Aug 2026· International Microbiology· 0 citations· 44 references
Medicine
TL;DR
It is suggested that biogenically synthesized MgO NPs hold considerable promise as antibacterial and antibiofilm agents against MDR Gram-negative pathogens.
Abstract
Antibiotic resistance among Gram-negative bacteria, particularly those capable of forming biofilms, has become a serious clinical challenge with limited treatment options. In this study, magnesium oxide nanoparticles (MgO NPs) were synthesized using a green, cost-effective approach based on aqueous leaf extract of Cymbopogon citratus (lemongrass) and evaluated for their antibacterial and antibiofilm potential against multidrug resistant (MDR) clinical isolates of Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Minimum inhibitory concentration (MIC) values determined by broth microdilution ranged from 250 to 500 µg/ml, and minimum bactericidal concentration (MBC) values ranged from 1000 to 2000 µg/ml. Antibacterial activity assessed by the well diffusion method was dose-dependent, with inhibition zones ranging from 18 to 28 mm. The effect of MgO NPs on biofilm formation and eradication of pre-formed biofilms was evaluated using microtiter plate assay with crystal violet staining. Percentage inhibition of biofilm formation ranged from 27 to 97.1%, while eradication of established biofilms ranged from 51.9 to 96.4%. Exposure to sub-inhibitory concentrations of MgO NPs led to a 2 to 3-fold increase in reactive oxygen species (ROS) production in treated cells compared to controls. MgO NPs also significantly reduced the protein, carbohydrate, and DNA content of the biofilm matrix. Swimming, swarming, and twitching motility were markedly reduced in treated isolates. Congo red agar assay confirmed that slime production was inhibited following NP treatment. These findings suggest that biogenically synthesized MgO NPs hold considerable promise as antibacterial and antibiofilm agents against MDR Gram-negative pathogens.
Results show that green-synthesized ZnO nanoparticles have strong antibacterial and antibiofilm potential and can boost the effectiveness of traditional antibiotics, indicating their potential as supplemental agents in MDR bacterial infection management strategies.
Jazab Naeem, Muhammad Mubeen Ahmad, Syed Kashif Raza et al.· Bulletin of University of Ag...· 0 citations
ZnO NPs showed both antibacterial and antibiofilm efficacy against drug-resistant strains of E. coli, K. pneumoniae, and S. aureus and completely eradicated E. coli biofilm in combination with gentamicin.
Akshit Malhotra, Kwthar Debbarma, Sangita Jana et al.· Pharmaceutics· 0 citations
MUR exhibits high efficacy against both planktonic and biofilm-forming MDR P. aeruginosa, and its synergy with colistin and tobramycin highlights its potential as a strategic combination partner.
Umut Yılmaz, Özlem Erkoç Güleryüz, Mehmet Ünlü et al.· Biofouling (Print)· 0 citations
BACKGROUND
Methicillin-resistant Staphylococcus aureus (MRSA) poses a growing threat in Iranian healthcare settings, and biofilm formation exacerbates treatment challenges. This study assessed the antibacterial and anti-biofilm potential of zinc oxide nanoparticles ZnONPs against 58 clinical MRSA isolates collected from hospitals in Iran.
METHODS
Isolates were identified via microbial and biochemical tests and confirmed by PCR targeting nuc (279 bp) and mecA (310 bp) genes. Antimicrobial susceptibility was evaluated using CLSI disk diffusion guidelines. The ZnONPs were synthesized by chemical precipitation. Minimum inhibitory concentrations (MICs) of ZnONPs were determined by broth microdilution, and biofilm formation/inhibition was quantified using crystal violet staining.
RESULTS
Of 131 S. aureus isolates, 58 (44.3%) were MRSA, exhibiting high resistance to Penicillin (100%), Erythromycin (91.4%), and Ciprofloxacin (74.1%), but full susceptibility to Trimethoprim-Sulfamethoxazole. ZnONPs displayed potent activity, with MICs ranging from 8 to 1024 µg/mL (MIC₅₀ = 64 µg/mL; MIC₉₀ = 512 µg/mL); 27.6% of isolates were inhibited at ≤ 16 µg/mL. Among MRSA, 15.5% were strong biofilm producers, and sub-MIC (½ MIC) concentrations of ZnONPs reduced biofilm by 82.3 ± 7.6% (P < 0.001). Dynamic light scattering confirmed nanoparticle stability (size: 29.4 ± 4.2 nm; PDI: 0.19).
CONCLUSIONS
These findings highlight ZnONPs as a promising, low-cost alternative for managing MRSA infections, particularly in biofilm-associated cases, warranting further clinical exploration in resource-limited settings.
Findings indicate that N. sativa seed extracts possess antibiofilm potential against P. aeruginosa at subinhibitory concentrations, however, as this was a purely phenotypic study, the mechanisms underlying the observed inhibition remain speculative and require direct experimental investigation.
Kehinde Sowunmi, Micheal Omeyiza Ibrahim, O. Ogundele et al.· Nepal Journal of Biotechnolo...· 0 citations
Bacterial resistance to antimicrobial drugs represents a critical threat to global health, compromising the efficacy of standard therapies. In this study, we evaluated the antimicrobial properties of silver vanadate microrods (SVMs) against clinical isolates of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. SVMs were active against all tested isolates, with MIC values of 128 µg/mL for S. aureus and 256 µg/mL for Gram-negative species. Notably, checkerboard assays revealed synergistic interactions with azithromycin, clindamycin, and sulfamethoxazole (FICi 0.093-0.125), indicating that SVM might potentiate the activity of antimicrobial drugs. The MBC/MIC ratio classified SVM as bactericidal against Gram-negative isolates and bacteriostatic against S. aureus. Scanning electron microscopy suggested a membrane disruption mechanism by a direct nanoparticle-bacteria interaction. SVM also exhibited anti-inflammatory activity comparable to tenoxicam in vitro. SVM presented cytotoxicity to BGM cells at 3.13 µg/mL (CC50). Our findings suggest that SVM is a promising candidate for combination therapy, warranting further investigation with surface-functionalized formulations to improve its selectivity.
Juliane Zacour Marinho, Luiz Felipe Carreiro Machado, I. P. Ceravolo et al.· GAZI UNIVERSITY JOURNAL OF S...· 0 citations
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