Figure 1.

Flow chart of the study population. Group 1: first sample sensitive and second resistant to macrolides. Group 2: first and second samples both sensitive or both resistant. Group 3: 12 couples/groups of 26 sexual contacts (11 cases of two couples and one group of four patients); groups 1 and 3 shared nine samples of four patients (one patient provided 3 samples). Group 4: not related and randomly distributed samples. *65 unrelated patients in the study (34 from groups 1–3 and 31 from group 4).