Urinary Tract Infection (UTI)

Most commonly bladder

• Key Pathogens:
  • Escherichia coli is the most common cause.
  • Other less common pathogens include Staphylococcus saprophyticus (especially in sexually active young women), Klebsiella pneumoniae, and Enterococcus faecalis.
• Treatment:
  • Uncomplicated cystitis: Typically treated with antibiotics like nitrofurantoin, trimethoprim-sulfamethoxazole (TMP-SMX), or fosfomycin.
  • Complicated UTI or pyelonephritis: May require broader-spectrum antibiotics such as fluoroquinolones or ceftriaxone.

Urethritis

• Definition: Inflammation of the urethra, often caused by sexually transmitted infections.
• Key Pathogens:
  • Gonococcal urethritis: Caused by Neisseria gonorrhoeae.
  • Nongonococcal urethritis (NGU): Primarily caused by Chlamydia trachomatis and Mycoplasma genitalium.
• Treatment:
  • Gonorrhea: Treated with a combination of ceftriaxone and azithromycin (or doxycycline).
  • Chlamydia: Can be treated with azithromycin or doxycycline.
  • It is crucial to treat sexual partners to prevent reinfection.

Vaginitis

• Key Pathogens & Treatment:

  • Bacterial Vaginosis (BV):

    • Pathogen: An overgrowth of bacteria, most notably Gardnerella vaginalis.
    • Presentation: Thin, grayish-white discharge with a "fishy" odor.
    • Diagnosis: Amsel criteria (requires 3 of 4: characteristic discharge, vaginal pH >4.5, positive whiff test, and clue cells on microscopy).
    • Treatment: Metronidazole or clindamycin.

  • Trichomoniasis:

    • Pathogen: The protozoan Trichomonas vaginalis.
    • Presentation: Malodorous, frothy, yellow-green discharge. May also cause "strawberry cervix" (cervical petechiae).
    • Diagnosis: Wet mount microscopy showing motile trichomonads. NAAT is also an option.
    • Treatment: Metronidazole for the patient and their sexual partner(s).

  • Candidiasis (Yeast Infection):

    • Pathogen: Most commonly Candida albicans.
    • Presentation: Thick, white, "cottage cheese-like" discharge with intense itching.
    • Diagnosis: Normal vaginal pH (4.0-4.5) and pseudohyphae seen on a KOH prep.
    • Treatment: Over-the-counter topical azoles (e.g., clotrimazole, miconazole) or oral fluconazole.