Proteus
Last reviewed: 23.04.2024
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The genus Proteus belongs to the family Enterobacteriaceae and includes three species. Important role in human pathology, especially as agents of purulent inflammatory diseases and food toxic infections, play two types: Proteus vulgaris and Proteus mirabilis.
All representatives of the genus Proteus - gram-negative rods with rounded ends, 0.4-0.6 x 1-3 microns in size, do not form spores and capsules, are peritrichs. These bacteria are prone to polymorphism, coccoid and filamentous forms are observed. Sometimes there are also fixed variants, devoid of flagella (O-form).
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Biochemical properties of proteins
Optional anaerobes, chemoorganotrophs. The temperature optimum is 37 ° C, pH 7.2-7.4; temperature growth limits from 20 to 38 ° C. To nutrient media are undemanding, grow well on simple media. The H-form (flagellate) protea gives on the MPA a characteristic creeping growth in the form of a gentle veil of bluish-smoky color (swarming phenomenon). Creeping growth of the protea is used to isolate a pure culture when sowing by the Shukevich method (the crop is produced into the condensation moisture of freshly cut MPA, the culture of the protein gradually rises in the form of a veil upward along the surface of the medium). The O-form of the protein gives on the MPA large ones with even edges of the colony. On the BCH, a diffuse clouding of the medium with a thick white sediment on the bottom and a soft film on the surface is noted. The O-form of the protein grows on certain nutrient media containing bile acids (Ploskirev's medium); 0.1-0.2% carbolic acid; 5-6% ethanol, dyes, boric acid, detergents. On Ploskirev's medium Proteus gives transparent, delicate, shiny colonies with a characteristic odor, slightly alkaline medium, which is colored around them in a yellowish color. With age, the colony becomes turbid, their center takes on a brown color. Proteium colonies in O-form differ little from colonies of salmonella, which makes their identification difficult. As media of enrichment use Kaufman, Muller's medium, 5% bile broth.
Representatives of the genus Proteus ferment glucose with the formation of acid and a small amount of gas, do not ferment lactose and mannitol, are resistant to cyanide, form urease and phenylalanine deaminase. The species are differentiated by additional biochemical tests.
Antigenic structure of the proteus
Like other flagellar representatives of the enterobacteria family, the proteas distinguish the thermostable somatic O-antigen (49 serotypes) and the flagellum thermolabile H-antigen (19 serotypes). It should be noted the relationship of the somatic antigen of the protein with the antigens of rickettsia (proteic strains of the OX series). According to the antigenic properties of Proteus vulgaris and Proteus, ynirabilis is divided into 110 serotypes.
LPS of the cell wall of the protein is the most important pathogenicity factor that plays the role of endotoxin.
Epidemiology of diseases caused by proteas
Proteas are usually saprophytes of decaying garbage, in small amounts are present in the intestines of animals and humans, are found in sewage and soil. Most often, infection occurs by an alimentary route, when a large number of proteas enter the human body with food. Often, protei can act as a causative agent of dysbiosis (endogenous infection) or as a typical pathogen of hospital infection.
Proteus is relatively stable in the external environment, it is well tolerated by freezing. At a temperature of 60 ° C perished for 1 hour, at 80 ° C - for 5 minutes, in a 1% solution of phenol perishes in 30 minutes. It can be resistant simultaneously to many antibiotics and disinfectants.
Symptoms of diseases caused by proteas
Proteus can cause a person a variety of diseases, often occurring according to the type of food poisoning. In association with other opportunistic microorganisms protey causes various forms of purulent-inflammatory and septic diseases: cystitis, pyelitis, purulent complications of wounds and burn surfaces, phlegmon, abscesses, pleurisy, pneumonia, osteomyelitis, meningitis, sepsis. The pathogenesis of foodborne disease is associated with the massive destruction of the protein in the gastrointestinal tract and the absorption of endotoxin released into the blood. The severity of the disease is directly dependent on the amount of protein that has entered the body.
Laboratory diagnostics of diseases caused by proteas
The bacteriological method is used. The material for sowing is pus, urine, vomit, washing water, blood, cerebrospinal fluid, sputum, pleural effusion, which are sown on differential diagnostic environments (Ploskirev's medium), enrichment medium and MPA by the Shukevich method. The isolated pure culture is identified by biochemical properties, the serovar is determined in the agglutination reaction of live and warm culture with polyvalent and monoreceptor O and H serums. It is also possible to determine the growth of titers of O- and H-antibodies in the agglutination reaction with autostams.
Treatment of diseases caused by proteas
In case of food poisoning caused by the protea, non-specific treatment aimed at detoxification (gastric lavage, copious drinking, etc.) is carried out. In the case of a disease accompanied by suppuration or sepsis, antibiotics are used taking into account the results of the antibioticogram. In colitis associated with intestinal dysbiosis, when protey is present in large quantities, it is advisable to use the intestibacteriophage, which includes the proto phage as well as the proteus or coliprotein bacteriophage, orally. The latter drugs are also effective in local inflammatory processes (purulent complications of wounds, urogenital organs), when they are prescribed in the form of lotions, irrigation, tamponing, and splintering. With slow inflammatory processes, difficult to respond to antibiotic therapy, it is advisable to use autovaccine.