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.

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.