Urinary tract infection and drug-resistant bacteria in different patient populations.

A 1-year survey of the pathogens causing urinary tract infections was conducted in three institutions: a rehabilitation hospital, a general hospital and outpatient clinics. Gram-negative rods accounted for 96% of the infections. In the general hospital and the outpatient clinics, Escherichia coli was the most prevalent pathogen, while Proteus sp. were most prevalent in the rehabilitation hospital. The frequency of drug-resistant isolates was significantly higher in the rehabilitation hospital than in the general hospital and the outpatient clinics. This was most conspicuous in the use of the beta-lactam antibiotics, aminoglycosides and sulfonamides against such organisms as E. coli, Klebsiella sp., Enterobacter sp. and Proteus sp. Urinary E. coli were more sensitive to antimicrobial drugs than were other urinary pathogens. Pseudomonas aeruginosa isolates were highly resistant to most antibiotics. About half of the isolates were resistant to gentamicin and another half to carbenicillin. In some instances the frequency of drug-resistant isolates was higher in the general hospital than in the outpatient clinics, reflecting the greater usage of antimicrobials in the general hospital.