Antimicrobial susceptibility patterns of community-acquired uropathogens in Tehran, Iran

Antibiotic resistance of urinary tract pathogens has increased worldwide. Knowledge of the antibiotic resistance patterns of uropathogens in specific geographical locations is an important factor for choosing an appropriate empirical antimicrobial treatment. The aim of this study was to provide information regarding local resistance patterns of urinary pathogens to the commonly used antibiotics in Tehran, Iran.

Urine samples collected and submitted to two pathobiology laboratories in Tehran were identified by conventional methods over a period of three years (December 2006 to May 2009). Antimicrobial resistance testing was performed by the standard disk diffusion technique in accordance with the recommendations of the Clinical and Laboratory Standards Institute.

Of the total 13,333 mid-stream urine samples collected from suspected cases of urinary tract infection, 840 (6.3%) were positive for pathogenic bacteria. Escherichia coli (E. coli) was the most common isolate (68.8%) followed by Proteus spp. (12.4%), and Klebsiella spp. (9.6%). E. coli isolates were mostly susceptible to nitrofurantoin (71.3%), followed by ciprofloxacin (68.1%); however, only 38.2% of E. coli isolates were susceptible to trimethoprim-sulfamethoxazole.

Nitrofurantoin may be considered as a first-line empiric antibacterial agent for urinary tract infections in outpatients in Tehran, Iran.