pneumococcus

pneumococcus
—pneumococcal /nooh'meuh kok"euhl, nyooh'-/, pneumococcic /nooh'meuh kok"sik, nyooh'-/, pneumococcous /nooh'meuh kok"euhs, nyooh'-/, adj.
/nooh'meuh kok"euhs, nyooh'-/, n., pl. pneumococci /-kok"suy, -see/.
a bacterium, Diplococcus pneumoniae, causing lobar pneumonia and associated with cerain other diseases, as pericarditis and meningitis.
[1885-90; < NL; see PNEUMO-, -COCCUS]

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Spheroidal bacterium (Streptococcus pneumoniae) that causes human diseases including pneumonia, sinusitis, ear infection, and meningitis.

Usually occurring in the upper respiratory tract, this gram-positive (see gram stain) coccus is often found in a chain configuration and surrounded by a polysaccharide capsule. Pneumococci are separated into types depending on the specific capsular polysaccharide formed. Their disease-causing ability resides in the capsule, which delays or prevents their destruction by cells in the bloodstream that normally engulf foreign material.

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 (Streptococcus pneumoniae), spheroidal bacterium in the family Streptococcaceae that causes human diseases such as pneumonia, sinusitis, otitis media, and meningitis. It is microbiologically characterized as a gram-positive coccus, 0.5 to 1.25 μm (micrometre; 1 μm = 10-6 metre) in diameter, often found in a chain configuration and surrounded by a capsule consisting of complex carbohydrate (polysaccharide). Many serological types have been differentiated. Pneumococci normally occur in the upper respiratory tract.

      Pneumococci have proved useful in elucidating microbial genetics. The phenomenon of transformation—an alteration of one cell by another—was first observed in these organisms in 1928. Colonies formed by pneumococci usually are small, round, and smooth. Occasional mutant rough colonies are produced by organisms that cannot synthesize the capsular material. When a rough colony is grown in the presence of genetic material (deoxyribonucleic acid) from a smooth colony, the rough colony is transformed into a smooth one.

      Pneumococci are separated into types depending on the specific capsular polysaccharide formed. The disease-causing ability of pneumococci resides in the capsule, which delays or prevents their destruction by phagocytes, cells in the bloodstream that normally engulf foreign material.

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Universalium. 2010.

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Look at other dictionaries:

  • Pneumococcus — Pneu mo*coc cus, n. [See {Pneumo }, and {Coccus}.] (Biol.) A form of micrococcus found in the sputum (and elsewhere) of persons suffering with pneumonia, and thought to be the cause of this disease. [1913 Webster] …   The Collaborative International Dictionary of English

  • Pneumococcus — Pneumococcus, Vulgärname des als Erreger der Lungenentzündung angesehenen Bacterium pneumoniae Mig …   Meyers Großes Konversations-Lexikon

  • pneumococcus — ► NOUN (pl. pneumococci) ▪ a bacterium associated with pneumonia and some forms of meningitis. DERIVATIVES pneumococcal adjective …   English terms dictionary

  • pneumococcus — [no͞o΄mō käk′əs, nyo͞o΄mō käk′əs] n. pl. pneumococci [no͞o΄mōkäk′sī΄, nyo͞o΄mōkäk′sī΄] [ModL: see PNEUMO & COCCUS] a bacterium (Streptococcus pneumoniae) that is a cause of certain diseases, as pneumonia pneumococcal [no͞o΄mōkäk′əl,… …   English World dictionary

  • Pneumococcus (Streptococcus pneumoniae) — A type of bacterium that comes in pairs and is shaped like a lancet (a surgical knife with a short wide two edged blade). Pneumococcus is the leading cause of bacterial pneumonia and otitis media (middle ear infections) and an important… …   Medical dictionary

  • pneumococcus — noun (plural pneumococci) Etymology: New Latin Date: 1890 a bacterium (Streptococcus pneumoniae) that causes an acute pneumonia involving one or more lobes of the lung • pneumococcal adjective …   New Collegiate Dictionary

  • pneumococcus — noun A gram positive bacterium, Streptococcus pneumoniae, that causes pneumonia and other infectious diseases See Also: coccus …   Wiktionary

  • pneumococcus — SYN: Streptococcus pneumoniae. [G. pneumon, lung, + kokkos, berry (coccus)] Fraenkel p. SYN: Streptococcus pneumoniae. * * * pneu·mo·coc·cus .n(y)ü mə käk əs n, pl coc·ci käk .(s)ī a bacterium of the genus Streptococcus (S. pneumoniae …   Medical dictionary

  • Pneumococcus — Pneu|mococcus vgl. Pneumokokkus …   Das Wörterbuch medizinischer Fachausdrücke

  • pneumococcus — n. bacteria that causes pneumonia nuːməʊ kÉ‘kÉ™s / njuːməʊ kÉ’k …   English contemporary dictionary

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