Fig. 1

Dendrogram of 44 XbaI-digested S. sonnei isolates based on the cluster analysis of PFGE patterns. The dendrogram was constructed using the UPGMA clustering method. The corresponding antibiotic resistance profile, PFGE pattern and background information for each strain is listed on the right side of the dendrogram. R = resistance and no bacteriostatic ring; r = resistance and positive bacteriostatic ring; N = sensitive and intermediary bacteriostatic ring