FIG. 1.

Characterization of biofilm formation by S. lugdunensis clinical isolates. (A) S. lugdunensis biofilm formation on silicone elastomer. Disks cut from nonreinforced silicone elastomer sheeting were sterilized and incubated for 24 h in TSB_gluc1% (left) or TSB_gluc1% containing S. lugdunensis IDRL-2640 (right). Disks were rinsed and stained with safranin to visualize biofilms. (B) Scanning electron micrograph (magnification, ×1,800) of S. lugdunensis IDRL-2640 biofilm formed on a silicone elastomer disk after 24 h. (C) Higher-magnification (×13,000) SEM of biofilm shown in panel B. (D) Biofilm formation by S. aureus SA113, S. epidermidis RP62A, and 15 clinical S. lugdunensis isolates on polystyrene when grown in TSB_gluc1% for 24 h. Biofilms were stained with safranin, resuspended in 30% glacial acetic acid, and quantified by OD₄₉₂. Bars are the averages of measurements taken from four duplicate wells. Error bars represent the standard deviations. The assay was repeated three times, and representative data from a single replicate are shown.