Efficacy of selenium in controlling Acinetobacter baumannii associated wound infections

Acinetobacter baumannii is a multi-drug resistant, nosocomial pathogen causing a variety of disease conditions, especially wound infections in humans. A. baumannii's ability to form biofilms and colonize epithelial cells potentially makes it difficult to treat skin and soft-tissue infections of this pathogen. Thus, in light of the multidrug resistance and biofilm producing capacity, new strategies for controlling A. baumannii wound infections are necessary. This study investigated the efficacy of the essential mineral, selenium (Se) in inhibiting skin-colonizing and biofilm forming abilities of A. baumannii in vitro. The effect of Se on A. baumannii adhesion and invasion of human skin keratinocytes (HEK001) was studied. Additionally, the efficacy of Se in inhibiting A. baumannii biofilm formation was determined using an in vitro collagen matrix wound model, and scanning electron microscopy (SEM) was done to visualize its potential antibiofilm effect. The effect of Se on critical A. baumannii genes for biofilm synthesis was also determined using real-time qPCR (RT-qPCR). Selenium inhibited A. baumannii biofilm formation in the collagen-based wound model and reduced bacterial adhesion and invasion of HEK001 (P < 0.05). Scanning electron microscopy revealed that Se disrupted A. baumannii biofilm architecture. RT-qPCR results indicated that Se significantly down-regulated the transcription of genes associated with A. baumannii biofilm production (P < 0.05). Results suggest that Se could potentially be used to control A. baumannii wound infections but follow up investigation in an appropriate mammalian model is warranted.