[Epidemiology and etiology of urinary tract infections in the community. Antimicrobial susceptibility of the main pathogens and clinical significance of resistance].

Urinary tract infections (UTI) are a frequent problem in primary care. They occur mainly in women without underlying diseases and with no functional or structural anomalies of the urinary tract; consequently most cases are considered uncomplicated UTI. Etiology is influenced by factors such as age, diabetes, spinal cord injury, urinary catheterization, and other factors. Escherichia coli causes 80-85% of acute episodes of uncomplicated cystitis. Staphylococcus saprophyticus, Proteus mirabilis, Streptococcus agalactiae and Klebsiella spp. are responsible for most of the remaining episodes. The spectrum of bacteria that causes complicated UTI is much broader. Rates of resistance have undergone considerable variations, and consequently the empirical treatment of UTI requires constant updating of the antibiotic sensitivity of the main uropathogens of the area, country or institution. To correctly interpret the global data on sensitivity, the type of UTI (uncomplicated versus complicated), sex, age and previous antibiotic therapy in each patient must be taken into account. Resistance in uncomplicated UTI has clinical significance (although less than in systemic infections such as bacteremia), which depends on whether the infection is cystitis or pyelonephritis.