THE PERIURETHRAL AEROBIC FLORA IN GIRLS HIGHLY SUSCEPTIBLE TO URINARY INFECTIONS

Abstract. After the age of 5 years, normal children have but few aerobic gram‐negative rods periurethrally. This study examines whether there is an abnormal periurethral colonization in urinary tract infection‐prone girls during infection‐free intervals, indicating a defective local defence. In 13 girls with a history of recurrent infection, daily bacterial samples were obtained from the periurethral area and from urine. Sampling continued until an infection eventually occurred. Seven girls contracted a urinary tract infection within 3–30 days. All were heavily colonized with gram‐negative rods, often several species, before infection appeared. Serotyping of E. coli confirmed that it was the colonizing strain which later invaded the bladder. The findings suggest a local defect in the antibacterial defence of infection‐prone individuals and gives strong evidence for ascending infection. Six girls remained uninfected during an observation period of 9–123 days. They all had a normal periurethral flora. A reasonable hypothesis would be that the same factor counteracted colonization and infection. Since abnormal periurethral colonization was not a constant phenomenon the postulated defect may vary. This might explain the fact that urinary tract infections often appear in quick succession, often followed by long infection‐free intervals.