Pneumococci

Pneumococci (synonym: Pneumococcus Talamon - Frankel, Streptococcus lanceolatus Pasteur, Micrococcus pneumoniae, Diplococcus pneumoniae Frankel, Streptococcus pneumoniae) is allocated for pneumonia person lantsetolistnyj diplococci. Opened in 1881 Pasteur (L. Pasteur) and independently by Sternberg (G. M. Sternberg) in the USA. Etiological pneumococcus to pneumonia person established Frenkel, Weichselbaum (A. Frankel, A. Weichselbaum) in 1884
Pneumococci, isolated from human or animal,oval or lantsetolistnyj cocci, arranged in pairs; stained gram-positive, the size of about 1 MK. Each pair is surrounded by a thick capsule detected by eosin staining [McKee and poppy-Kartny (I. J. Mackie, J. E. McCartney)]. P. usually grow on artificial nutrient media in the form of chains. Chain in P. usually shorter than that of pyogenic Streptococcus. In cultures P. less lanceolate or more round, fixed and do not form spores. Capsule in P. clearly visible on the preparations of exudates animals and humans, with growth of nutrient mediums, which added blood, serum or ascitic fluid, but not visible when the growth on nutrient mediums. Pneumococci - aerobic or facultative anaerobes, easily coloured normal aniline paints and gram-positive, although become gram in old cultures.
The growth of P. on nutrient mediums scarce, but much better when adding to the medium glucose (0,1%), blood, serum or ascitic fluid. C. grow well in an atmosphere containing 5-10% carbon dioxide. Optimum temperature of growth 37C, maximum 42 degrees, minimum 25 degrees. P. sensitive to changes in the pH of the medium; optimum pH is 7,8, border pH of 6.5, and alkalinity to 8.3. On nutrient agar pneumococci grow, forming a small colonies of up to 1 mm in diameter, delicate, translucent like dewdrops, not merging with each other. Colony P. on a special nutrient medium, for example on blood agar (5%), small, damp, transparent, well demarcated borders, detect alpha-hemolysis, seem to be surrounded greenish discolored area similar to that observed in the increase of blood agar viridans Streptococcus (Streptococcus viridans).
With growth of non-ferrous nutrient media P. ferment carbohydrates with the formation of acid, but without the formation of gas. Fermentation inulin is an important hallmark of pneumococci (viridans streptococci has no ability to decompose inulin). Pneumococci find the ability to quickly autolysis under the action of bile salts. Bile or bile salts dissolved P., which also distinguishes it from Streptococcus.
Pneumococci more sensitive than many other micro-organisms to the bactericidal action of quinine and some of its derivatives. For example, optochin (utilizaciyn) kills P. at a concentration of 1 : 500 000, and streptococci - at a concentration of 1 : 5000.
P. quickly lose their virulence when stored on nutrient mediums, but may persist for months in the cold in dried under vacuum spleen white mouse, died from pneumonia septicemia. The most sensitive P. white mice and rabbits, insensitive Guinea pigs, cats, dogs, chickens and pigeons, vysokorychlostny. P. do not provide true toxin, but forms a hemolysins, active to sheep erythrocytes, Guinea pigs and humans, and hyaluronidase, lincolin and nekrotizirutee substance. The virulence of P. depends not on these toxic entities, and on the presence of a specific soluble substance inherent P. appropriate type.
P. contain multiple antigens. In the depth of microbial cells is nukleoproteidov component associated with the species specificity. Closer to the surface is species-specific polysaccharide (antigen) - somatic antigen immunologically identical in all P. Close to the surface of microbial cells is also typespecific protein (M-specific antigen)similar to M-haemolytic streptococcal antigen. Located poverhnostnye capsule consists, wholly or partly, of polysaccharide, specific to each type of Petrograd, and is closely associated with the virulence of the living germ. This antigen polysaccharide hapten or specific soluble substance (SSS) is typespecific and serves to differentiate immunological types P.
Each type has a different antigenic structure and virulence. P. allocated for pneumonia, are divided on the basis of immunological responses to types I And III, and IV. P. type IV are immunological heterogeneous. This type includes all P., not belonging to the first three types. Typing P. had in its time is due to the fact that the effect of serotherapy pneumonia specific serum was in direct dependence on the type of pathogen.
Microbiological diagnosis of pneumococcal consists of microscopic examination and selection P. on artificial nutrient media. Standard accessory P. determined: reaction swelling capsules reaction microagglutination on glass (method of Sabina) and the macroscopic response agglutination. If for any reason the white mouse cannot be used, sputum or other pathological material inoculated on blood broth with glucose, which is then used as an antigen in the same immunological reactions.
Pneumococcal find on the mucous membranes of the mouth and upper respiratory tract more often than in the human environment. Passed P. airborne. P. IV type are much more common than type I, II and III. Recently sown ity P. sharply decreased with pneumonia, at the same time significantly increased the inoculation of staphylococci. With a substantial reduction of vyciveme pneumococcal and therefore decreasing their value as etiologic agents in greater numbers began to stand out E. coli, enterococci, Proteus and other microorganisms.
Acquired immunity to P. obviously connected with capsular antigen, when immunization which establishes a clear correlation resistance to the response in the form of antibodies to that antigen. Cm. also Bacteria.