Fig. 2

PFGE cluster analysis of Escherichia coli isolates from pullets and layers (restriction enzyme XbaI). The TIFF images were compared using BioNumerics 6.6 software (Applied Math NV, Sint-Martens-Latem, Belgium), and normalized using the PFGE global standard Salmonella ser. Braenderup H9812. Pattern clustering was performed using the unweighted pair group method using arithmetic averages (UPGMA) and the Dice correlation coefficient was applied with a position tolerance of 1.0 %. Information provided adjacent to the dendrogram include the PFGE-type in combination with areas of isolation (S: Styria, LA: Lower Austria, Ua: Upper Austria, Sa: Salzburg, B: Burgenland, Ca: Carinthia), number of isolates (n) in each PFGE type, organs of isolation (source) and serotype [not applicable (na) are untypeable isolates]. Furthermore, E. coli isolation was classified according to the absence (1) or presence (2) of lesions in the reproductive tract