Differential Diagnosis for Gram Negative Rod from Genitourinary

• Single most likely diagnosis
  • Escherichia coli (E. coli): This is the most common cause of urinary tract infections (UTIs) and is a gram-negative rod. It is commonly found in the gastrointestinal tract and can easily contaminate the genitourinary system.
• Other Likely diagnoses
  • Klebsiella pneumoniae: Another common cause of UTIs, especially in individuals with underlying medical conditions or those who are immunocompromised. It is known for its resistance to various antibiotics.
  • Proteus mirabilis: Often associated with UTIs, particularly in patients with urinary catheters or structural abnormalities of the urinary tract. It can produce urease, leading to the formation of kidney stones.
  • Pseudomonas aeruginosa: Although less common than E. coli, it can cause UTIs, especially in hospitalized patients or those with compromised immune systems.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Neisseria gonorrhoeae: A sexually transmitted infection that can cause severe complications if not treated promptly, including infertility and increased risk of HIV transmission.
  • Yersinia pestis (Plague): Although extremely rare, it can present with symptoms that might initially suggest a UTI. Missing this diagnosis could be fatal due to its high mortality rate if not treated early.
• Rare diagnoses
  • Burkholderia pseudomallei (Melioidosis): A rare but potentially life-threatening infection more commonly associated with pneumonia or skin infections, but can occasionally present as a UTI in endemic areas.
  • Francisella tularensis (Tularemia): Another rare infection that can have a wide range of presentations, including a UTI, though it's more commonly associated with skin, eye, or respiratory infections.