[Urinary tract infections and antibiotic resistance]

Urinary tract infections (UTI) are diseases which differ considerably regarding pathogenesis, natural history and management. Complicated UTI as well as uncomplicated acute pyelonephritis in women are managed with pretherapy urine and, possibly, blood culture. This is not the case, however, with the most frequent UTI, acute uncomplicated cystitis in women. Empirical management strategies, without pretherapy culture, are well established and widely used. The treatment of choice is trimethoprim-sulfamethoxazole (TMP-SMZ) and fluoroquinolones. E. coli cause the vast majority of these infections, and resistance to TMP-SMZ has been observed to increase considerably during the last decade. Data from Europe and Switzerland regarding resistance of etiologic agents causing acute uncomplicated cystitis are very limited. Indeed, these empirical management strategies have resulted in poor microbiological information, since only selected groups of women with UTI undergo urine culture. Data derived from laboratory isolates usually lack the necessary clinical and epidemiological correlations. Preliminary data allow some estimates of the clinical and microbiological success rates when treating TMP-SMZ resistant uropathogens with TMP-SMZ. TMP-SMZ should probably no longer be used if the prevalence of TMP-SMZ resistance among uropathogens causing acute uncomplicated cystitis is 20% or higher. In these cases, a fluoroquinolone during three days, amoxicillin-clavulanate during three to five days or nitrofurantoin during seven days should be given empirically. Non-antibiotic means of preventing UTI, such as increasing colonization resistance with lactobacilli, or the use of vaccines which provide inhibition of adherence of uropathogens to uroepithelial cells, show very promising experimental results. In order to survey and correct the value of our empirical strategies, more appropriate data on antimicrobial resistance and risk factors in the community are needed. This data can only be produced by a strong collaboration effort with networks of general practitioners.