Abstract: Objective To determine the occurrence mechanism clinical characteristics multidrug resistant pulmonary tuberculosis (MDR PTB) who received treatment before.Methods The clinical data of 625 cases with MDR PTB received treatment before in Guiyang pulmonary Hospital from 1992 to 2002 was analyzed.Results 625 cases with MDR PTB received treatment before occupied 30.8% in patients of retreatment bacteriological positive PTB.Young and middle age females occupied majority.The Results of susceptibility test wereas follows:7 cases with drug resistance Results to H.R. (1.1%);125 cases with drug resistance Results to 3 drugs (20.0%);493 cases with drug resistance Results to H.R.S.E.(78.9%);the initinl drug resistance rate was 19.4% and acquired resistance result was 80.6%.There were more patients in rural and town than ones in the city and the cure rate of patients come from rural area was lower than that of patients from urban area.Conclusion The treatment to post MDR PTB is more difficult than to general MDR PTB.Besides economic cultural and regional diffence,medical factor is one of mainly reasons of occurrence rate increasing.The rate of primary resistance in the cases is higher than the rate of national average resistance.The difference in effective rate of treatment in different area is because of there is short of regular treatment manage by specialist.The better effect can be got by the private treatment especially unite the operation treatment.

Key words: Pulmonary tuberculosis, MDR-TB, Post-retreatment