Uropathogenic properties of Escherichia coli in recurrent urinary-tract infection.

Properties of Escherichia coli considered to be important in the pathogenesis of urinary-tract infection were investigated. The following properties were more common in E. coli strains isolated from urinary infections than in periurethral strains from healthy individuals: (i) O serogroups 2, 4, 6, 8, 18ab and 75; (ii) high K-antigen titre; (iii) production of haemolysin; (iv) production of fimbriae; (v) fermentation of salicin. The correlation between isolation of a strain from the urinary tract and possession of any single property was not strong; however, strains rich in a combination of these pathogenic properties were rarely isolated from the periurethral area of healthy subjects but were common in urinary infections. Nevertheless, a significant proportion of urinary strains had few pathogenic properties. Strains rich in pathogenic properties were more commonly isolated from upper urinary-tract infections than from lower-tract infections; this indicates that the properties of the invading organism may influence the localisation of infection.

The carriage of Escherichia coli on the peri-urethral area and in the feces in patients on long term low dose cotrimoxazole therapy.

Peri-urethral and fecal carriage of E. coli has been studied in 30 patients maintained on long term low dose cotrimoxazole and in abacteriuric subjects not receiving any antibiotic. Cotrimoxazole treatment is associated with a dramatic reduction in E. coli carriage both in the feces and especially on the peri-urethral area which persists over months or years. Recovery of trimethoprim-resistant E. coli from the feces was uncommon but when observed antedated subsequent relapse due to resistant organisms. Possible mechanisms for low peri-urethral carriage rates include reduction in fecal carriage, vaginal secretion of trimethoprim or low urinary concentrations of that drug.

Periurethral enterobacterial carriage in pathogenesis of recurrent urinary infection.

Periurethral carriage rates of enterobacteria have been studied in 20 normal women, 34 patients between episodes of bacteriuria, 34 patients with the "urethral syndrome," and 15 asymptomatic abacteriuric patients with a previous history of frequency and dysuria.Over a six-week period no difference in the Escherichia coli carriage rate was shown between these four groups. The carriage of all enterobacteria was slightly but significantly (P <0.05) lower in normal women compared with the patient groups but no difference was observed between the latter. There was no difference in the recovery rate and carriage of individual E. coli serotypes between the four groups.It is concluded that the presence of enterobacteria or E. coli on the periurethral area is not the principal determinant factor in the pathogenesis of recurrent urinary tract infection or the urethral syndrome and that definition of carriage status is of little practical value in management.

Long-term control of bacteriuria with trimethoprim-sulphonamide.

Long-term antibacterial therapy with the drug combination trimethoprim-sulphonamide has been used for the treatment of 52 patients with persistent or recurrent bacteriuria. Hypersensitivity or gastrointestinal intolerance was observed in six. Bacteriuria was controlled in 36 out of 38 patients with organisms sensitive to trimethoprim-sulphonamide, 28 having received treatment for periods ranging from 6 to 49 months. Treatment was in some cases curative and in others suppressive or prophylactic. The importance of supportive measures is re-emphasized.