Fluoroquinolones and resistance in the treatment of uncomplicated urinary tract infection.

Acute uncomplicated cystitis is one of the most common problems for which young women seek medical attention. Most of these infections are caused by Escherichia coli which are susceptible to many oral antimicrobials, although resistance is increasing to some of the commonly used agents, especially trimethoprim/sulphamethoxazole (TMP/SMX). In women with risk factors for infection with resistant bacteria, or in the setting of a high prevalence of TMP/SMX resistance, a fluoroquinolone or nitrofurantoin should be considered for empirical treatment. Use of nitrofurantoin does not share cross-resistance with more commonly prescribed antimicrobials and its more widespread use is justified from a public health perspective as a fluoroquinolone-sparing agent. beta-lactams and fosfomycin should be considered second-line agents for empirical treatment of cystitis. For acute uncomplicated pyelonephritis, fluoroquinolones are superior to TMP/SMX for empirical therapy due to the relatively high prevalence of TMP/SMX resistance among uropathogens causing pyelonephritis. TMP/SMX, effective for patients with mild to moderate disease, is an appropriate drug if the uropathogen is known to be susceptible. It is reasonable to use a 7-10 day oral fluoroquinolone regimen for outpatient management of mild to moderate pyelonephritis in the setting of a susceptible causative pathogen and rapid clinical response to therapy. Most women with acute uncomplicated pyelonephritis are now managed safely and effectively as outpatients.