FIG. 1.

Analysis of restriction enzyme-digested genomic DNA by PFGE and Southern hybridization. The enzymes NotI (A) and SfiI (B) were used to cleave the DNAs extracted from the strains of A. defectiva isolated during the first, second, and third episodes of a case of IE (lanes 1 to 3, respectively). Southern blot analysis was carried out with digoxigenin-labelled DNA fragments specific for the genes ermB (lanes 3′) and tet(M) (lanes 3"). Bacteriophage λ concatemers were used as molecular-size markers (lanes M). The electrophoretic and hybridization procedures and the DNA probes used were as previously described (12).