Cytogenetic effect of colistin on human lymphocytes in vitro: chromosome aberrations, sister chromatid exchanges, mitotic index, cell cycle kinetics, and acrocentric associations.

Colistin, a peptide antibiotic, was tested at three different concentrations--71, 142, and 214 units/ml. One hundred forty-two units per milliliter corresponds to the plasma level after receiving therapeutic dose. There was a dose-dependent increase in the frequency of chromosome aberrations irrespective of the duration of treatment (T0, T24, T48). This antibiotic decreased the mitotic index and delayed the cell turn over rate indicating inhibition of DNA synthesis by it. Inhibition of DNA synthesis probably results in increase in the frequency of chromosome aberrations. Frequency of satellite associations of acrocentric chromosomes was increased with increasing concentration of the drug, but the differences at three concentrations were not significant compared to controls. There was no increase in the frequency of SCEs at any concentration or duration of treatment compared to controls. It appears that colistin induces the type of lesions that lead to chromosome aberrations and not to SCEs.