The Proteeae are normal fecal flora that often cause infection in patients whose normal flora have been disturbed by antibiotic therapy.
The Proteeae constitute at least 3 genera of gram-negative organisms:
Proteus: P. mirabilis, P. vulgaris, and P. myxofaciens
Morganella: M. morganii
Providencia: P. rettgeri, P. alcalifaciens, and P. stuartii
However, P. mirabilis causes most human infections. These organisms are normal fecal flora and are present in soil and water. They are often present in superficial wounds, draining ears (whether originating in the external, middle, or inner ear), and sputum, particularly in patients whose normal flora has been eradicated by antibiotic therapy. They may cause bacteremia and deep-seated infections, particularly in the ears and mastoid sinuses, peritoneal cavity, and urinary tract of patients with chronic urinary tract infections or with renal or bladder stones; Proteus organisms produce urease, which hydrolyzes urea, leading to alkaline urine and the formation of struvite (magnesium ammonium phosphate) stones.
P. mirabilisP. mirabilis is an emerging problem.
Indole-positive species (P. vulgaris, M. morganii, P. rettgeri
