Clinical applications of quinolones.

The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.