Figure 1.

Unsupervised hierarchical clustering of cystic fibrosis (CF) clinical isolates based on presence of S. aureus toxin genes. Isolate numbers and subjects are indicated at right. Toxin genes are on the bottom margin, with members of the enterotoxin gene cluster (EGC) in blue. Letters A, B, C, D, E, and G are staphylococcal enterotoxin (SE) superantigens characterized as causing emesis after oral administration. Letters H, I, K, L, M–Q, and X are SE-like superantigens. TSST is toxic shock syndrome toxin-1 superantigen. α and β are cytotoxins. Blue shading represents toxin presence. MRSA isolates are indicated with red font. Dendrograms at left and top show relatedness of the isolates and toxins, respectively. The EGC was prevalent in both MRSA and MSSA isolates.