This differentiation process includes the elongation of the cell 20 to 50 times longer than the vegetative cell, multinucleation, and more than a 50-fold greater surface density of flagella. When Proteus mirabilis encounters a solid surface, and other necessary conditions have been met, the cell will undergo the differentiation process into a swarmer cell. It has been proposed that Proteus mirabilis senses a solid surface by the inhibition of its flagellum rotation, and it is this lack of freely rotating flagella that let the bacteria know it is on a solid surface. Swarming cells are only formed when the bacteria are grown on solid surfaces so the ability to detect these solid surfaces is a required feature. In the vegetative cell the flagella are used to propel the bacterium forward. In liquid culture, Proteus mirabilis exists as a vegetative cell that is approximately 2µm long and has four to ten peritrichous flagella. The swarming capability of Proteus mirabilis is important because it is implicated in the pathogenesis of the bacteria and the swarming capability is associated with the bacteria's ability to express virulence factors Proteus mirabilis has a very characteristic bulls-eye appearance on an agar plate due to the regular periodic cycling between the vegetative and swarming state of the cells. Swarming is a specialized form of motility that groups of multicellular, flagellated bacteria can undergo to expand their populations to new locations. No fermentation of arabinose, sorbitol and dulcitol.Catalase positive and cytochrome oxidase-negative.Methyl red-positive and Voges-Proskauer negative (Can be both MR- and V-P-positive).Indole-negative and nitrate reductase-positive (no gas bubbles produced). This line is named the Dienes line after its discoverer Louis Dienes. This species' ability to inhibit growth of unrelated strains had been a topic for scientific curiosity, which then resulted in the discovery a macroscopically visible line of reduced bacterial growth where two swarming strains intersect. mirabilis is not pathogenic in guinea pigs or chickens. It is commonly found in the human digestive system. It is motile, possessing peritrichous flagella, and is known for its swarming ability. It can produce hydrogen sulfide gas, and forms clear films on growth media. Proteus mirabilis in trypticase soy agar growth media Characteristics mirabilis strains are also resistant to first-generation cephalosporins and ampicillin. mirabilis is generally susceptible to most antibiotics apart from tetracycline and nitrofurantoin, but 10–20% of P. Proteus species can also cause wound infections, sepsis, and pneumonia, mostly in hospitalized patients. Once the stones develop, over time they may grow large enough to cause obstruction and kidney failure. The bacterium can be found throughout the stones, and these bacteria lurking in the kidney stones can reinitiate infection after antibiotic treatment. 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. This rod-shaped bacterium has the ability to produce high levels of urease, which hydrolyzes urea to ammonia (NH 3), so makes the urine more alkaline. mirabilis produces a very distinct fishy odor. It can be diagnosed in the lab due to characteristic swarming motility, and inability to metabolize lactose (on a MacConkey agar plate, for example). Diagnosis Īn alkaline urine sample is a possible sign of P. Proteus mirabilis is most frequently associated with infections of the urinary tract, especially in complicated or catheter-associated urinary tract infections. Proteus mirabilis can migrate across the surface of solid media or devices using a type of cooperative group motility called swarming. It is widely distributed in soil and water. mirabilis causes 90% of all Proteus infections in humans. It shows swarming motility and urease activity. Proteus mirabilis is a Gram-negative, facultatively anaerobic, rod-shaped bacterium. Proteus mirabilis appears as Gram-negative rods after Gram staining under bright-field microscopy with 1000 times magnification.
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