hello doc, my son age 23. wt 49kg height 5'9 inch engineering stduent . He is suffering from mdr tb last four year,he was infected in mumbai during his education he was direct infection case of mdr tb. According to his sensitivity test he is sensitive to kanamycin , ethide .pas and cla rithromycin we are giving these medicine along with pza and ethambutal after six months kanamycin was stoped. But he is not cured still his culture is positive. Please doc. suggest how he will be negative which medicine should be added to his regiment and how long he should take the kanamycin injection.