TL;DR
The potential of ZnO NPs are demonstrated as effective, concentration-dependent anti-biofilm agents with gene-targeted antimicrobial activity, supporting their advancement for nano biomedical applications against multi drug resistance 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.
It is suggested that biogenically synthesized MgO NPs hold considerable promise as antibacterial and antibiofilm agents against MDR Gram-negative pathogens.
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.
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.