Methods for Typing Proteus spp.

Proteus mirabilis HI4320( Genome)

Proteus mirabilis HI4320, complete genome

Protein coding

"Complete genome sequence of uropathogenic Proteus mirabilis,a master of both adherence and motility."

Sanger: Genome Proteus mirabilis strain HI4320

PFGE method

Organism-------------------Proteus mirabilis

Recommended lysis enzyme:proteinase K

Restriction enzyme---------SfiI,NotI

Approximate no. of---------7–10,6–10
restriction Fragments

Fragments size------------50–700,75–700
range (kb)

General Information

Proteus spp.


Characteristics of Proteus Species.

The genus Proteus includes five species, the most common of which are P. mirabilis and P. vulgaris. Proteus species are commonly found in the environment and as normal flora in the intestinal tract of humans and other animals.

Proteus mirabilis, like other members of the Enterobacteriaceae family, is a nonspore-forming, facultative anaerobic, gram-negative bacillus.
Proteus has fimbriae, which facilitate attachment to uroepithelium, and flagellae,which provide the motility required for ascending infection.

Proteus also has the ability to transform from a single cell form to a multicell elongated (swarmer) form. The swarmer cells are more likely to be associated with cellular adherence in the kidney as demonstrated in an animal model of infection.
Hemolysin, which induces cell damage by forming pores, may also play a role in establishment of pyelonephritis.

Diagnosis of a UTI is initially by the urinalysis followed by a culture.


Proteus is easily identified on a MacConkey agar plate as a clear colony (nonlactose fermenter). The obvious swarm seen on blood agar would indicate a Proteus species.

P. mirabilis and P. vulgaris would be indole positivity in the latter.
Proteus species are usually among the most susceptible genera of all of the Enterobacteriaceae, most susceptible to penicillin, although it is not uncommon for them to be resistant to tetracyclines.
Proteus vulgaris, however, tends to be resistant to more antimicrobials than P. mirabilis.

Proteus species produce infections in humans only when the bacteria leave the intestinal tract. They are found in UTIs and produce bacteremia, pneumonia, and focal lesions in debilitated
patients or those receiving intravenous infusions.

Proteus mirabilis is a common cause of UTI. Proteus species produce urease, making urine alkaline and promoting stone formation. The rapid motility of these organisms is evidenced by “swarming” a thin film of organisms over the entire agar plate.
Proteus species produce a urease, which hydrolyzes urealeading to ammonia, which alkalinizes the urine (leading to a higher pH).
Both proteus and E. coli are gram-negative rod bacilli.

genus Proteus

This photograph depicts the colonies of Proteus mirabilis bacteria grown on a Xylose Lysine Sodium Deoxycholate (XLD) agar plate.

P. mirabilis is a Gram-negative bacterium from the family Enterobacteriaceae, and is part of the normal flora of human gastrointestinal tract. However, if this bacterium enters the urinary tract, wounds or lungs it can become pathogenic. Xylose Lyseine (XL) agar is used when trying to culture and isolate Gram-negative enteric bacilli, i.e., rods. When XL agar is supplemented with sodium thiosulfate, ferric ammonium citrate, and sodium deoxycholate, it is then termed XLD agar, and is then an even more selective medium than XL alone. The presence of any black color indicates the deposition of hydrogen sulfide, (H₂S) under alkaline conditions.

Proteus Infection

Proteus species are most commonly found in the human intestinal tract as part of normal human intestinal flora, along with Escherichia coli and Klebsiella species, of which E. coli is the predominant resident.

Proteus is also found in multiple environmental habitats, including long-term care facilities and hospitals. In hospital settings, it is not unusual for gram-negative bacilli to colonize both the skin and oral mucosa of both patients and hospital personnel.

Infection primarily occurs from these reservoirs. However, Proteus species are not the most common cause of nosocomial infections.
Proteus mirabilis causes 90% of Proteus infections and can be considered a community-acquired infection.

Proteus vulgaris and Proteus penneri are easily isolated from individuals in long-term care facilities and hospitals and from patients with underlying diseases or compromised immune systems

Proteus can cause urinary tract infections and hospital-acquired infections. Proteus forms what are known as "swarming colonies" when plated on non-inhibitory media. The most important member of this genus is considered to be Proteus mirabilis, a cause of wound and urinary tract infections.

Fortunately, most strains of Proteus mirabilis are sensitive to ampicillin and cephalosporins. Unlike its relative, Proteus vulgaris is not sensitive to these antibiotics. However, this organism is isolated less often in the laboratory and usually only targets immunosuppressed individuals. Proteus mirabilis and Proteus vulgaris can be differentiated by an indole test for which only Proteus vulgaris tests positive. Proteus vulgaris occurs naturally in the intestines of humans and a wide variety of animals; also manure, soil and polluted waters. is unique, however, because it is highly motile and does not form regular colonies.

Instead,more than 80% of human urinary tract infections (UTI) are due to the bacterium, Escherichia coli, but urinary infections due to Proteus mirabilis are also well documented. Proteus mirabilis once attached to urinary tract, infects the kidney more commonly than E. coli.