DNA-damage caused by antibiotic drugs - quinolones.

In the present investigation, the genotoxic potencies (SOSIP) of 10 antibiotic quinolones (topoisomerase LT inhibitors) were tested in the sfiA::lacZ fusion containing strain Escherichia coli PQ37 using a modified procedure of the SOS chromotest. A number of quinolones exhibited extremely high DNA damaging effects in the absence of an exogenous metabolizing system. The highest SOS inducing potencies (SOSIP) exhibited sparfloxacin with 2,400 Delta IF/nmole, ciprofloxacin (SOSIP = 184 Delta IF/nmole) and norfloxacin (SOSIP=120 Delta IF/nmole), whereas pipemic acid (SOSIP=4.6 Delta IF/nmole), cinoxacin (SOSIP=0.5 Delta IF/nmole) and nalidixic acid (SOSIP=0.5 Delta IF/nmole) showed only weak genotoxicity. The possibility of mutagenic effects caused by quinolones in eukaryotic cells is discussed.