Prevention of bacterial resistance in urinary tract infections.

Recurrences of urinary tract infection (UTI) are frequent in many segments of the population. Most women with recurrent UTI have normal genitourinary tracts, and infection is thought to emanate from the fecal bacterial reservoir, with subsequent vaginal and periurethral colonization. The fluoroquinolones, e.g., norfloxacin, work by inhibiting the A-subunit of DNA gyrase, an essential bacterial enzyme. Plasmid-mediated resistance to the fluoroquinolones has not been reported to occur, but bacterial persistence, which is often an unstable form of resistance, may occur. Norfloxacin is able to decontaminate the anal area selectively and, while being administered, remove potential pathogens from the periurethral area for periods of up to 1 year. Additionally, preliminary data suggest that norfloxacin may prevent catheter-associated gram-negative bacilluria for an average of 17 days. Data concerning 1,130 infected patients treated with norfloxacin showed the development of resistance to be infrequent (1.7%).