Urinary tract infections in the city of Florence: epidemiological considerations over a twenty-year period.

Our study of significant bacteriurias indicated that the worldwide shift in the etiology of infections also holds true for the Florence area. In a twenty-year period (1970-1990), we noted a decreased frequency of Gram-negative bacilli, particularly of the family Enterobacteriaceae, and a significant increase of Gram-positive cocci in urinary patients. This finding was observed both in hospital and in community-acquired cases in the male sex and only in nosocomial bacteriurias in the female sex. There was a reduced isolation of "classic" urinary pathogens such as Proteus mirabilis: its prevalence in hospital-acquired urinary tract infection (UTI) decreased from 16% in 1970 to 5% in 1990 both in males and in females. On the other hand, we noted an increase of "difficult" microorganisms such as enterococci and methicillin-resistant staphylococci, particularly in the male sex; in 1970 enterococci were occasionally isolated in males both from hospital and from community-acquired UTIs (3% and 5%, respectively), whereas in 1990, on the contrary, they were encountered much more frequently (19% in both cases).