Proteus mirabilis is part of the normal flora of the human gastrointestinal tract. It can also be found free living in water and soil. When this organism, however, enters the urinary tract, wounds, or the lungs it can become pathogenic. Proteus mirabilis commonly causes urinary tract infections and the formation of stones.
Proteus mirabilis is part of the Enterobacteriaceae family. It is a small gram-negative bacillus and a facultative anaerobe. Proteus mirabilis is characterized by its swarming motility, its ability to ferment maltose, and its inability to ferment lactose. P. mirabilis has the ability to elongate itself and secrete a polysaccharide when in contact with solid surfaces, making it extremely motile on items such as medical equipment.
The most common infection involving Proteus mirabilis occurs when the bacteria moves to the urethra and urinary bladder. Although Proteus mirabilis mostly known to cause urinary tract infections, the majority of urinary tract infections are due to E. coli. One-hundred thousand cfus per milliliter in the urine are usually indicative of a urinary tract infection. Urinary tract infections caused by P. mirabilis occur usually in patients under long-term catherization. The bacteria have been found to move and create encrustations on the urinary catheters. The encrustations cause the catheter to block.
Symptoms for urethritis are mild including frequency of urination and pyuria (presence of white blob cells in the urine). Cystitis (bladder infection) symptoms are easier to distinguish and include back pain, concentrated appearance, urgency, hematuria (presence of red blood cells in the urine), and suprapubic pain as well as increased frequency of urination and pyuria.
Pyelonephritis (kidney infection) can occur when the bacteria migrates from the lower urinary tract. Although it is seen as a furtherance of infections, not all patients have the symptoms associated with urethritis and cystitis. Pyelonephritis is marked by nausea and vomiting.
Proteus mirabilis can enter the bloodstream through wounds. This happens with contact between the wound and an infected surface. The bacteria induce inflammatory response that can cause sepsis and systemic inflammatory response syndrome (SIRS). SIRS has a mortality rate between 20 and 50 percent.
P. mirabilis can also, though less common, colonize the lungs. This is the result of infected hospital breathing equipment and causes pneumonia. Symptoms for pneumonia include fever, chills, chest pain, rales, and cough.
Prostatitis can occur as a result of P. mirabilis infection,...