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:
- Cystitis: Nitrofurantoin or TMP-SMX. t
- Pyelonephritis: Fluoroquinolones (Cipro/Levo) or Ceftriaxone.
- Pregnancy: Cephalexin, Amoxicillin-Clavulanate, or Nitrofurantoin.

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:
- Empiric Coverage (Treat for both unless ruled out):
  - Ceftriaxone (IM single dose) for Gonorrhea.
  - PLUS Doxycycline (PO x 7 days) for Chlamydia.
  - Note: Azithromycin is now second-line for Chlamydia due to resistance, but used in pregnancy.

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.