[The role of 4-quinolones and antibiotics in the elimination of virulence plasmids of Enterobacteriaceae].

Twenty-six antibiotics belonging to thirteen different chemical families had been tested on seven Enterobacteriaceae harbouring a virulence plasmid (Shigella sonnei, S. flexneri, S. dysenteriae, Escherichia coli (two plasmids). Yersinia and Salmonella dublin). Novobiocin and rifampicin were found to be most efficient eliminating three plasmids of which two come from Shigella. Clindamycin, cotrimoxazole, nifurzide, ciprofloxacin, and tilbroquinol were also efficient, but at lower rate. Four virulence plasmids (from the three Shigella sp and Y. pestis) were eliminated by one or several antibiotics. The frequency of elimination was low (at best 10% bacteria per generation). The plasmid pWR105 from S. sonnei was the less stable.