Scanning electron microscopy analyses of biofilms formed by C. tropicalis alone or in combination with E. coli and/or S. marcescens. (A) C. tropicalis plus E. coli (magnification, ×1,057); (B) C. tropicalis plus S. marcescens (magnification, ×1,000); (C) C. tropicalis plus E. coli plus S. marcescens (magnification, ×1,000); (D) C. tropicalis plus E. coli (magnification, ×5,000); (E) C. tropicalis plus S. marcescens (magnification, ×5,000); (F) C. tropicalis plus E. coli plus S. marcescens (magnification, ×5,000).