Changes in the antibiotic sensitivities of urinary pathogens, 1971-1989.

All urinary pathogens from general practice and hospital have been tested for sensitivity to a range of antimicrobial agents for the last 19 years. There have been marked changes during that time. 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 3.4%. There has also been a decrease in the proportion caused by Proteus mirabilis, from 9.2% to 5.0%. Similar, but smaller changes have been observed in the proportions of hospital urinary tract infections (UTI) caused by these organisms, while the proportion of hospital infections due to Klebsiella spp. and Enterobacter spp. has fallen from 16.8% to 9.2%. These and other changes have been reflected in 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 no evidence of increasing resistance over a six-year period. Over the same time there has been a reduction of overall sensitivity of urinary pathogens to trimethoprim from 90.8% to 82.5% in general practice, with no significant change in isolates from hospital practice.