and canonical SMILES format of Chlorophyllin were obtained from PubChem. Additionally, adsorption, distribution, metabolism, excretion, and toxicity (ADMET) analyses of Chlorophyllin were performed using ADMETlab 2.0 to assess its pharmacokinetic properties. An agar well diffusion assay revealed that all S. mutans isolates were susceptible to Chlorophyllin extract and showed a variety of inhibition zones ranging from 32 to 41 mm. Chlorophyllin reduces the biofilm strength of four isolates from strong to moderate and six from strong to weak. The antibiofilm potential of Chlorophyllin was measured by a reduction in the number of functional groups observed in the Fourier Transform Infrared Spectrometer (FTIR) spectra of the extracellular polymeric substance (EPS) samples. Chlorophyllin showed binding with AgI/II proteins of S. mutans, which are involved in adherence to the tooth surface and initiating biofilm formation. The ADMET analysis revealed that the safety of Chlorophyllin exhibited favorable pharmacokinetic properties. Chlorophyllin stands out as a promising antibacterial and antibiofilm agent against biofilm-forming S. mutans, and its safety profile highlights its potential suitability for further investigation as a therapeutic agent.

Natural and Bioinspired Lipidic Alkynylcarbinols as Leishmanicidal, Antiplasmodial, Trypanocidal, Fungicidal, Antibacterial, and Antimycobacterial Agents.

The present review article recapitulates for the first time the antipathogenic biological data of a series of lipidic natural products and synthetic analogues thereof characterized by the presence in their structure of an alkynylcarbinol unit. The cytotoxic properties of such natural and bioinspired compounds have been covered by several literature overviews, but to date, no review article detailing their activity against pathogens has been proposed. This article thus aims at providing a comprehensive overview of the field including early studies from the 1970s and 1980s with a specific focus on results published from the late 1990s until nowadays. Publications presenting the data of almost 50 different natural products are reported. Detailed activities encompass the fields of leishmanicidal, antiplasmodial, trypanocidal, fungicidal, and mainly antibacterial and antimycobacterial compounds. The few published studies aimed at exploring the structure-activity relationship in these series are also described. Around 15 different synthetic analogues of natural products, selected among the most active reported, are also presented. The rare data available regarding the antipathogenic mode of action of these products are recalled, and finally, a comparative analysis of the available biological data is proposed with the aim of identifying the key structural determinants for the bioactivity against pathogens of these unusual compounds.

Silver Nanoparticles: A Comprehensive Review of Synthesis Methods and Chemical and Physical Properties.

Recently, silver nanoparticles (NPs) have attracted significant attention for being highly desirable nanomaterials in scientific studies as a result of their extraordinary characteristics. They are widely known as effective antibacterial agents that are capable of targeting a wide range of pathogens. Their distinct optical characteristics, such as their localized surface plasmon resonance, enlarge their utilization, particularly in the fields of biosensing and imaging. Also, the capacity to control their surface charge and modify them using biocompatible substances offers improved durability and specific interactions with biological systems. Due to their exceptional stability and minimal chemical reactivity, silver NPs are highly suitable for a diverse array of biological applications. These NPs are produced through chemical, biological, and physical processes, each of which has distinct advantages and disadvantages. Chemical and physical techniques often encounter issues with complicated purification, reactive substances, and excessive energy usage. However, eco-friendly biological approaches exist, even though they require longer processing times. A key factor affecting the stability, size distribution, and purity of the NPs is the synthesis process selected. This review focuses on how essential it is to choose the appropriate synthesis method in order to optimize the characteristics and use of silver NPs.

Enhanced bacterial disinfection of multi-drug resistance bacteria by PCN@AgI heterojunction under visible light irradiation

Pathogenic bacterial infections have become a continuing threat to human health over the past decade, the development of novel antibacterial agents or strategies against drug-resistance bacteria is highly desirable. Although porphyrin-based metal organic frameworks (PCN) are important photosensitizers (PSs) for photodynamic antibacterial treatments, they are inefficient for killing gram-negative bacteria such as Escherichia coli. Herein, PCN@AgI heterojunction was prepared as a novel and potent multifunctional antibacterial agent to combat bacteria including drug-resistance bacteria such as extended-spectrum β-lactamaseEscherichia coli (ESBL) under visible light irradiation in vitro, attributing to the cooperation of the generated ROS and released Ag+ as well as GSH-depleting ability. Compared to pristine PCN, the formation of heterojunction between AgI and PCN facilitated the sufficient separation of the produced electron- hole pairs, leading to enhanced photocatalytic antibacterial capability by producing sufficient ROS. Furthermore, its GSH-depleting ability due to its oxidase-like behavior further boosted its antibacterial capability. Significantly, in vivo studies demonstrated that PCN@AgI heterojunction could promote the healing of E. coli-infected wound on rice back with high biosafety. These findings manifested that PCN@AgI heterojunction was a good potential antibacterial therapeutic agent and may hold promise in bacteria-infected wound healing.

Highly efficient and broad-spectrum antibacterial carbon dots combat antibiotic resistance

Bacterial infections have become a major global public health issue, particularly with the emergence of multidrug-resistant strains. Therefore, developing non-antibiotic antimicrobial agents is crucial for treating drug-resistant bacterial infections. Building on previous research into natural products as novel antibacterial agents, this study synthesized curcumin-derived carbon dots using curcumin and ethylenediamine as raw materials through a hydrothermal method. The resulting carbon dots not only improved the water solubility and stability of curcumin but also exhibited highly efficient broad-spectrum antibacterial activity. Detailed investigations into the antibacterial performance and mechanisms of the carbon dots were conducted through experiments such as minimum inhibitory concentration (MIC) determination, live/dead bacterial staining, morphological studies, nucleic acid concentration detection, and reactive oxygen species (ROS) detection. The results indicated that the carbon dots significantly damaged the structural integrity of bacteria and generated large amounts of ROS. They exhibited remarkable antibacterial effects against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, and effectively inhibited drug-resistant MRSA. Their antibacterial efficacy was notably superior to that of broad-spectrum antibiotics such as chloramphenicol and Sulfadiazine. This study highlights the potential application of curcumin-derived carbon dots in combating bacterial infections and provides valuable insights for developing novel antibacterial agents derived from natural products.

Discovery of thiourea based acetylcholinesterase inhibitors and antibacterial agents: Synthesis, in vitro, structure-activity relationship and in silico study

In current work, we have synthesized a novel class of compounds (1-6) and assessed their acetylcholinesterase and antibacterial investigations to find out the most potent analogs. In this series, only two analogs were found to be the most potent against acetylcholinesterase and antibacterial activity. Analog (1, 25.35 ± 0.21 µM for acetylcholinesterase, ZOI 18.167 ± 0.7638 mm & MIC 149 μg/cm3 for antibacterial) & (6, 45.81 ± 0.02 µM acetylcholinesterase, ZOI 13.10 ± 0.5568 mm & MIC 180 μg/cm3 for antibacterial) shown to be the highest activity against both of them. In order to investigate the binding affinity of active residue molecular docking study. While the docking score energy for compounds 5, and 6 were the highest ones obtained for compound 5 was -8.2214 kcal/mol with an RMDS refine of 1.5843, while compound 6 was -8.0047 kcal/mol, with an RMDS refine of 1.3806.All of the above results confirm the analogue 5 & 6 are index as more potent than the others. Furthermore, all of the synthesized are characterized through modern spectroscopic techniques such as NMR and FTIR. In the future these are further assessed their cytotoxic effects and many more.

Preparation of Nano-Sized Eucalyptus Leaves Extract and its Application on Cotton as Natural Dyes and Antibacterial Agents

Nano-emulsions of Eucalyptus globulus leaves extract in 96% ethanol and 96% methanol were successfully prepared using the method of homogenization at various speeds of 13,000 rpm, 15,000 rpm and 17,000 rpm, with the addition of non-ionic surfactant to prevent agglomeration. A phytochemical analysis showed the presence of tannin, phenol and flavonoids. The size of the resulting nano-emulsions was measured using a particle size analyser (PSA) prior to the dyeing of cotton fabrics using the two-dips-two-nips method. Antibacterial tests were carried out on the extracts and dyed fabrics. The results showed that nano-sized particles (< 100 nm) were obtained from all extracts in both solvents used at all speeds. All dyed fabrics showed good levelness in a pale-brown colour with K/S values < 1 for all samples under spectrophotometric measurement. The colour fastness of the dyed fabrics to washing and rubbing were good to very good, with grey scale values ranging between 4/5–5. Antibacterial tests in Staphylococcus aureus bacterium showed that the eucalyptus leaves extract solution exhibited antibacterial ability, as evidenced by the formation of clear zones around the wells. Much better antibacterial activity was demonstrated by the dyed fabrics. Changing the particle size to nano increased the effectiveness of the antibacterial activity of the Eucalyptus globulus. Results showed that the nano-sized eucalyptus leaves extract demonstrated a more significant antibacterial activity than dyeability.

Characterization of the novel bequatrovirus vB-BcgM and its antibacterial effects in a food matrix.

Bacteria belonging to the Bacillus cereus group are ubiquitous in nature, causing food spoilage and food poisoning cases. A bequatrovirus, vB-BcgM, belonging to the C3 cluster infecting B. cereus group members, was isolated and characterized. Its 160-kb linear dsDNA genome contains a number of replication-related coding sequences (CDSs) and displays a collinear relationship with that of the virulent phage B4, with variations in its structural and replication regions. vB-BcgM has a relatively broad host range, with the ability to infect 33.3% of the B. cereus group isolates tested, including B. cereus, B. thuringiensis, B. anthracis, B. paranthracis, B. mycoides, and B. cytotoxicus. Moreover, vB-BcgM displays efficient infection and high replication capacity. It was found that 96.5% of the virions complete the adsorption process within 5 min. The optimal multiplicity of infection (MOI) is 10-7, and the burst size is 63 plaque-forming units (PFU)/cell. This phage showed stability over a broad pH range (4-12) and at temperatures up to 70 °C. Furthermore, vB-BcgM displays significant antibacterial effects in processed food matrices (ultra-high temperature [UHT] sterilized milk [GB 25190], UHT refrigerated milk [GB 25190], pasteurized milk [GB 19645], mashed meat, and cereals) and fresh foods (lettuce, apple, and potato). The antibacterial effects were found to be dependent on the dose of viral inoculum, incubation conditions (food matrix and temperature), and time. The data indicate that vB-BcgM has good potential as an antibacterial agent.

Design, synthesis, biological evaluation and molecular docking study of thiadiazole-isatin hybrid analogues as potential anti-diabetic and anti-bacterial agents

We have synthesized thiadiazole-isatin hybrid analogues (1–20), characterized through different spectroscopic techniques such as 1HNMR, 13CNMR, HREI-MS, and evaluated against α-glucosidase and α-amylase enzymes. All analogues showed potent inhibitory potentials, having an IC50 values ranged from 22.08 ± 0.09 to 54.03 ± 0.07 μM (against α-amylase) and 19.03 ± 0.04 to 50.03 ± 0.02 μM (α-glucosidase) when compared with the standard drug acarbose (IC50 = 22.07 ± 0.02 μM for α-amylase and IC50 = 18.01 ± 0.06 μM for α-glucosidase respectively). Among the series, analogues 13 (IC50 = 19.03 ± 0.04 and 22.08 ± 0.09 μM), 12 (IC50 = 21.03 ± 0.07 and 24.03 ± 0.07 μM), and 5 (IC50 = 22.02 ± 0.03 and 26.02 ± 0.04 μM) were identified as the most active inhibitors. The structure–activity relationship was carried out, mainly associated with the nature, number, position, and electron-donating and electron-withdrawing effects of the substituent (s) on the phenyl ring. With the help of molecular docking, the binding interaction of the most active analogues within the active site of enzymes was confirmed. Almost twelve compounds were also screened for antibacterial potential, and few were found to be effective against Bacillus subtilis. All compounds were verified for cytotoxicity against the 3 T3 mouse fibroblast cell line and detected non-toxic.

Suspected poor-quality medicines in Kenya: a retrospective descriptive study of medicine quality-related complaints reports in Kenya’s pharmacovigilance database

Poor-quality, substandard and falsified, medicines pose a significant public health threat, particularly in low-middle-income countries. A retrospective study was performed on Kenya's Pharmacovigilance Electronic Reporting System (2014–2021) to characterize medicine quality-related complaints and identify associations using disproportionality analysis. A total of 2767 individual case safety reports were identified, categorized into medicines with quality defects (52.1%), suspected therapeutic failure (41.6%), and suspected adverse drug reactions (6.3%). Predominantly reported were antineoplastic agents (28.6%), antivirals (11.7%), and antibacterial agents (10.8%) potentially linked to non-adherence to good manufacturing practices, inappropriate usage and supply chain degradation. Notably, analgesics (8.2%), and medical devices (3.5%) notified had quality defects, predominantly from government health facilities (60.0%). Antineoplastic agents (20.2%) and antivirals (3.7%) were frequently reported from suspected therapeutic failures and suspected adverse drug reactions, respectively, across both private for-profit facilities (26.5%) and not-for-profit facilities (5.4%). Underreporting occurred in unlicensed health facilities (8.1%), due to unawareness and reporting challenges. Pharmacists (46.1%), and pharmaceutical technicians (11.7%) predominantly reported quality defects, while medical doctors (28.0%) reported suspected therapeutic failures. Orally administered generic medicines (76.9%) were commonly reported, with tablets (5.8%) identified as potential sources of suspected adverse drug reactions, while quality defects were notified from oral solutions, suspensions, and syrups (7.0%) and medical devices (3.9%). The COVID-19 pandemic correlated with reduced reporting possibly due to prioritization of health surveillance. This study provides valuable evidence to supporting the use of medicine quality-related complaints for proactive, targeted regulatory control of high-risk medicines on the market. This approach can be strengthened by employing standardized terminology to prioritize monitoring of commonly reported suspected poor-quality medicines for risk-based sampling and testing within the supply chain.