Bacteriologic diagnosis and antibiotic therapy of urinary tract infections

The laboratory diagnosis and antibiotic treatment of urinary tract infections (UTIs) are very different depending on the clinical context. It is critical to distinguish between uncomplicated infections and infections complicated by abnormalities of the urinary tract or other host factors. Microscopic examination combined with urine culture remains the test of reference, excepted for uncomplicated cystitis. It requires rigorous method and analysis taking into account of clinical data. For empirical therapy, the choice is well codified in case of community acquired UTIs since the bacterial species involved are very stable over time and space, and since their antibiotic resistances are well known (with currently a high prevalence of resistance not only to aminopenicillins but also to amoxicillin-clavulanate and trimethoprim-sulfamethoxazole); in contrast, the treatment of nosocomial UTIs is difficult because of the diversity of causative organisms and of antibiotic resistance profiles.