Tan Xiaojuan, Qin Nan, Wu Chunyan, Sheng Jiyang, Yang Rui, Zheng Beiwen, Ma Zhanshan, Liu Lin, Peng Xinhua, Jia Aiqun
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
State Key Laboratory for Diagnosis and Treatment of Infectious Disease, the First Affiliated Hospital, Zhejiang University, Hangzhou 310003, China.
Sci Rep. 2015 Jul 7;5:11997. doi: 10.1038/srep11997.
Biofilm formation is regarded as one of the major determinants in the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) as pathogens of medical device-related infection. However, methicillin-susceptible S. aureus (MSSA) can also form biofilm in vitro and such biofilms are resistant to vancomycin. Hence, researching the possible mechanisms of MSSA biofilm formation is urgent and necessary. Here, we used S. aureus ATCC25923 as the model strain, and studied gene expression profiles in biofilms after the treatment of ursolic acid and resveratrol using RNA-seq technology. The results showed that only ursolic acid could inhibit biofilm formation, which differed from their applied on the multiple clinical drugs resistant MRSA biofilm. RNA-seq data was validated by examining the expression of six genes involved in biofilm formation by qRT-PCR. These data analysis indicated that the mechanism of the MSSA biofilm formation was different from that of the MRSA, due to absence of accessory gene regulator (agr) function. These findings suggest that biofilms of S. aureus with agr dysfunction may be more resistant than those with agr function. Therefore, the infection from clinical MSSA may be recalcitrant once forming biofilm. Further study is necessary to uncover the mechanisms of biofilm formation in other clinical S. aureus.
生物膜形成被认为是耐甲氧西林金黄色葡萄球菌（MRSA）作为医疗器械相关感染病原体流行的主要决定因素之一。然而，甲氧西林敏感金黄色葡萄球菌（MSSA）也能在体外形成生物膜，且这种生物膜对万古霉素耐药。因此，研究MSSA生物膜形成的可能机制迫在眉睫且十分必要。在此，我们以金黄色葡萄球菌ATCC25923作为模式菌株，利用RNA测序技术研究了熊果酸和白藜芦醇处理后生物膜中的基因表达谱。结果表明，只有熊果酸能抑制生物膜形成，这与它们应用于多重临床耐药MRSA生物膜的情况不同。通过qRT-PCR检测参与生物膜形成的六个基因的表达，对RNA测序数据进行了验证。这些数据分析表明，由于缺乏辅助基因调节子（agr）功能，MSSA生物膜形成的机制与MRSA不同。这些发现表明，agr功能失调的金黄色葡萄球菌生物膜可能比具有agr功能的生物膜更具耐药性。因此，临床MSSA一旦形成生物膜，感染可能难以控制。有必要进一步研究以揭示其他临床金黄色葡萄球菌生物膜形成的机制。
