Microbiology | Proteus

Proteus species, specifically *Proteus mirabilis* and *Proteus vulgaris*, are gram-negative, urease-positive bacilli primarily responsible for urinary tract infections. These bacteria utilize the enzyme urease to hydrolyze urea into ammonia, which alkalinizes the urine and creates an environment conducive to the formation of radiopaque struvite kidney stones, often presenting as staghorn calculi. Clinical diagnosis relies on identifying symptoms like dysuria and flank pain alongside laboratory findings such as swarming motility on agar and alkaline urine pH. While *E. coli* remains a common differential, it lacks urease activity. Treatment strategies vary by patient status, utilizing trimethoprim-sulfamethoxazole or nitrofurantoin for uncomplicated cases, while pregnant patients require safer alternatives like cephalosporins. Effective management is critical to prevent complications such as urosepsis and chronic stone formation.