Chromosomal aberrations in human lymphocytes exposed in vitro to enrofloxacin and ciprofloxacin

Chromosomal aberrations were evaluated in cultures of human peripheral lymp hocytes from eight healthy donors, exposed to the antimicrobial enrofloxaci n (EFX) or to its major metabolite ciprofloxacin (CFX). In both treatments cultures revealed an increase in the chromosomal aberration level, detected as chromatid and chromosome breaks and gaps. Control cultures analysis rev ealed 3.6 +/- 0.6 chromosomal aberrations per 100 cells while treated cultu res exhibited 8.3 +/- 0.8 and 9.6 +/- 1.2 aberrations at 5 and 50 mu g/ml o f EFX respectively. In CFX treated cultures it was found 5.6 +/- 1.3 and 7. 7 +/- 3.5 aberrations/100 cells at 5 and 25 mu g/ml antimicrobial concentra tion. These results suggested a genotoxic effect of EFX and CFX in the syst em used (P < 0.001). A reduction in the mitotic index and fuzzy metaphases were observed at 50 mu g/ml of CFX, indicating a cytotoxic effect produced by this antimicrobial. (C) 1999 Elsevier Science Ireland Ltd. All rights re served.