Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
Medical School, Faculty of Health and Medical Sciences, The University of Western Australia, Nedlands, Western Australia, Australia.
Sci Rep. 2019 Apr 19;9(1):6300. doi: 10.1038/s41598-019-42353-0.
Despite strengthened antimicrobial therapy, biofilm infections of Acinetobacter baumannii are associated with poor prognosis and limited therapeutic options. Assessing antibiotics on planktonic bacteria can result in failure against biofilm infections. Currently, antibiotics to treat biofilm infections are administered empirically, usually without considering the susceptibility of the biofilm objectively before beginning treatment. For effective therapy to resolve biofilm infections it is essential to assess the efficacy of commonly used antibiotics against biofilms. Here, we offer a robust and simple assay to assess the efficacy of antibiotics against biofilms. In the present work, we carefully optimized the incubation time, detection range, and fluorescence reading mode for resazurin-based viability staining of biofilms in 96-well-plates and determined minimal biofilm eradication concentrations (MBECs) for A. baumannii isolates from patients with chronic infection. By applying this assay, we demonstrated that antibiotic response patterns varied uniquely within the biofilm formation of various clinical samples. MBEC-50 and 75 have significant discriminatory power over minimum inhibitory concentrations for planktonic suspensions to differentiate the overall efficiency of an antibiotic to eradicate a biofilm. The present assay is an ideal platform on which to assess the efficacy of antibiotics against biofilms in vitro to pave the way for more effective therapy.
尽管加强了抗菌治疗，鲍曼不动杆菌的生物膜感染仍与预后不良和治疗选择有限相关。评估浮游菌中的抗生素可能导致对抗生物膜感染的失败。目前，治疗生物膜感染的抗生素是经验性给药的，通常在开始治疗前不考虑生物膜的敏感性。为了有效地治疗生物膜感染，评估常用抗生素对生物膜的疗效至关重要。在这里，我们提供了一种稳健而简单的测定法来评估抗生素对生物膜的疗效。在本工作中，我们仔细优化了 96 孔板中生物膜基于 Resazurin 的活力染色的孵育时间、检测范围和荧光读数模式，并确定了来自慢性感染患者的鲍曼不动杆菌分离株的最小生物膜清除浓度 (MBEC)。通过应用该测定法，我们证明了抗生素反应模式在各种临床样本的生物膜形成中独特地变化。MBEC-50 和 75 对于区分抗生素根除生物膜的整体效率的浮游菌悬液的最小抑菌浓度具有显著的区分能力。本测定法是体外评估抗生素对生物膜疗效的理想平台，为更有效的治疗铺平了道路。
