Voges–Proskauer (VP) Test:It is a test used to detect acetoin in bacterial broth culture. Both Proteus vulgaris and mirabilis are methyl red test positive. Methyl red (MR) Test:The methyl red test is used to identify bacteria to produce pyruvic acid from glucose metabolism. Hanging drop preparation: Actively motile rods observation Such a condition is called the Dienes phenomenon. However, in the case of two identical strains of Proteus, swarming of two coalesce without signs of demarcation. Gram stain: Gram-negative rods which are non-capsulated and non-sporing ( evidence).Ĭulture:Swarming effect over blood agar plate as a consequence of the organisms active motility and NLF colonies on Macconkey agar whereas Blue-gray translucent colonies on CLED agar with fishy or seminal odor.ĭienes phenomenon: When two different strains of Proteus species inoculate at different places of the same non-inhibitory medium (blood agar), swarming of the two strains remains separated by a narrow visible furrow. Specimens collection: The sample should be collected in a sterile container under all aseptic conditions and transported to the laboratory immediately. Midstream urine (MSU) in UTI whereas pus in pyogenic lesions. Specimens: It depends on the site of infection and common samples are urine, pus, and ear discharge. Total three non-motile strains, among them two of Proteus vulgaris OX2, OX19, and one Proteus mirabilis OX K are applicable as the antigens for this test. The sharing of these polysaccharide antigens of Proteus with some rickettsiae forms the basis of the Weil-Felix reaction for the diagnosis of some rickettsial infections. They also noted that certain non-motile strains of Proteus vulgaris, called X strains were agglutinated by sera of typhus patients. WeIl and Felix ( 1966) observed flagellated strains of Proteus grew on agar as a thin surface film (named Hauch) whereas non flagellated variant strains without surface film ( Ohne Hauch). The Proteus possess thermostable, somatic (O), and thermolabile flagellar (H) antigens upon which, several serotypes have been recognized. XLD agar: Proteus produces individual non-lactose fermenting colonies after overnight incubation at 35-37☌ and swarming is prevented due to bile salt present in the medium Antigenic Structure of Proteus MacConkey agar: Proteus produces individual non-lactose fermenting colonies after overnight incubation at 35-37☌ and swarming is prevented due to bile salt present in the medium.ĬLED agar: Blue-gray translucent colonies and absence of swarming are due to electrolyte deficiency. Culture on blood agar shows a characteristics’ fishy or seminal odor’ with swarming growth as shown above picture. Motility is not as easily observed at 35-37 ☌ at room temperature ( 20-28☌).
They are actively motile, non-capsulated, Gram-negative bacilli measuring 1-3µm x 0.5 µm in size. They are opportunist pathogens and may cause many types of infection.