Capreomycin is a peptide antibiotic, commonly grouped with the aminoglycosides, which is given in combination with other antibiotics for MDR-tuberculosis. Adverse effects include nephrotoxicity and 8th cranial auditory vestibular nerve nerve toxicity. The drug should not be given with streptomycin or other drugs that may damage the auditory vestibular nerve. Patients on this drug will often require audiology tests. Capreomycin, an important drug for the treatment of multidrug-resistant tuberculosis, is a macrocyclic peptide antibiotic produced by Saccharothrix mutabolis subspecies capreolus. The basis of resistance to this drug was investigated by isolating and characterizing capreomycin-resistant strains of Mycobacterium smegmatis and Mycobacterium tuberculosis. Colonies resistant to capreomycin were recovered from a library of transposon-mutagenized M. smegmatis.