SDS-PAGE and immunoblot analysis of bacteria recovered from chinchilla nasal lavage fluids or middle ear effusion. (A) SDS-PAGE was performed on a 12.5% polyacrylamide gel, and proteins were visualized by Rapid Coomassie blue staining. Lanes: 1, prestained molecular weight markers; 2, parent NTHI 12; 3, streptomycin-resistant strain 12 generated through spontaneous mutation. (B and C) Young chinchillas (2 to 3 months old) were challenged intranasally with freshly cultured streptomycin-resistant NTHI 12 as described in Materials and Methods. NP lavage and aspiration of middle ear fluid were performed 4 days after bacterial inoculation. Lanes: 1, prestained molecular weight markers; 2, whole-cell lysate of streptomycin-resistant NTHI 12 inoculum; 3 and 4, whole-cell lysate of bacteria recovered from nasal lavage fluids in the presence of streptomycin; 5 and 6, whole-cell lysate of bacteria recovered from middle ear fluids in the absence of streptomycin; 7 and 8, whole-cell lysate of bacteria recovered from the same middle ear fluids in the presence of streptomycin. Proteins were visualized by Rapid Coomassie blue staining (B), and immunoblotting was performed with guinea pig anti-P6 antiserum (C).