Methicillin-resistant Staphylococcus aureus (MRSA) continues to represent a significant clinical challenge, characterized by consistently elevated rates of morbidity and mortality. Care regimen success is still difficult and necessitates assessing new antibiotics as well as supplemental services, including source control and searching for alternative approaches to combating it. Hence, we propose to synthesize silver nanoparticles (Ag-NPs) by employing a cell-free filter (CFF) of Streptomyces sp. to augment antibiotic activity and combat biofilm-forming MRSA. Seven bacterial isolates from clinical samples were identified, antibiotics were profiled with Vitek-2, and the phenotypic detecting of biofilm with Congo red medium and microplate assay was carried out. The PCR technique was used for detecting genes (icaA and icaD) coded in biofilm forming. The characterization of Ag-NPs was performed using several analytical methods, such as UV spectroscopy, dynamic light scattering (DLS), zeta potential measurement, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The antibacterial properties of Ag-NPs and oxacillin–Ag-NPs were assessed against standard strains and clinical isolates by employing the agar well diffusion technique and the microdilution assay. The biogenic synthesis Ag-NPs resulted in uniformly spherical particles, with an average size of 20 nm. These Ag-NPs demonstrated significant activity against biofilm-forming MRSA, with minimum inhibitory concentrations (MICs) ranging from 12 to 15 μg/mL. Additionally, Ag-NPs completely impede biofilm formation by MRSA at sublethal doses of 0.75 MICs. The expression levels of the icaA and icaD genes were reduced by 1.9- to 2.2- and 2.4- to 2.8-fold, respectively. A significant synergistic effect was noted when Ag-NPs were used in combination with oxacillin, leading to reduced MICs of 1.87 μg/mL for oxacillin and 4.0 μg/mL for Ag-NPs against MRSA. The FICi of 0.375 further validated the synergistic relationship between oxacillin and Ag-NPs at the concentrations of 1.87 and 4 μg/mL. Findings from the time-kill test demonstrated the highest reduction in log₁₀ (CFU)/mL of the initial MRSA inoculum after 12-hour exposure. The cytotoxicity analysis of Ag-NPs revealed no significant cytotoxic effects on the human skin cell line HFB-4 at low concentrations, with IC₅₀ values of 61.40 µg/mL for HFB-4 and 34.2 µg/mL for HepG-2. Comparable with oxacillin–Ag-NPs, Ag-NPs showed no cytotoxic effects on HFB-4 at different concentrations and exhibited an IC₅₀ value of 31.2 against HepG-2-cells. In conclusion, the biosynthesis of Ag-NPs has demonstrated effective antibacterial activity against MRSA and has completely hindered biofilm formation, suggesting a valuable alternative for clinical applications.

We aimed to investigate the potential anticonvulsant effect of green synthetized selenium nanoparticles (SeNPs) using Syzygium aromaticum extract (SAE) (SAE-SeNPs) against epileptic seizures and cortical damage induced by pentylenetetrazole (PTZ) injection in rats and its mechanism. A total of 84 rats were divided into six groups; control, PTZ-exposed group, SAE + PTZ-treated group, sodium selenite (Na₂SeO₃) + PTZ-treated group, SAE-SeNPs + PTZ-treated group, and diazepam + PTZ-treated group. SAE-SeNPs significantly increase (p < 0.05) the latency time to seizures and reduce both the seizure duration and death rate, which were enhanced by the PTZ injection. SAE-SeNPs counteracted the PTZ-induced changes in the oxidants and antioxidants. Furthermore, SAE-SeNPs significantly restored (p < 0.05) the pro-inflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor-α) to their normal levels and suppressed the activity of the glial fibrillary acidic protein showing their inhibitory effect on the epilepsy-associated inflammation. In addition, SAE-SeNPs significantly reduced (p < 0.05) PTZ-induced cortical cell apoptosis, as revealed by a reduction in the pro-apoptotic Bax and caspase-3 levels, and an elevation of the anti-apoptotic Bcl-2 level. Moreover, SAE-SeNPs significantly modulate (p < 0.05) the PTZ-induced changes in the neurotransmitter norepinephrine level and acetylcholinesterase enzymatic activity. These data concluded the anticonvulsant activity of SAE-SeNPs via their antioxidant, anti-inflammatory, and anti-apoptotic effects, along with their ability to modulate neurotransmitters.

Introduction: Bacillus cereus (B. cereus) is widely distributed in natural environments, particularly in soil and plant matter, and is frequently linked to foodborne illness outbreaks, accounting for approximately 1.4%–12% of food poisoning cases worldwide. This study aimed to assess the presence of toxigenic and emetic genes among B. cereus isolates, evaluate their antibiotic susceptibility, and investigate the antimicrobial potential of Artemisia vulgaris (A. vulgaris) extract. Methods: Polymerase chain reaction (PCR) was employed to detect toxigenic and emetic genes in B. cereus isolates. Antibiotic susceptibility was tested against a panel of agents. The antimicrobial, antibiofilm, antioxidant, cytotoxic, and gene-suppressing activities of methanolic A. vulgaris extract were evaluated using standard microbiological, biochemical, and molecular assays. GC-MS and HPLC analyses were performed to identify major bioactive compounds. Results: PCR revealed that the isolates harbored hemolysin BL (HBL) genes hblA (8.62%) and hblB (20.68%), non-hemolytic enterotoxin (NHE) genes nheA (20.68%) and nheB (22.41%), as well as bceT (29.30%) and ces (15.51%) genes associated with emetic toxin production. Antibiotic testing showed high sensitivity to ciprofloxacin (91.37%) and rifampicin (96.54%), but strong resistance to ampicillin (86.20%) and novobiocin (65.51%). A. vulgaris extract demonstrated potent antibacterial activity (inhibition zones: 19.20 ± 0.25 mm to 27.10 ± 0.13 mm; MICs: 62.5–250 μg/mL), significantly inhibited biofilm formation, and downregulated toxigenic genes by −2.5 to −5.2 fold ( ^*** P < 0.0001). The extract also displayed strong antioxidant activity (IC ₅₀ : 12.7 μg/mL, DPPH; 14.2 μg/mL, ABTS) and low cytotoxicity (IC ₅₀ : 524.7 ± 1.23 μg/mL, Vero cells; 236.5 ± 1.74 μg/mL, HFB4 cells). GC-MS identified dopamine N,N-dimethyl-dimethyl ether (40.31%) and n-hexadecanoic acid (16.57%) as major compounds, while HPLC revealed high levels of chlorogenic acid, luteolin, and quercitrin. Discussion/conclusion: These findings highlight the public health risks posed by toxigenic B. cereus in food contamination. The methanolic extract of A. vulgaris exhibits strong antibacterial, antibiofilm, antioxidant, and gene-suppressing activities, supporting its potential as a natural therapeutic strategy against B. cereus and its virulence factors.

Nanostructured lipid carriers (NLCs), liposomes, and microemulsions represent significant advancements in drug delivery systems. This study aimed to synthesize NLCs encapsulating Bacillus megaterium supernatant (BMS) and magnetic nanoparticles (MNPs) for potential application against MRSA and cancer cells. The NLCs were prepared using the emulsification-solvent evaporation technique and loaded with BMS and MNPs to form NLC-BMS-MNPs. Characterization of the NLC-BMS-MNPs was performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential. The NLC-BMS-MNPs exhibited a spherical morphology with an average size of 74.45 nm, a polydispersity index (PDI) of 0.350, and a zeta potential of − 4.44 mV. NLC-BMS-MNPs demonstrated antibacterial activity, with minimum inhibitory concentrations (MICs) ranging from 7.5 to 30 µg/mL. They also significantly downregulated the expression of biofilm-associated genes fnbA, icaA, and cna, with fold changes ranging from − 1.9 to -3, -2 to 3, -4 to5.2, respectively (P < 0.0001). Furthermore, the formulation showed antioxidant activity, with IC₅₀ values of 299 µg/mL and 521 µg/mL in DPPH and ABTS assays, respectively. Additionally, NLC-BMS-MNPs exhibited selective cytotoxicity toward cancer cells. HepG2 and MCF-7 cells displayed significantly reduced viability, with IC₅₀ values of 13.74 ± 0.02 µg/mL and 19.12 ± 0.51 µg/mL, respectively, compared to normal Vero and HFB-4 cells, which showed IC₅₀ values of 36.1 ± 0.65 µg/mL and 33.45 ± 2.29 µg/mL. In conclusion, NLC-BMS-MNPs represent a promising multifunctional nanomaterial with potential applications in both antimicrobial and anticancer therapies.