Urinary tract infection (UTI) is the primary cause of hospitalary infection. We have prospectively studied during a 8-month period, 94 episodes of UTI in 61 patients with a mean age of 77 years and with a high percentage of vesical sounding (70.5%). The most frequent cause of sounding was urinary incontinence (74%) and in just 15% of all cases, there was a strict urological indication. The association fever/sounding was statistically significant (p < 0.05) and, when analyzing the prognosis factors, we observed that patients who had a significantly higher risk were those with vesical sounding (p < 0.05), fever equal to or higher than 38 degrees C and/or Pseudomonas aeruginosa isolated in their uroculture (p < 0.01). Among the microorganisms isolated, P. aeruginosa ranked in first place, followed by E. Coli. The most sensitive antibiotics in these patients were the aminoglycosides (tobramycin or gentamycin), cephtacidime and aztreonan. Finally, the percentage of coincidence between the microorganisms isolated in the uroculture and in the infections of other patients sharing the same room is significantly higher (p < 0.01) in patients with vesical sounding than in patients without it, suggesting a transmission role of the health staff.