Prevalence of antimicrobial resistance among urinary tract pathogens isolated from female outpatients across the US in 1999

In the United States, trimethoprim-sulphamethoxazole (TMP-SMX) is the recom mended first-line treatment for uncomplicated urinary tract infections (UTI s) in females, in regions with resistance rates of < 10-20%. Unfortunately, current data on regional resistance is often not readily available to phys icians and regional variability in resistance remains largely unknown. This report presents antimicrobial susceptibility data for TMP-SMX and three ot her commonly tested antimicrobials organized by state and region to demonst rate current regional variability in resistance in the US. In the last quar ter of 1999, 5739 fresh clinical isolates of Escherichia coli, Klebsiella p neumoniae, Proteus mirabilis and Staphylococcus saprophyticus were collecte d from 202 laboratories throughout the US. Susceptibility testing was perfo rmed against TMP-SMX, cephalothin, nitrofurantoin and ciprofloxacin using b roth microdilution. Data were analyzed by patient age and specimen source, and by state and region. In the US as a whole, resistance to TMP-SMX was 16 .8% for E. coli, 7.8% for K. pneumoniae, 12.1% for P. mirabilis and 3.0% fo r S. saprophyticus, but these rates showed considerable regional variation. By state, E. coli resistance ranged from 7.4% in Pennsylvania to 33.3% in Iowa (among states with greater than or equal to 50 isolates tested). Regio nally, resistance for all uropathogens taken together ranged from 8.5% in E ast South-Central to 22.8% in West South-Central. Ciprofloxacin demonstrate d the broadest activity of the antimicrobials tested and was more active th an TMP-SMX against all pathogens. Resistance to TMP-SMX among E. coli now a pproaches or exceeds 20% in some areas. As resistance among uropathogens re aches clinically significant levels in many areas, continued regional surve illance is essential to ensure the provision of effective empiric therapy f or urinary tract infections. (C) 2001 Elsevier Science B.V. and Internation al Society of Chemotherapy. All rights reserved.