Changes in urinary pathogens and their antibiotic sensitivities, 1971-1992.

Unselected urinary pathogens from general practice and hospital have been tested for sensitivity to a range of antimicrobial agents for the last 22 years. There have been substantial changes. In general practice there has been a considerable increase in the proportion of staphylococcal infections from 5.1% to a peak of 14.8% in 1982 and a more recent decline to 4.0%. There has also been a decrease in the proportion caused by proteus mirabilis, from 9.2% to 4.3%. Similar, but smaller, changes have been observed in the proportions of hospital urinary tract infections caused by these organisms, while the proportion of hospital infections due to Klebsiella spp. and Enterobacter spp. has fallen from 16.8% to 7.3%. These and other changes have been reflected in the changing patterns of sensitivity to antibiotics. In particular, sensitivity of urinary pathogens to ampicillin/amoxycillin has continued to fall both in general practice and in hospital. Nalidixic acid resistance is becoming more important as the proportion of Gram-positive urinary pathogens (especially enterococci) increases. More organisms were sensitive to ciprofloxacin than the other drugs tested, with little evidence of increasing resistance.