Methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening
infections. Zinc oxide is well known
as an effective antibacterial drug against many bacterial strains.
We investigated the performance of zinc oxide nanorods synthesized
by Albmiun as a biotemplate as an antibacterial drug in this study;
the fabrication of zinc oxide nanorods was synthesized by sol–gel
methods. We performed physicochemical characterization of zinc oxide
nanorods by physiochemical techniques such as FTIR spectroscopy, X-ray
diffraction, and TEM and investigation of their antimicrobial toxicity
efficiency by MIC, ATPase activity assay, anti-biofilm activity, and
kill time assays, as well as the mecA, mecR1, blaR1, blaZ, and biofilm
genes (ica A, ica D, and fnb A) by using a quantitative RT-PCR assay
and the penicillin-binding protein 2a (PBP2a) level of MRSA by using
a Western blot. The data confirmed the fabrication of rod-shaped zinc
oxide nanorods with a diameter in the range of 50 nm, which emphasized
the formation of zinc oxide nanoparticles with regular shapes. The
results show that zinc oxide nanorods inhibited methicillin-resistant S. aureus effectively. The MIC value was 23 μg/mL.
The time kill of ZnO-NRs against MRSA was achieved after 2 h of incubation
at 4MIC (92 μg/mL) and after 3 h of incubation at 2MIC (46 μg/mL),
respectively. The lowest concentration of zinc oxide nanorods with
over 75% biofilm killing in all strains tested was 32 μg/mL.
Also, we examined the influence of the zinc oxide nanorods on MRSA
by analyzing mecA, mecR1, blaR1, and blaZ by using a quantitative
RT-PCR assay. The data obtained revealed that the presence of 2×
MIC (46 μg/mL) of ZnO-NRs reduced the transcriptional levels
of blaZ, blaR1, mecA, and mecR1 by 3.4-fold, 3.6-fold, 4-fold, and
3.8-fold, respectively. Furthermore, the gene expression of biofilm
encoding genes (ica A, ica B, ica D, and fnb A) was tested using quantitative
real-time reverse transcriptase-polymerase chain reaction (rt-PCR).
The results showed that the presence of 2× MIC (46 μg/mL)
of ZnO-NRs reduced the transcriptional levels of ica A, ica B, ica
D, and fnb A. Also, the PBP2a level was markedly reduced after treatment
with ZnO-NRs.