Bacteria That Cause UTI Most Susceptible to Ciprofloxacin - urinary tract infection

American Family Physician,  April 15, 2001  by Daniel Sahm

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(Interscience Conference on Antimicrobial Agents and Chemotherapy) According to results of a study, bacteria that commonly cause urinary tract infection (UTI) were more susceptible and least resistant to fluoroquinolone ciprofloxacin compared with cephalothin, trimethoprim-sulfamethoxazole (TMP-SMX) and nitrofurantoin.

Ciprofloxacin was the only antimicrobial for which the single drug resistance rate never exceeded 1 percent. During 1999, more than 9,500 UTI bacterial isolates (including Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis) were collected from 202 hospitals in the United States and tested for their susceptibility and resistance to these four antibiotics. Isolates of all three types of bacteria were highly susceptible to ciprofloxacin: 97 percent to E. coli, 96 percent to K. pneumoniae and 87 percent to P. mirabilis strains. Corresponding values for the other three antibiotics were not as consistent. Cephalothin had susceptibility rates of 70 percent to E. coli, and 89 percent to K. pneumoniae and P. mirabilis; TMP-SMX had susceptibility rates of 83 percent to E. coli, 90 percent to K. pneumoniae and 83 percent to P. mirabilis; nitrofurantoin had susceptibility rates of 99 percent to E. coli, 61 percent to K. pneumoniae and zero percent to P. mirabilis. Ciprofloxacin had the lowest overall rating of single drug resistance. Resistance to ciprofloxacin was found in 0.3 percent of strains of E. coli, 0.5 percent of K. pneumoniae and 0.8 percent of P. mirabilis. Comparatively, cephalothin was 6 percent resistant to E. coli, 1.4 percent to K. pneumoniae and 0.3 percent to P. mirabilis; TMP-SMX was 12 percent resistant to E. coli, 5 percent to K. pneumoniae and 1.2 percent to P. mirabilis; nitrofurantoin was 0.2 percent resistant to E. coli, 9 percent to K. pneumoniae and 100 percent to P. mirabilis.--DANIEL SAHM, PH.D., MRL Reference Laboratory, Herndon, Virginia. n

COPYRIGHT 2001 American Academy of Family Physicians
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