Katalin Burián

Background/Objectives: Chlamydia trachomatis (C. trachomatis) infections represent a major global public health concern, with over 100 million new cases annually. Although commonly used antibiotics like azithromycin and doxycycline are generally effective, increasing antibiotic resistance and therapeutic failures highlight the need for alternative treatments and innovative delivery systems. Methods: The efficacy of alternative antimicrobial agents, including ciprofloxacin and the combination of sulfamethoxazole and trimethoprim, was evaluated in both free and nano-formulated states. Drug encapsulation was achieved using liposomes as well as niosomal and aspasomal delivery systems. In vitro experiments were conducted on HeLa cells infected with C. trachomatis serovar D. Host cell viability and cytotoxicity were assessed using the MTT assay, while bacterial genomic load was quantified by qPCR. Results: Encapsulation significantly enhanced antimicrobial activity, with certain antibiotic-loaded lipid nanoparticles demonstrating 2–4 times greater effectiveness compared to their free counterparts. The prepared formulations exhibited no cytotoxic effects and did not interfere with PCR-based detection, confirming that observed outcomes reflect true antimicrobial activity. Conclusions: Nanocarrier-based drug delivery, particularly using lipid nanoparticles, represents a promising strategy for improving the therapeutic management of C. trachomatis infections. These findings highlight the potential of delivery platforms to enhance antibiotic performance and support the development of more effective and innovative antimicrobial therapies.

Background/Objectives: The stability and biological safety of newly developed formulations must be established to support their therapeutic efficacy and clinical translation in pulmonary drug delivery. Therefore, this follow-up study comprehensively evaluated the short- and long-term stability and the in vitro cytotoxicity of optimized, co-spray-dried theophylline (THN) dry powders for inhalation against A549 lung epithelial cells. Methods: Two established formulations were selected: THN-RAF (raffinose–leucine–glycine based) and THN-TRE (trehalose–leucine based). Stability was assessed under accelerated conditions (40 °C/75% RH, 3 months) and long-term desiccator storage (25 °C, 1 year) using laser diffraction, SEM, XRPD, FTIR, DSC, TGA, and Andersen Cascade Impaction. As THN-TRE had been previously confirmed to be cytocompatible, only THN-RAF and its components were evaluated against A549 human alveolar epithelial cells using the MTT assay. Results: Under accelerated conditions, both formulations exhibited pronounced recrystallization (Xc up to 89.9%), agglomeration (D [0.9] up to 217.08 µm for THN-TRE), and deterioration in aerodynamic performance (FPF as low as 11.55%, MMAD up to 6.68 µm). By contrast, long-term desiccator storage induced substantial recrystallization (Xc up to 80.7%) while preserving thermal, chemical, and aerodynamic performance (FPF ≈ 40%; MMAD 4.99–5.21 µm). THN-RAF was more resistant to stress-induced agglomeration than THN-TRE. Cytotoxicity assessment confirmed cytocompatibility of THN-RAF, with cell viability exceeding 70.99% at all tested concentrations (up to 500 µg/mL). Conclusions: These findings reveal a marked discrepancy between the outcomes of ICH accelerated testing and long-term desiccator storage. They underscore the importance of considering moisture-protective packaging configurations when designing stability protocols for amorphous inhalable formulations.

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major therapeutic challenge due to its extensive antibiotic resistance. This study examined how bacteriophage exposure affects the genome, proteome and antibiotic susceptibility of a clinical MRSA isolate. Methods: The MRSA isolate was exposed to the PYOFAG bacteriophage cocktail, and small colony variants (SCVs) of the surviving bacteria were compared with the untreated parental strain by phenotypic testing, whole-genome sequencing, comparative proteomics, and transmission electron microscopy. Results: Phage exposure induced marked remodeling in MRSA, including altered growth, colony morphology, and increased susceptibility to various antibiotics, especially β-lactams and aminoglycosides. Genomic analysis identified multiple mutations and the loss of two genomic regions, including changes in tarS, a gene linked to wall teichoic acid glycosylation, phage adsorption, and β-lactam resistance. Proteomic analysis revealed broad changes in metabolic, stress-response, and cell-envelope-associated pathways. Transmission electron microscopy showed a significant reduction in cell wall thickness after phage treatment. Conclusions: Bacteriophage exposure drives phenotypic and molecular adaptation in MRSA and may create evolutionary trade-offs that weaken resistance mechanisms. These findings support the potential of bacteriophages as both direct antibacterial agents and modulators of antibiotic susceptibility.

Periodontitis is a chronic inflammatory disease marked by the progressive destruction of periodontal tissues, where conventional therapies often fail to maintain adequate drug levels at the target site. This study reports the development and characterization of a thermosensitive gel containing nanostructured lipid carriers (NLC) for controlled local periodontal delivery. Apigenin (AP)-loaded NLC were prepared using AP as active agent and clove essential oil (CEO) as liquid lipid subsequently incorporated into Poloxamer 407 (5–15% w/w) hydrogels. The formulations were evaluated in relation to particle size, morphology, thermal and rheological behavior, mucoadhesion, in vitro release, antibacterial activity, and stability. Optimized nanoscale NLC showed a high entrapment efficiency, and uniform morphology. Raman analysis confirmed successful AP incorporation and homogeneous distribution in the gel without incompatibility. NLC-loaded gels exhibited sol–gel transition at physiological temperature with improved viscoelasticity and enhanced mucoadhesion. The drug release was sustained for 48 h and followed the Korsmeyer–Peppas model, indicating diffusion-based and anomalous transport. The antibacterial assessment demonstrated the pronounced inhibitory activity of the NLC formulations against key periodontal pathogens, with the formulation-dependent modulation of antimicrobial efficacy observed following the gel incorporation. Stability studies showed preserved nanoparticle structure and uniform dispersion. Overall, the thermoresponsive NLC-hydrogel system offers a promising strategy for prolonged, localized periodontal therapy.

Multidrug-resistant Pseudomonas aeruginosa is a major cause of healthcare-associated infections, particularly in high-burden clinical settings where rapid tools to capture clinically relevant resistance and virulence phenotypes are needed. In this study, we applied an integrated whole-genome sequencing (WGS) and Fourier-transform infrared (FTIR) spectroscopy approach to evaluate genotype–phenotype relationships in multidrug-resistant P. aeruginosa isolates collected during the COVID-19 pandemic. High-quality WGS data were used to characterize antimicrobial resistance determinants, mobile genetic elements, and virulence gene repertoires, while FTIR spectroscopy provided culture-based phenotypic fingerprints reflecting cell envelope composition. Genomic analyses revealed a conserved efflux-centered intrinsic resistance backbone, variably supplemented by acquired β-lactamases and aminoglycoside-modifying enzymes, alongside a largely conserved core virulome with heterogeneity driven primarily by type III secretion system effector profiles. Comparison of FTIR- and WGS-derived distance matrices revealed a weak but statistically significant global association, indicating a non-linear relationship between genomic relatedness and phenotypic similarity. Cluster-level concordance was strongly scale-dependent, with high agreement emerging only at finer clustering resolutions, consistent with FTIR capturing phenotypic variation linked to regulatory, metabolic, and cell envelope adaptations rather than deep phylogenetic structure. Together, these findings show that multidrug resistance and virulence in P. aeruginosa are shaped by a modular genomic architecture that manifests as distinct, measurable phenotypic states. The observed scale-dependent concordance supports FTIR spectroscopy as a rapid, cost-effective phenotypic screening tool for outbreak-oriented surveillance, complementing WGS in integrated antimicrobial resistance monitoring workflows.

Therapeutic strategies that fine-tune epithelial inflammatory responses are highly sought after in respiratory and mucosal disorders, but few molecules selectively target these pathways. Vernoniastrum migeodii (S. Moore) Isawumi (Asteraceae) represents a chemically promising but understudied source of bioactive small molecules. This study aimed to define the metabolite profile of V. migeodii and evaluate the modulation of inflammatory epithelial signaling of the constituents. From the methanolic extract of V. migeodii, five germacranolide sesquiterpenes, vernolide (1), 3′-hydroxylvernolide (2), pectorolide (3), 4′-hydroxypectorolide-14-O-acetate (4) and 4′-hydroxypectorolide (5), together with (6S,9R)-vomifoliol (6), eucarvone (7), luteolin (8), and luteolin-7-O-glucoside (9) were isolated by multiple chromatographic separations. The structures were determined by comprehensive 1D and 2D NMR spectroscopy. Isolated compounds 1 to 9 together with previously reported steroids (10–17) and tripeptide (18) were evaluated in LPS-activated A549 cells by quantitative PCR for interleukin-6 (IL6), interleukin-1β (IL1β), and prostaglandin-endoperoxide synthase 2 (PTGS2) and by enzyme-linked immunosorbent assay (ELISA) for IL-6 and IL-8. Compounds 2, 7, steroids 10–17 and aurantiamide acetate (18) reduced IL6 mRNA relative to the LPS control, while (6S,9R)-vomifoliol (6) increased IL-6 and elevated IL-8. In the assay IL1β and PTGS2 transcripts were not significantly altered. These findings highlight the potential of V. migeodii metabolites as modulators of epithelial inflammatory pathways. Combining chemical and biological evidence provides a clear basis for structure–activity- and pathway-focused studies.