Acinetobacter baumannii Biofilm Formation in Human Serum and Disruption by Gallium

Biofilm-associated infections caused by Acinetobacter baumannii are extremely recalcitrant to antibiotic treatment. We report that A. baumannii develops a mature biofilm when grown in complement-free human serum (HS). We demonstrate that 16 mu M gallium nitrate (GaN) drastically reduces A. baumannii growth and biofilm formation in HS, whereas 64 mu M GaN causes massive disruption of preformed A. baumannii biofilm. These findings pave the way to the repurposing of GaN as an antibiofilm agent for A. baumannii.