Studies in Urinary Tract Infections

A different prevalence of the most common E. coli O groups in primary and recurrent urinary tract infections has been reported. In the present study 219 non‐pregnant women with bacteriuria were followed up regularly in the Out‐patient Clinic after treatment. Two hundred and fifity‐five cases of reinfection were detected. Seventy‐seven per cent of the infections on admission were due to E. coli. as compared to 78% in reinfections. The proportion of infections due to the most prevalent O groups, 02, 04, 06, 075, was considerably higher on admission (56%) than in the reinfections (34%). This was due to some extent to exclusion of cases of recurrence with organisms identical to those found in the preceding infection. However, the main reason was a decrease in the prevalence of one serotype, E. coli 02:H4, during the observation period. This was probably caused by changes in the flora from which the urinary tract is infected.