Genitourinary infections fall into two main categories: (1) primary infections due to sexually transmitted pathogenic microorganisms and (2) infections due to members of the resident flora. Genital infections are uncommon in children and increase dramatically in sexually active adults, in whom sexually transmitted diseases are the second most prevalent group of reportable communicable illness in North America. Sexually transmitted pathogens include parasites (Trichomonas vaginalis), bacteria (Treponema pallidum, Neisseria gonorrhoeae, Chlamydia trachomatis, Haemophilus ducreyi), and viruses (Herpes simplex virus, human papillomavirus, human immunodeficiency virus). Genital infections due to the fungus Candida albicans or to members of the endogenous bacterial flora (Bacteroides fragilis and members of the family Enterobacteriaceae) are not known to be sexually transmitted. Bacterial vaginosis occurs when the balance of vaginal flora is upset.
The urinary tract and urine are normally sterile. Numerous mechanical and biologic processes ensure that microorganisms do not enter the urinary tract. Women are more susceptible to urinary infections because the female urethra is short and because the area around the urethral opening is colonized with potential pathogens (e.g. E coli and E faecalis).
Copyright © 1996, The University of Texas Medical Branch at Galveston.