Proteus mirabilis

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Proteus mirabilis
Proteus mirabilis 01.jpg
P. mirabilis on an XLD agar plate.
Scientific classification
P. mirabilis
Binomial name
Proteus mirabilis
Hauser 1885
Proteus mirabilis appears as Gram-negative rods after Gram staining under bright-field microscopy with 1000 times magnification. Proteus mirabilis.jpg
Proteus mirabilis appears as Gram-negative rods after Gram staining under bright-field microscopy with 1000 times magnification.

Proteus mirabilis is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It shows swarming motility and urease activity. P. mirabilis causes 90% of all Proteus infections in humans. It is widely distributed in soil and water. [1]

An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present.

Swarming motility rapid and coordinated translocation of a bacterial population across solid or semi-solid surfaces

Swarming motility is a rapid and coordinated translocation of a bacterial population across solid or semi-solid surfaces, and is an example of bacterial multicellularity and swarm behaviour. Swarming motility was first reported by Jorgen Henrichsen and has been mostly studied in genus Serratia, Salmonella, Aeromonas, Bacillus, Yersinia, Pseudomonas, Proteus, Vibrio and Escherichia.

Urease enzyme

Ureases, functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous bacteria, fungi, algae, plants, and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-containing metalloenzymes of high molecular weight.



An alkaline urine sample is a possible sign of P. mirabilis. It can be diagnosed in the lab due to characteristic swarming motility, and inability to metabolize lactose (on a MacConkey agar plate, for example). Also P. mirabilis produces a very distinct fishy odor.

Urine Liquid by-product of metabolism in the bodies of many animals, including humans

Urine is a liquid by-product of metabolism in humans and in many animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra.

Lactose chemical compound

Lactose is a disaccharide. It is a sugar composed of galactose and glucose and has the formula C12H22O11. Lactose makes up around 2–8% of milk (by weight). The name comes from lac (gen. lactis), the Latin word for milk, plus the suffix -ose used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry.

MacConkey agar culture medium used in microbiology

MacConkey agar is an indicator, a selective and differential culture medium for bacteria designed to selectively isolate Gram-negative and enteric bacilli and differentiate them based on lactose fermentation. The crystal violet and bile salts inhibit the growth of Gram-positive organisms which allows for the selection and isolation of gram-negative bacteria. Enteric bacteria that have the ability to ferment lactose can be detected using the carbohydrate lactose, and the pH indicator neutral red.


This rod-shaped bacterium has the ability to produce high levels of urease, which hydrolyzes urea to ammonia (NH3), so makes the urine more alkaline. If left untreated, the increased alkalinity can lead to the formation of crystals of struvite, calcium carbonate, and/or apatite, which can result in kidney stones. The bacterium can be found throughout the stones, and these bacteria lurking in the kidney stones can reinitiate infection after antibiotic treatment. Once the stones develop, over time they may grow large enough to cause obstruction and renal failure. Proteus species can also cause wound infections, sepsis, and pneumonia, mostly in hospitalized patients. [2]

Ammonia Chemical compound of nitrogen ad hydrogen

Ammonia is a compound of nitrogen and hydrogen with the formula NH3. The simplest pnictogen hydride, ammonia is a colourless gas with a characteristic pungent smell. It is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Ammonia is named for the Ammonians, worshipers of the Egyptian god Amun, who used ammonium chloride in their rituals.

Crystal solid material whose constituent atoms, molecules, or ions are arranged in an ordered pattern extending in all three spatial dimensions

A crystal or crystalline solid is a solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification.

Struvite phosphate mineral

Struvite (magnesium ammonium phosphate) is a phosphate mineral with formula: NH4MgPO4·6H2O. Struvite crystallizes in the orthorhombic system as white to yellowish or brownish-white pyramidal crystals or in platey mica-like forms. It is a soft mineral with Mohs hardness of 1.5 to 2 and has a low specific gravity of 1.7. It is sparingly soluble in neutral and alkaline conditions, but readily soluble in acid.


P. mirabilis is generally susceptible to most antibiotics apart from tetracycline and nitrofurantoin, [3] but 1020% of P. mirabilis strains are also resistant to first-generation cephalosporins and ampicillin. [4]

Antibiotic drug used in the treatment and prevention of bacterial infections

An antibiotic is a type of antimicrobial substance active against bacteria and is the most important type of antibacterial agent for fighting bacterial infections. Antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza; drugs which inhibit viruses are termed antiviral drugs or antivirals rather than antibiotics.

Tetracycline chemical compound

Tetracycline, sold under the brand name Sumycin among others, is an antibiotic used to treat a number of infections. This includes acne, cholera, brucellosis, plague, malaria, and syphilis. It is taken by mouth.

Nitrofurantoin pharmaceutical drug

Nitrofurantoin, sold under the trade name Macrobid among others, is an antibiotic used to treat bladder infections. It is not effective for kidney infections. It is taken by mouth.


P. mirabilis can use urea. It can produce hydrogen sulfide gas, and forms clear films on growth media. It is motile, possessing peritrichous flagella, and is known for its swarming ability. It is commonly found in the human digestive system. P. mirabilis is not pathogenic in guinea pigs or chickens. Noteworthy[ to whom? ] is the ability of this species to inhibit growth of unrelated strains, resulting in a macroscopically visible line of reduced bacterial growth where two swarming strains intersect. This line is named the Dienes line after its discoverer Louis Dienes.

Hydrogen sulfide Poisonous, corrosive and flammable gas

Hydrogen sulfide is the chemical compound with the formula H
. It is a colorless chalcogen hydride gas with the characteristic foul odor of rotten eggs. It is very poisonous, corrosive, and flammable.

Motility Ability to move spontaneously and actively, consuming energy in the process

Motility is the ability of an organism to move independently, using metabolic energy. This is in contrast to mobility, which describes the ability of an object to be moved. Motility is genetically determined, but may be affected by environmental factors. For instance, muscles give animals motility but the consumption of hydrogen cyanide would adversely affect muscle physiology, causing them to stiffen, leading to rigor mortis. In addition to animal locomotion, most animals are motile – the term applies to bacteria and other microorganisms, and to some multicellular organisms, as well as to some mechanisms of fluid flow in multicellular organs and tissue. Motile marine animals are commonly called free-swimming, and motile non-parasitic organisms are called free-living.

Guinea pig domesticated rodent species from South America

The guinea pig or domestic guinea pig, also known as cavy or domestic cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family Suidae, nor do they come from Guinea in Africa, and the origin of their name is still unclear; they originated in the Andes of South America and studies based on biochemistry and hybridization suggest they are domesticated descendants of a closely related species of cavy such as C. tschudii, and therefore do not exist naturally in the wild.

The micro-organism tests:

Indole chemical compound

Indole is an aromatic heterocyclic organic compound with formula C8H7N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin.

Nitrate reductase

Nitrate reductases are molybdoenzymes that reduce nitrate to nitrite. This reaction is critical for the production of protein in most crop plants, as nitrate is the predominant source of nitrogen in fertilized soils.

Methyl red chemical compound

Methyl red, also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder. Methyl red is a pH indicator; it is red in pH under 4.4, yellow in pH over 6.2, and orange in between, with a pKa of 5.1. Murexide and methyl red are investigated as promising enhancers of sonochemical destruction of chlorinated hydrocarbon pollutants. Methyl red is classed by the IARC in group 3 - unclassified as to carcinogenic potential in humans.

Related Research Articles

Urea breath test

The urea breath test is a rapid diagnostic procedure used to identify infections by Helicobacter pylori, a spiral bacterium implicated in gastritis, gastric ulcer, and peptic ulcer disease. It is based upon the ability of H. pylori to convert urea to ammonia and carbon dioxide. Urea breath tests are recommended in leading society guidelines as a preferred non-invasive choice for detecting H. pylori before and after treatment.

<i>Proteus vulgaris</i> species of bacterium

Proteus vulgaris is a rod-shaped, nitrate-reducing, indole+ and catalase-positive, hydrogen sulfide-producing, Gram-negative bacterium that inhabits the intestinal tracts of humans and animals. It can be found in soil, water, and fecal matter. It is grouped with the Enterobacteriaceae and is an opportunistic pathogen of humans. It is known to cause wound infections and other species of its genera are known to cause urinary tract infections.

<i>Acinetobacter</i> genus of bacteria

Acinetobacter is a genus of Gram-negative bacteria belonging to the wider class of Gammaproteobacteria. Acinetobacter species are oxidase-negative, exhibit twitching motility, and occur in pairs under magnification.

<i>Proteus</i> (bacterium) genus of bacteria

Proteus is a genus of Gram-negative Proteobacteria. Proteus bacilli are widely distributed in nature as saprophytes, being found in decomposing animal matter, sewage, manure soil, the mammalian intestine, and human and animal feces. They are opportunistic pathogens, commonly responsible for urinary and septic infections, often nosocomial.

Cefazolin chemical compound

Cefazolin, also known as cefazoline and cephazolin, is an antibiotic used for the treatment of a number of bacterial infections. Specifically it is used to treat cellulitis, urinary tract infections, pneumonia, endocarditis, joint infection, and biliary tract infections. It is also used to prevent group B streptococcal disease around the time of delivery and before surgery. It is typically given by injection into a muscle or vein.

<i>Staphylococcus epidermidis</i> species of bacterium

Staphylococcus epidermidis is a Gram-positive bacterium, and one of over 40 species belonging to the genus Staphylococcus. It is part of the normal human flora, typically the skin flora, and less commonly the mucosal flora. It is a facultative anaerobic bacteria. Although S. epidermidis is not usually pathogenic, patients with compromised immune systems are at risk of developing infection. These infections are generally hospital-acquired. S. epidermidis is a particular concern for people with catheters or other surgical implants because it is known to form biofilms that grow on these devices. Being part of the normal skin flora, S. epidermidis is a frequent contaminant of specimens sent to the diagnostic laboratory.

Antibiotic sensitivity The susceptibility of bacteria to antibiotics

Antibiotic sensitivity or antibiotic susceptibility is the susceptibility of bacteria to antibiotics. Because susceptibility can vary even within a species, antibiotic susceptibility testing (AST) is usually carried out to determine which antibiotic will be most successful in treating a bacterial infection in vivo. Testing for antibiotic sensitivity is often done by the Kirby-Bauer method. Small wafers containing antibiotics are placed onto a plate upon which bacteria are growing. If the bacteria are sensitive to the antibiotic, a clear ring, or zone of inhibition, is seen around the wafer indicating poor growth. Other methods to test antimicrobial susceptibility include the Stokes method, Etest, Agar and Broth dilution methods for minimum inhibitory concentration (MIC) determination. The results of the test are reported on the antibiogram.

Stenotrophomonas maltophilia is an aerobic, nonfermentative, Gram-negative bacterium. It is an uncommon bacterium and human infection is difficult to treat. Initially classified as Bacterium bookeri, then renamed Pseudomonas maltophilia, S. maltophilia was also grouped in the genus Xanthomonas before eventually becoming the type species of the genus Stenotrophomonas in 1993.

Mezlocillin chemical compound

Mezlocillin is a broad-spectrum penicillin antibiotic. It is active against both Gram-negative and some Gram-positive bacteria. Unlike most other extended spectrum penicillins, it is excreted by the liver, therefore it is useful for biliary tract infections, such as ascending cholangitis.

Aeromonas veronii is a Gram-negative, rod-shaped bacterium found in fresh water and in association with animals. It can be a pathogen of humans and a beneficial symbiont of leeches. In humans A. veronii can cause diseases ranging from wound infections and diarrhea to septicemia in immunocompromised patients. Humans treated with medicinal leeches after vascular surgery can be at risk for infection from A. veronii and are commonly placed on prophylactic antibiotics. Most commonly ciprofloxacin is used but there have been reports of resistant strains leading to infection. In leeches, this bacterium is thought to function in the digestion of blood, provision of nutrients, or preventing other bacteria from growing.

Klebsiella oxytoca is a Gram-negative, rod-shaped bacterium that is closely related to K. pneumoniae, from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate.

<i>Elizabethkingia meningoseptica</i> species of bacterium

Elizabethkingia meningoseptica is a gram-negative rod-shaped bacterium widely distributed in nature. It may be normally present in fish and frogs; while it may be isolated from chronic infectious states, as in the sputum of cystic fibrosis patients. In 1959, the American bacteriologist Elizabeth O. King was studying unclassified bacteria associated with pediatric meningitis at the Centers for Disease Control and Prevention in Atlanta, when she isolated an organism that she named Flavobacterium meningosepticum. In 1994, it was reclassified in the genus Chryseobacterium and renamed Chryseobacterium meningosepticum(chryseos = "golden" in Greek, so Chryseobacterium means a golden/yellow rod similar to Flavobacterium). In 2005, a 16S rRNA phylogenetic tree of Chryseobacteria showed that C. meningosepticum along with C. miricola were close to each other but outside the tree of the rest of the Chryseobacteria and were then placed in a new genus Elizabethkingia named after the original discoverer of F. meningosepticum.

<i>Mycobacterium cosmeticum</i> species of bacterium

Mycobacterium cosmeticum is a rapidly growing mycobacterium that was first isolated from cosmetic patients and sites performing cosmetic procedures.

<i>Proteus penneri</i> species of bacterium

Proteus penneri is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. It is an invasive pathogen and a cause of nosocomial infections of the urinary tract or open wounds. Pathogens have been isolated mainly from the urine of patients with abnormalities in the urinary tract, and from stool. P. penneri strains are naturally resistant to numerous antibiotics, including penicillin G, amoxicillin, cephalosporins, oxacillin, and most macrolides, but are naturally sensitive to aminoglycosides, carbapenems, aztreonam, quinolones, sulphamethoxazole, and co-trimoxazole. Isolates of P. penneri have been found to be multiple drug-resistant (MDR) with resistance to six to eight drugs. β-lactamase production has also been identified in some isolates.

Providencia rettgeri, is a Gram negative bacterium that is commonly found in both water and land environments. P. rettgeri is in the genus Providencia, along with Providencia stuartii, Providencia alcalifaciens, and Providencia rustigianii. P. rettgeri can be incubated at 37 °C in nutrient agar or nutrient broth. It was first discovered in 1904 after a waterfowl epidemic. Strains of the species have also been isolated from nematodes of the Heterorhabditis genus.

<i>Achromobacter xylosoxidans</i> species of bacterium

Achromobacter xylosoxidans is a Gram-negative, aerobic, oxidase and catalase-positive, motile bacterium with peritrichous flagella, from the genus Achromobacter. It is generally found in wet environments. Achromobacter xylosoxidans can cause infections such as bacteremia, especially in patients with cystic fibrosis. In 2013, the complete genome of an A. xylosoxidans strain from a patient with cystic fibrosis was sequenced.

Corynebacterium urealyticum is a bacterial species of the Corynebacterium genus. It is not commonly found in healthy people. It is, however, an important isolate when found in conjunction with a urinary tract infection. In contrast to acid-producing bacteria like Escherichia coli, C. urealyticum, as the name implies, secretes urease enzyme which is strong enough to make urine alkaline. This can lead to the formation of struvite calculi or renal stones. Risk factors associated with this bacterium include immunosuppression, underlying genitourinary disorders, and antibiotic therapy. There are other urease-producing corynebacteria that are associated with urinary tract infections, but C. urealyticum is the most common.

Bacillus fastidiosus is an aerobic, motile, rod-shaped bacterium that has been isolated from soil and poultry litter. The species was first isolated and described by the scientist Den Dooren de Jong in 1929. This organism is a mesophile that contains ellipsoidal spores that do not cause swelling of the sporangia. Bacillus fastidiosus is only able to grow in the presence of uric acid, allantoin, or allantoic acid.


    • Bacteria of the species Proteus mirabilis are widely distributed in soil and water in the natural environment. In humans, Proteus is found as part of the normal flora of the gut....from BioMedHTC Archived 26 September 2009 at the Wayback Machine
  1. Proteus mirabilis and Urinary Tract Infection .
  2. O'hara CM, Brenner FW, Miller JM. Classification, identification, and clinical significance of Proteus, Providencia, and Morganella. Clin Microbiol Rev. 2000;13(4):534-46. .
  3. Gonzalez, Gus; et al. "Proteus Infections Medication". Medscape. Retrieved 30 October 2015.

Further reading