Nosocomial urinary tract infections: secular trends, treatment and economics in a university hospital.

During a 71-month interval 3,024 nosocomial urinary tract infections were identified by prospective surveillance at our hospital. The annual attack rate varied between 2.0 and 3.1 per 100 admissions. Gram-negative bacilli caused 74 per cent of all urinary infections and recurrent infections in the hospital accounted for only 1 per cent. The most frequent pathogens were Escherichia coli (24 per cent), Pseudomonas aeruginosa (8 per cent), Streptococcus faecalis (7 per cent), Klebsiella pneumoniae (6 per cent) and Proteus mirabilis (6 per cent). Candida species caused 10 per cent of the infections and may represent a hospital-acquired pathogen of increasing importance. The burn unit had a significantly higher proportion of Enterobacter infections (21 per cent) than any other service (p less than 0.05). The plastic surgery service had more Serratia infections (24 per cent), whereas obstetrics and gynecology had more Escherichia coli infections (47 per cent) relative to other hospital services. More than 99 per cent of the patients with nosocomial urinary tract infections received antimicrobial drugs; in 63 per cent the chart documented that drug therapy was prescribed specifically for treatment of the urinary infections. Hospital-acquired urinary infections added approximately 1 million dollars to hospital expenses during the study interval. Estimates were made of the economic benefits of successful control programs.