3: Urogenital & Sexually Transmitted Diseases (Chapter 26)

Urinary Tract Infection (UTI)

UTIs can be “ascending” or “descending” depending on where the infection starts in the urinary system. E. coli causes 80% of the UTIs but other fecal enteric organisms such as Proteus and Klebsiella can cause infections. UTIs are often nosocomial infections due to procedures such as catheterization.

Bacterial Vaginitis (Gardnerella vaginalis)

If the pH of the vagina increases a normal flora organism called Gardnerella vaginalis can interact with anaerobic bacteria to cause infection. Vaginal epithelial cells covered with Gardnerella “clue cells” can be seen in a microscope smear and used for diagnosis.

Gonorrhea (Neisseria gonorrhoeae)

Neisseria gonorrhoeae causes the infection. Virulence factors include attachment pili & endotoxin & Opa proteins which suppress T cell activation and an IgA protease. The organism can survive inside polymorphonuclear leukocytes. Humans are the only natural host. It can be transmitted by asymptomatic carriers. The infection can lead to pelvic inflammatory disease (PID) and can disseminate to cause eye infections as discussed previously. The organism can survive in pus for hours and on contaminated objects such as sheets.

Syphilis (Treponema pallidum)

Transmitted sexually or through saliva. The organism rapidly enters the bloodstream. Stages: 1) Incubation. 2) Primary: chancre present. 3) Secondary: organism in circulation causing inflammatory response

Chlamydia Infection (Chlamydia trachomatis)

Caused by the intracellular organism Chlamydia trachomatis. Causes nongonococcal urethritis (NGU) and can lead to pelvic inflammatory disease (PID).

Nongonococcal Urethritis (Mycoplasma genitalium / Mycoplasma hominis)

Mycoplasma genitalium and Mycoplasma hominis can cause NGU. These organisms may colonize the placenta and cause abortions and can lead to PID. Mycoplasma hominis is frequently part of the normal flora.