Multidrug resistant (MDR) and biofilm producing Staphylococcus aureus strains are usually associated with serious infections. This study aimed to evaluate the antibacterial and antibiofilm-formation effects of zinc oxide nanoparticles (ZnO-NPs) against staphylococcus aureus (S. aureus) isolates. A total of 116 S. aureus isolates were recovered from 250 burn wound samples. The antimicrobial/antibiofilm effects of ZnO-NPs against methicillin, vancomycin and linezolid resistant S. aureus (MRSA, VRSA and LRSA) isolates were examined using phenotypic and genotypic methods. The minimum inhibitory concentration (MIC) of ZnO-NPs was determined by microdilution method. The effects of sub-MIC concentrations of ZnO-NPs on biofilm formation and drug resistance in S. aureus were determined by the microtiter plate method. The change in the expression levels of the biofilm encoding genes and resistance genes in S. aureus isolates after treatment with ZnO-NPs was assessed by real time reverse transcriptase PCR (rt-PCR). MICs of ZnO-NPs in S. aureus isolates were (128–2048 µg/ml). The sub-MIC of ZnO-NPs significantly reduced biofilm formation rate (the highest inhibition rate was 76.47% at 1024 µg/ml) and the expression levels of biofilm genes (ica A, ica D and fnb A) with P < 0.001. Moreover, Sub-MIC of ZnO-NPs significantly reduced the rates of MRSA from 81.9 (95 isolates) to 13.30% (15 isolates), VRSA from 33.60 (39 isolates) to 0% and LARSA from 29.30 (34) to 0% as well as the expression levels of resistance genes (mec A, van A and cfr) with P value < 0.001. ZnO-NPs can be used as antibiofilm and potent antimicrobial against MRSA, VRSA and LRSA isolates.

中文翻译：

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ZnO纳米粒子对金黄色葡萄球菌分离株甲氧西林、万古霉素、利奈唑胺耐药及生物膜形成的影响

耐多药 (MDR) 和产生生物膜的金黄色葡萄球菌菌株通常与严重感染有关。本研究旨在评估氧化锌纳米粒子 (ZnO-NPs) 对金黄色葡萄球菌 (S. aureus) 分离株的抗菌和抗生物膜形成作用。从 250 个烧伤样本中回收到总共 116 个金黄色葡萄球菌分离株。使用表型和基因型方法检查了 ZnO-NPs 对甲氧西林、万古霉素和利奈唑胺耐药金黄色葡萄球菌（MRSA、VRSA 和 LRSA）分离株的抗菌/抗菌作用。ZnO-NPs的最低抑菌浓度(MIC)采用微量稀释法测定。通过微量滴定板法测定亚MIC浓度的ZnO-NPs对金黄色葡萄球菌生物膜形成和耐药性的影响。通过实时逆转录酶 PCR (rt-PCR) 评估用 ZnO-NPs 处理后金黄色葡萄球菌分离株中生物膜编码基因和抗性基因表达水平的变化。金黄色葡萄球菌分离物中 ZnO-NPs 的 MIC 为 (128–2048 µg/ml)。ZnO-NPs的亚MIC显着降低了生物膜形成率（1024 µg/ml时最高抑制率为76.47%）和生物膜基因（ica A、ica D和fnb A）的表达水平，P < 0.001。此外，ZnO-NPs 的 Sub-MIC 显着降低 MRSA 的发生率，从 81.9（95 株）降低到 13.30%（15 株），VRSA 从 33.60（39 株）降低到 0%，将 LARSA 从 29.30（34）降低到 0%。以及P值<0.001的抗性基因（mec A、van A和cfr）的表达水平。ZnO-NPs 可用作抗生物膜和有效的抗 MRSA、VRSA 和 LRSA 分离物的抗菌剂。