FIG. 1.

Antibody to the poly-β-1,6-N-acetylglucosamine ECM of S. epidermidis biofilm cross-reacts with Y. pestis ECM. Immunofluorescence assays of Hms⁺ (A to D) or Hms⁻ (E and F) Y. pestis or Ica⁺ (G and H) or Ica⁻ (I and J) S. epidermidis using polyclonal antibody generated against purified Ica-dependent ECM polysaccharide of S. epidermidis are shown. Y. pestis strains were cultured at 21°C (A, B, E, and F) or 37°C (C and D); the Hms-dependent ECM is expressed only at 26°C or below (40). The matching phase-contrast image is shown to the right of each immunofluorescence image. Magnification, ×600.