Kanamycin A is a broad spectrum antibiotic. Kanamycin A was first isolated in 1957 by Hamao Umezawa from the bacterium Streptomyces kanamyceticus. In vitro: In previous study, kanamycin A was found to block a single cycle of translocation on the poly[U]-ribosome, carrying N-acetyl-diPhe-tRNA on the acceptor site and deacylated tRNA at the donor site. The GTPase reaction, catalyzed by EF-G and ribosomes, was not significantly affected by kanamycin A. The results with kanamycin A differed from those obtained with fusidic acid, suggesting that the mechanism of translocation inhibition might be differen . In vivo: Twelve male Lister hooded rats were conditioned to discriminate an 8 kHz tone and were subsequently injected subcutaneously with kanamycin A for 28 days. Results showed that only one rat was unaffected by the kanamycin A. The onset of hearing impairment generally occurred during the fourth week of kanamycin dosage although the earliest onset was towards the end of the second week. In most animals the hearing impairment progressed after kanamycin A was stopped and in one rat there was a latency between the end of drug dosage and onset of hearing impairment . Clinical trial: Kanamycin A is an antibiotic used to treat severe bacterial infections and tuberculosis. It is not a first line treatment. Kanamycin A is recommended for short-term use only .