menu Journals Antioxidants Volume 13 Issue 4 10.3390/antiox13040428 Download PDFsettingsOrder Article Reprints Open AccessArticle Chitosan-Loaded Lagenaria siceraria and Thymus vulgaris Potentiate Antibacterial, Antioxidant, and Immunomodulatory Activities against Extensive Drug-Resistant Pseudomonas aeruginosa and Vancomycin-Resistant Staphylococcus aureus: In Vitro and In Vivo Approaches by Selwan M. Taha 1ORCID,Norhan K. Abd El-Aziz 2,*ORCID,Adel Abdelkhalek 3,Ioan Pet 4,*ORCID,Mirela Ahmadi 4ORCID andSameh M. El-Nabtity 1 1 Department of Pharmacology, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Egypt 2 Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Egypt 3 Food Safety, Hygiene and Technology Department, Faculty of Veterinary Medicine, Badr University in Cairo (BUC), Badr City 11829, Egypt 4 Department of Biotechnology, Faculty of Bioengineering of Animals Resources, University of Life Sciences “King Mihai I” from Timisoara, 300645 Timisoara, Romania * Authors to whom correspondence should be addressed. Antioxidants 2024, 13(4), 428; https://doi.org/10.3390/antiox13040428 Submission received: 8 February 2024 / Revised: 17 March 2024 / Accepted: 22 March 2024 / Published: 30 March 2024 (This article belongs to the Special Issue Bioactive Compounds: Antioxidant, Antibacterial, Anti-inflammatory Modulation) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract Antimicrobial resistance poses considerable issues for current clinical care, so the modified use of antimicrobial agents and public health initiatives, coupled with new antimicrobial approaches, may help to minimize the impact of multidrug-resistant (MDR) bacteria in the future. This study aimed to evaluate the antimicrobial, antioxidant, and immunomodulatory activities of Lagenaria siceraria, Thymus vulgaris, and their chitosan nanocomposites against extensive drug-resistant (XDR) Pseudomonas aeruginosa and vancomycin-resistant Staphylococcus aureus (VRSA) using both in vitro and in vivo assays. The in vitro antimicrobial susceptibilities of P. aeruginosa and VRSA strains revealed 100% sensitivity to imipenem (100%). All P. aeruginosa strains were resistant to cefoxitin, cefepime, trimethoprim + sulfamethoxazole, and fosfomycin. However, S. aureus strains showed a full resistance to cefoxitin, amoxicillin, ampicillin, erythromycin, chloramphenicol, and fosfomycin (100% each). Interestingly, all S. aureus strains were vancomycin-resistant (MIC = 32–512 μg/mL), and 90% of P. aeruginosa and S. aureus strains were XDR. The antimicrobial potential of Lagenaria siceraria and Thymus vulgaris nanocomposites with chitosan nanoparticles demonstrated marked inhibitory activities against XDR P. aeruginosa and VRSA strains with inhibition zones’ diameters up to 50 mm and MIC values ranging from 0.125 to 1 μg/mL and 1 to 8 μg/mL, respectively. The results of the in vivo approach in male Sprague Dawley rats revealed that infection with P. aeruginosa and S. aureus displayed significant changes in biochemical, hematological, and histopathological findings compared to the negative control group. These values returned to the normal range after treatment by chitosan nanoparticles, either loaded with Lagenaria siceraria or Thymus vulgaris. Real-time quantitative polymerase chain reaction (RT-qPCR) findings presented significant upregulation of the relative expression of the IL10 gene and downregulation of the IFNG gene throughout the experimental period, especially after treatment with chitosan nanoparticles loaded either with Lagenaria siceraria or Thymus vulgaris in comparison to the positive control groups. In conclusion, this is the first report suggesting the use of Lagenaria siceraria and Thymus vulgaris nanocomposites with chitosan nanoparticles as a promising contender for combating XDR P. aeruginosa and VRSA infections as well as a manager for inflammatory situations and oxidative stress-related disorders.