Streptococcus pneumoniae infection overview: Difference between revisions

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==Overview==
==Overview==
'''''Streptococcus pneumoniae''''', or '''pneumococcus''', is a [[Gram-positive]], [[Hemolysis (microbiology)|alpha-hemolytic]] diplococcus [[bacterium]] and a member of the [[genus]] ''[[Streptococcus]]''.<ref name=Sherris>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | id = ISBN 0-8385-8529-9 }}</ref> A significant human [[pathogen]], ''S. pneumoniae'' was recognized as a major cause of [[pneumonia]] in the late 19th century and is the subject of many [[humoral immunity]] studies.


Despite the name, the organism causes many types of infection other than [[pneumonia]], including [[acute sinusitis]], [[otitis media]], [[meningitis]], [[osteomyelitis]], [[septic arthritis]], [[endocarditis]], [[peritonitis]], [[pericarditis]], [[cellulitis]], and [[brain abscess]].
''S. pneumoniae'' is the most common cause of bacterial meningitis in adults and children, and is one of the top two isolates found in otitis media.<ref>{{cite journal |author=Dagan R |title=Treatment of acute otitis media - challenges in the era of antibiotic resistance |journal=Vaccine |volume=19 Suppl 1 |issue= |pages=S9-S16 |year= |pmid=11163457}}</ref> Pneumococcal pneumonia is more common in the very young and the very old.
''S. pneumoniae'' can be differentiated from ''[[Streptococcus viridans]]'', which is also alpha hemolytic, using an [[optochin]] test, as ''S. pneumoniae'' is optochin sensitive. The encapsulated, gram-positive coccoid bacteria have a distinctive morphology on gram stain, the so-called, "lancet shape." It has a polysaccharide capsule that acts as a virulence factor for the organism; 91 different capsular types are known, and these types differ in virulence, prevalence, and extent of drug resistance.


==References==
==References==

Revision as of 17:40, 2 February 2012

Template:Streptococcus pneumoniae Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, alpha-hemolytic diplococcus bacterium and a member of the genus Streptococcus.[1] A significant human pathogen, S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century and is the subject of many humoral immunity studies.

Despite the name, the organism causes many types of infection other than pneumonia, including acute sinusitis, otitis media, meningitis, osteomyelitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis, and brain abscess.

S. pneumoniae is the most common cause of bacterial meningitis in adults and children, and is one of the top two isolates found in otitis media.[2] Pneumococcal pneumonia is more common in the very young and the very old.

S. pneumoniae can be differentiated from Streptococcus viridans, which is also alpha hemolytic, using an optochin test, as S. pneumoniae is optochin sensitive. The encapsulated, gram-positive coccoid bacteria have a distinctive morphology on gram stain, the so-called, "lancet shape." It has a polysaccharide capsule that acts as a virulence factor for the organism; 91 different capsular types are known, and these types differ in virulence, prevalence, and extent of drug resistance.

References

  1. Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.
  2. Dagan R. "Treatment of acute otitis media - challenges in the era of antibiotic resistance". Vaccine. 19 Suppl 1: S9–S16. PMID 11163457.


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