Dapsone resistance in patients attending Central Leprosy Teaching and Research Institute, Chengalpattu (South India).

The Central Leprosy Teaching and Research Institute (C.L.T. & R.I.) Chengalpattu, took up studies on dapsone resistance in M. leprae from 1974. From 1978, the study was further strengthened by a project under THELEP (TDR) for eliciting information on the efficacy of certain drug regimens. The Thelep studies were to be conducted only on the dapsone sensitive untreated cases and, therefore, directed towards the detection of primary resistance, while the non-THELEP institutional studies were concentrated on secondary dapsone resistance problem. These two studies together detected 99 cases of dapsone resistance in the patients who attended CLTRI Hospital during 1974-81; 23 of them, were of primary origin, 16, 6 and 1 showing mild (RI), moderate (RII), and high (RIII) grades respectively. Of the remaining 76 cases of secondary resistance, 7 and 69 were of RII and RIII grades respectively. The need for vertical and horizontal monitoring of the drug resistance problem has been pointed out.