10.6084/m9.figshare.4212924.v1 Chen H. Chen H. Cao J. Cao J. Zhou C. Zhou C. Liu H. Liu H. Zhang X. Zhang X. Zhou T. Zhou T. Supplementary Material for: Biofilm Formation Restrained by Subinhibitory Concentrations of Tigecyclin in Acinetobacter baumannii Is Associated with Downregulation of Efflux Pumps Karger Publishers 2016 Acinetobacter baumannii Tigecycline Biofilm Efflux pump 2016-11-07 15:14:08 Dataset https://karger.figshare.com/articles/dataset/Supplementary_Material_for_Biofilm_Formation_Restrained_by_Subinhibitory_Concentrations_of_Tigecyclin_in_Acinetobacter_baumannii_Is_Associated_with_Downregulation_of_Efflux_Pumps/4212924 <i>Background:</i> Tigecycline, one of the few therapeutic options against multidrug-resistant <i>Acinetobacter baumannii,</i> reaches subinhibitory serum concentrations only with cautious clinical dosing and pharmacokinetics. Subinhibitory concentrations of tigecycline might induce an <i>A. baumannii</i> biofilm. <i>Methods:</i> Biofilm formation was assessed via the crystal violet staining method. We further analyzed the main biofilm components with NaIO4, proteinase K, and DNase. Real-time RT-PCR was applied for quantitative detection of biofilm potential-associated genes. <i>Results:</i> In this study, <i>A. baumannii </i>proved to be a strong biofilm producer, and we found that proteins and extracellular DNA are crucial components of the <i>A. baumannii </i>biofilm. Quantitative real-time RT-PCR revealed positive correlations between biofilm formation restrained by subinhibitory concentrations of tigecycline and the expression of biofilm potential-associated genes, especially the <i>AdeFGH</i> efflux pump gene. <i>Conclusion:</i> Our results suggest that downregulation of efflux pumps, especially the <i>AdeFGH</i> efflux pump, is probably responsible for the decline in biofilm formation in <i>A. baumannii</i> treated with subinhibitory concentrations of tigecyclin.