THE PERIURETHRAL AEROBIC BACTERIAL FLORA IN HEALTHY BOYS AND GIRLS

Abstract

The presence of bacterial flora in the periurethral region of healthy children and its variation with age and sex was investigated to provide a basis for subsequent studies in individuals prone to urinary tract infection. Quantitative methods were used for bacterial sampling and culture. The study included 394 girls and 305 boys from birth to 16 yr. During the 1st few weeks of life a massive aerobic bacterial flora (Escherichia coli, enterococci, staphylococci) was established in the periurethral region of both sexes. The colonization with E. coli and enterococci began to diminish during the 1st yr of life and became very scanty after the age of 5 yr. In newborns E. coli colonization was dense in boys and scanty in girls. Later E. coli was the dominating gram-negative species in girls of all age groups. In boys E. coli dominated during the 1st half yr of life; later Proteus was as common as E. coli; and staphylococci did not change very much. Urine samples from healthy school-children contained very few gram-negative bacteria, even when collected without preceding cleansing. There might be a local defense mechanism maturing during the 1st year of life, eventually protecting the exposed area from colonization with gram-negatives and enterococci.