The therapeutic potential of essential oils (EOs) from Cinnamomum verum (C. verum) and Artemisia herba alba (A. herba alba) was investigated through a comprehensive analysis of their chemical composition, antioxidant, anti-inflammatory, and antibacterial activities. Gas Chromatography--Mass Spectrometry (GC-MS) analysis identified cinnamaldehyde (72.76%) as the primary component in C. verum EO and camphor (55.59%) as the major constituent in A. herba alba EO. In vitro assays revealed that C. verum EO exhibited superior antioxidant activity, with a nitric oxide (NO) scavenging activity of 85.4% at 200 µg/mL and a ferric reducing power (FRP) of 1.2 absorbance units at 700 nm, compared to A. herba alba EO, which showed 45.6% NO scavenging and 0.6 absorbance units in FRP. Both EOs displayed dose-dependent antibacterial activity against pathogenic strains, with C. verum EO showing inhibition zones of 22.5 mm and 20.3 mm against Staphylococcus aureus and Escherichia coli, respectively, while A. herba alba EO exhibited zones of 18.7 mm and 16.4 mm. In the red blood cell (RBC) H₂O₂-induced hemolysis model, C. verum EO demonstrated strong anti-inflammatory and protective effects, inhibiting hemolysis by 78.3% at 200 µg/mL, compared to 52.6% for A. herba alba EO. A 50:50 combination of the two EOs showed intermediate activity, with 65.4% inhibition of hemolysis, suggesting partial synergy. In silico ADMET analysis predicted high oral bioavailability (80-90%) and strong intestinal absorption for the major compounds, with cinnamaldehyde and camphor showing potential for brain penetration (BOILED-Egg model). Molecular docking studies revealed the strong binding affinities of δ-cadinene (ΔGb = -7.48 kcal/mol) and α-thujone (ΔGb = -4.75 kcal/mol) to key enzymes involved in inflammation, oxidative stress, and bacterial infections, supporting their multitarget therapeutic potential. These findings highlight the promising applications of C. verum and A. herba alba EOs as natural agents for combating oxidative stress, inflammation, and bacterial infections, with potential for integration into therapeutic formulations.

Bacterial infections are difficult to treat due to multi-drug resistance, a global health challenge. Plant secondary metabolites, known for their broad spectrum of biological activities, offer a promising alternative. These compounds, particularly phenolics, are recognized for their antibacterial mechanisms and their potential to enhance the efficacy of conventional antibiotics. Agrimonia eupatoria, a plant from the Rosaceae family, is rich in phenolics and demonstrates a range of bioactivities, including antibacterial activity [1]. This study aimed to evaluate the antibacterial and antibiofilm properties of a 70% ethanolic–aqueous extract of the Agrimonia eupatoria herb, as well as its cytotoxicity and bacterial selectivity to assess its safety. The microdilution assay results demonstrated the extract to be significantly active against Staphylococcus aureus, Staphylococcus aureus MRSA, Listeria monocytogenes, and Shigella flexneri, with MIC values of 0.31 mg/mL for all strains, interpreted according to the MIC classification of Tamokou et al. [2 ]. Further, crystal violet staining of the biofilm biomass demonstrated the most notable antibiofilm effect against S. aureus MRSA, with a decrease in the biofilm biomass of up to 85.40%, followed by the effects against S. aureus (63.67%) and L. monocytogenes (62.24%). An increase in the biofilm biomass was observed in S. flexneri, which could be attributed to a stress response. To evaluate the safety of the extract, the selectivity index was calculated as the ratio between the cytotoxic (IC₅₀) and antimicrobial effect (MIC). The positive values obtained showed the higher selectivity of the extract towards bacteria compared to that for normal human fetal lung fibroblasts, i.e., MRC-5 cells (IC₅₀ = 1.52 mg/mL). The obtained results show that A. eupatoria possesses antibacterial and antibiofilm activity, which supports further research into its molecular mechanisms of action and potential synergistic effects with the available antibiotics. This strategy could target different sites of the bacterial cells and the pathways involved in biofilm formation, thereby improving antibacterial activity and preventing the development of resistance.

Antimicrobial resistance (AMR) poses a critical threat to global public health. Multidrug-resistant bacteria, including A. baumannii, P. aeruginosa, and S. aureus, are major causes of hospital-acquired infections. This resistance phenomenon has also spread to parasites such as P. falciparum, the most virulent form of malaria. Therefore, new treatments targeting essential biological pathways that are not addressed by current agents are urgently needed to minimize potential cross-resistance.

Microbial fatty acid biosynthesis, relying on the fatty acid synthase system (FAS-II), is essential for microbial membrane lipid synthesis. The FAS-II enzymes, which are absent in humans, provide a selective target, minimizing the risk of off-target effects on human fatty acid synthesis. Their highly conserved active site amino acid sequences support their broad-spectrum antimicrobial potential, and the available crystal structures in the Protein Data Bank (PDB) offer an excellent opportunity for structure-based drug design. Among the FAS-II enzymes, FabZ dehydratase appears as a promising yet underexplored target in the fight against AMR.

Based on the results of Sharma et al. (2003), we demonstrated that quinoline derivatives, such as NAS91 (IC₅₀ Pf = 12 µM ; IC₅₀ PfFabZ = 7.5 µM), inhibit PfFabZ activity and suppress P. falciparum growth. Structural analyses of NAS91-PfFabZ co-crystals revealed key ligand–enzyme interactions, guiding us in the rational design of 37 new 8-arylquinolines. These compounds were evaluated in vitro against a large panel of bacteria and P. falciparum, where a first hit, 4c, stood out (IC₅₀ Pf = 13.7 µM). Additionally, their corresponding complexes with different FabZ structures available in the PDB were analyzed by means of detailed in silico studies. Here, we will present the optimized structures of new inhibitors, derived from comprehensive in vitro and in silico findings, as well as their organic synthesis. The optimized production of FabZ enzymes from H. pylori and P. falciparum, required for enzymatic assays, will also be presented.

Hospital-acquired infections (HAIs) are nosocomial infections or diseases that are contracted during medical care but were absent at admission. Usually resulting from biofilm development on device surfaces, these infections shield microorganisms and raise their resistance to antimicrobial therapies. Moreover, many infections are challenging to detect and treat, which raises morbidity, death, and medical expenses. On medical equipment, biofilms, which are dense microbial colonies surrounded by an extracellular matrix, have been reported to be a major cause of ongoing infections resistant to antibiotics and human immune responses. Up to 75% of all bacterial infections are associated with biofilms, which also significantly contribute to nosocomial infections, especially in intensive care units. Common device-associated infections include catheter-related bloodstream infections, urinary tract infections, and ventilator-associated pneumonia. Both bacterial and fungal pathogens cause these diseases; however, the multi-species biofilms of bacterial and fungal pathogens provide extra treatment difficulty. Common bacteria such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, as well as fungal pathogens like Candida albicans, can form biofilms on various devices, including catheters, prosthetic joints, and ventilators. Most of the time, traditional treatment therapies fail. Therefore, device removal and long-term antibiotic treatment become necessary. The development of new strategies for prevention and treatment, including innovative anti-adhesive coatings and nanomaterial-based techniques targeting biofilm formation stages, the application of biofilm-active antibiotics, anti-quorum sensing agents, and biofilm dispersal agents has attracted attention in recent years. Here, we discuss the latest developments in relation to several strategies, such as antimicrobial coating, surface modification, nanostructured surface and nanomaterials, and the incorporation of regulatory molecules (natural and synthetic molecules) to prevent biofilms on the surface of biomedical devices.

Antimicrobial resistance (AMR) poses a severe threat to public health and economic stability in Nigeria, contributing to the global estimate of 700,000 annual deaths, with projections of 10 million by 2050, if unaddressed. This study examines the challenges and drivers of AMR in Nigeria, alongside strategies and their outcomes. Key factors fueling AMR include public knowledge gaps, patient non-compliance, cultural misconceptions about antibiotic use, inappropriate prescribing, and irrational drug use in humans and animals. Despite institutional efforts to curb AMR through surveillance, infection control, and awareness campaigns, success has been limited due to persistent and evolving challenges. Results indicate that low public awareness and inadequate regulation enforcement continue to undermine reduction schemes, with antibiotic misuse remaining prevalent in both healthcare and agricultural settings. Compliance issues and cultural beliefs further complicate efforts, as patients often fail to complete prescribed treatments or misuse antibiotics based on misinformation.

To address these findings, this study proposes targeted recommendations. Sponsored ads and programmatic advertising during AMR Awareness Week can enhance public education, reaching diverse Nigerian demographics. Localized AMR-centered health talks at the community level, as well as the integration of foundational AMR courses into educational curricula, aim to bridge knowledge gaps. The continuous evaluation and adaptation of these strategies are critical to tackle emerging challenges effectively. While national strategies and research investments show some promises, their suboptimal impact highlights the need for innovative approaches. Implementing these recommendations could significantly reduce AMR’s burden in Nigeria, improving public health outcomes, supporting economic development, and contributing to global security. This study highlights the urgency of adapting dynamic, inclusive interventions to combat the rising tide of antimicrobial resistance.

The global demand for seafood necessitates robust food safety practices, particularly within traditional wet markets. This study investigated the microbiomes of live Japanese mantis shrimp (JMS) and their associated environments (water and biofilm) in local wet markets to assess the risk of pathogen and antibiotic resistance gene (ARG) transfer. Metagenomic analysis showed a significant link between microbiome composition and the type of sample (shrimp, biofilm, and water). While several known human pathogens were associated with shrimp samples, water and biofilm samples exhibited higher abundances of ARGs, suggesting a high risk of pathogen and ARG transfer from the market environment. Notably, this study focused on the diversity and characterization of poorly understood Vibrio species associated with JMS. The prevalence of β-lactam resistance genes in Vibrio isolates, combined with a comparative genomic analysis of several species, highlights this concern. Our study emphasizes the need to improve hygiene practices in wet markets to reduce foodborne illness risks and address antibiotic resistance. This work represents, to our knowledge, the first comparative genomic analysis of Vibrio species in the context of JMS and wet market seafood safety.

In one of its reports, the WHO published a list of the pathogenic bacteria that pose the greatest threat to human health due to their rapidly growing resistance to currently used antibiotics. This group is called "ESKAPE" and includes, among others, Gram-positive, resistant strains of Staphylococcus aureus. This bacterium can cause a range of infections, from folliculitis and abscesses to severe cases like sepsis, and causes approximately 15% of invasive infections in hospitals worldwide. Methicillin-resistant S. aureus (MRSA), in addition to resistance to β-lactam antibiotics, is resistant to aminoglycosides, fluoroquinolones, macrolides, chloramphenicol, and tetracycline. Some strains can produce a biofilm. The growing resistance of bacteria to available antibiotics forces us to search for alternative antibacterial drugs. Plants of the genus Rubus are a source of natural compounds used in many infectious diseases. Rubus caesius (dewberry) contains, among others, anthocyanins, tannins, flavonoids, and phenolic acids known for their antioxidant and antibacterial properties [1]. However, there are no reports on the antibacterial activity of blackberry leaves (L_H2O, L_EtOH) against S. aureus. The activity of the extracts was tested in vitro on reference strains of S. aureus and clinical strains of MRSA (MIC 0.16 - 3.125 mg/ml, MBC 0.78 - 6.25 mg/ml). We studied the interactions of amikacin and cefoxitin with the tested R. caesius extracts and their effect on the inhibition of biofilms produced by clinical strains of MRSA. We show that the extracts tested have a bactericidal effect on clinical strains and inhibit biofilm formation. We suggest that our results will influence a reduction in antibiotic doses and increase their therapeutic effect, which may potentially lead to a faster elimination of microorganisms from the human body.

Reference:

Hering, A.; et al. Polyphenolic Characterization, Antioxidant, Antihyaluronidase and Antimicrobial Activity of Young Leaves and Stem Extracts from Rubus caesius L. Molecules 2022, 27, 6181. https://doi.org/10.3390/ molecules27196181

The increasing threat of antimicrobial resistance (AMR) necessitates novel and complementary approaches to monitor and mitigate its spread in animal-derived biofluids such as milk. Our research applies omics sciences, particularly proteomics and metaproteomics, to detect AMR-related proteins and antimicrobial peptides (AMPs), providing crucial insights into the microbial consortia present in raw milk. By integrating liquid atmospheric pressure matrix-assisted laser desorption/ionization (LAP-MALDI) mass spectrometry (MS) profiling, bottom-up proteomics, and metaproteomics, we characterized AMR-related proteins in milk from intensive (Pezzata Rossa, Bruna Alpina, and Frisona) and non-intensive (Podolica) farming systems. Our findings revealed the presence of β-lactamases and tetracycline resistance proteins in all samples, confirming raw milk as a potential bioindicator of AMR circulation.

In parallel, our research also explored sustainable antimicrobial strategies by evaluating the inhibitory potential of plant-derived essential oils (EOs) against Staphylococcus xylosus, an opportunistic pathogen associated with bovine mastitis. An EO blend composed of Myrtus communis, Salvia officinalis, and Cistus ladanifer was tested alongside erythromycin for its antimicrobial efficacy. MALDI-TOF MS confirmed strain identification, and disk diffusion assays demonstrated a dose-dependent inhibitory effect of the EO blend, suggesting its potential as a complementary strategy to mitigate AMR.

These findings highlight the importance of integrating proteomics-based AMR surveillance with alternative antimicrobial strategies, such as phytocomplexes, to enhance food safety and reduce reliance on conventional antibiotics. Future studies will further investigate the synergistic potential of plant-derived antimicrobials in combination with existing therapeutic options.

The study of antibiotic producers from natural sources plays an important role in the development of new drugs. One way to search for antibiotics is the isolation of microbial antibiotic producers from insects and their products [1]. Symbionts and insect-associated microorganisms represent an almost inexhaustible source of bioactive compounds, including antibiotics [2].

In this study, we examined samples of the bark beetle typographus (Ips typographus) found in the bark of fallen spruce (Picea). The bodies of insects, previously sedated with diethyl ether, were prewashed with 80% ethyl alcohol to exclude external contaminants. Then, they were homogenized using a sterile glass rod. The obtained mass was suspended in sterile water for inoculation. The inoculum was spread on 9 × 9 cm Petri dishes with brain heart infusion solid nutrient medium (with nystatin, 50 μg/mL), potato dextrose (with tobramycin, 25 μg/mL), nutrient agar (with nystatin, 50 μg/mL), and nutrient agar (with nystatin, 50 μg/mL, and nalidixic acid, 30 μg/mL). A total of 113 microbial isolates were obtained. Antimicrobial activity was screened using the agar diffusion method against a wide range of test microorganisms: a fungus (A. niger INA 00760), a yeast (C. albicans CBS 8836), Gram-positive bacteria (B. subtilis ATCC 6633, E. faecalis ATCC 29212), and Gram-negative bacteria (E. coli ATCC 25922).

As a result, three isolates of micromycetes with pronounced antimicrobial properties were selected for further study and cultivation in liquid nutrient media. The acitve substances were identified by LC-MS. Strain K1-26 produced harzianic acid. Strain K4-28 produced aspergillic acid. Strain K2-6 produced several antibiotic substances: verruculogen, fumagillin, helvolic acid, and helvolinic acid.

This work was supported by the Russian Science Foundation, project no. 25-14-00281.

1 A. A. Baranova et al., Microorganisms, 2020, 8, 1948.

2 A. A. Baranova et al., Biology, 2022, 11, 1676.

The rapid development of antibiotic resistance has led to a constant search for and development of new antibiotic drugs. One way to search for antibiotics is to study microorganisms associated with insects [1]. For example actinomycetes isolated as insect symbionts are producers of many antibiotics and antifungal drugs [2].

In this study, samples of the remains of the inner part of spruce bark that was fed on by the bark beetle typographus (Ips typographus) were studied. Preliminary bark samples were washed with sterile water and suspended for inoculation. The inoculum was spread on 9 × 9 cm Petri dishes with solid nutrient medium brain heart infusion (with nystatin 50 μg/mL), potato dextrose (with tobramycin 25 μg/mL), nutrient agar (with nystatin 50 μg/mL), nutrient agar (with nystatin 50 μg/mL and nalidixic acid 30 μg/mL). 46 microbial isolates were isolated. Further, initial screening of antibiotic activity was done using agar diffusion method against a wide range of test microorganisms.

Based on the screening results, 10 isolates of microorganisms with pronounced antibiotic properties were selected for further study. Cultivation in liquid media led to identification of active metabolites by LC-MS for two strains. The production of the known antibiotics trichorozin and gliotoxin was observed for strain SK1-7. Trichorozin is a linear peptide belonging to the peptaibol class. The spectrum of activity of peptaibols is quite broad. Gliotoxin is a sulfur-containing mycotoxin that belongs to the class of natural 2,5-diketopiperazines with a broad spectrum of activity. The production of terreic acid, which is a covalent inhibitor of the bacterial cell wall biosynthetic enzyme UDP-N-acetylglucosamine 1-carboxyvinyltransferase, was produced by the strain SK3-18.

This work was supported by the Russian Science Foundation, project no. 25-14-00281.

1. M.I. Hutchings et al., Microbiota and Host 2023, 1, e230008.
2. Y. Long et al. BMC Microbiol 2022, 22, 80.