Trends in antimicrobial resistance among urinary tract infection isolates of Escherichia coli from female outpatients in the United States.
The Infectious Diseases Society of America advocates trimethoprim-sulfamethoxazole (SXT) as initial therapy for females with acute uncomplicated bacterial cystitis in settings where the prevalence of SXT resistance does not exceed 10 to 20%. To determine trends in the activities of SXT, ampicillin, ciprofloxacin, and nitrofurantoin among urine isolates of Escherichia coli from female outpatients, susceptibility testing data from The Surveillance Network (TSN) Database-USA (n = 286,187) from 1995 to 2001 were analyzed. Resistance rates among E. coli isolates to ampicillin (range, 36.0 to 37.4% per year), SXT (range, 14.8 to 17.0%), ciprofloxacin (range, 0.7 to 2.5%), and nitrofurantoin (range, 0.4 to 0.8%) varied only slightly over this 7-year period. Ciprofloxacin was the only agent studied that demonstrated a consistent stepwise increase in resistance from 1995 (0.7%) to 2001 (2.5%). In 2001, SXT resistance among E. coli isolates was >10% in all nine U.S. Bureau of the Census regions. At institutions testing > or =100 urinary isolates of E. coli (n = 126) in 2001, ampicillin (range, 27.3 to 98.8%) and SXT (range, 7.5 to 47.1%) resistance rates varied widely while ciprofloxacin (range, 0 to 12.9%) and nitrofurantoin (range, 0 to 2.8%) resistance rates were more consistent. In 2001, the most frequent coresistant phenotypes were resistance to ampicillin and SXT (12.0% of all isolates; 82.3% of coresistant isolates) and resistance to ampicillin, ciprofloxacin, and SXT (1.4% of all isolates; 9.9% of coresistant isolates). Coresistance less frequently included resistance to nitrofurantoin (3.5% of coresistant isolates) than resistance to ciprofloxacin (15.8%), SXT (95.7%), and ampicillin (98.1%). In conclusion, among urinary isolates of E. coli from female outpatients in the United States, national resistance rates to SXT were relatively consistent (14.8 to 17.0%) from 1995 to 2001 but demonstrated considerable regional and institutional variation in 2001. Therapies other than SXT may need to be considered in some locations.
Focus Technologies, Inc., 13665 Dulles Technology Drive, Suite 200, Herndon, VA 20171-4603, USA. jkarlowsky@focusanswers.com
James A
JA
Karlowsky
Laurie J
LJ
Kelly
Clyde
C
Thornsberry
Mark E
ME
Jones
Daniel F
DF
Sahm
D000667:Ampicillin / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology; D000892:Anti-Infective Agents, Urinary / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D016208:Databases, Factual; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D005843:Geography; D006801:Humans; D008826:Microbial Sensitivity Tests; D009582:Nitrofurantoin / Q000494:pharmacology; D010045:Outpatients; D010406:Penicillins / Q000494:pharmacology; D010641:Phenotype; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014481:United States / Q000453:epidemiology; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000382:microbiology*
D000890:Anti-Infective Agents; D000892:Anti-Infective Agents, Urinary; D010406:Penicillins; D002939:Ciprofloxacin; D000667:Ampicillin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D009582:Nitrofurantoin