Haemophilus influenzae: Difference between revisions

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| binomial_authority = (Lehmann & Neumann 1896)<br>Winslow ''et al.'' 1917
| binomial_authority = (Lehmann & Neumann 1896)<br>Winslow ''et al.'' 1917
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{{Hemophilus influenza infection}}
__NOTOC__
{{About0|Haemophilus influenzae infection}}
'''For additional information about other Haemophilus species, click [[Haemophilus|here]].'''<br>
{{CMG}}


==Overview==
==Overview==
Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile [[Gram-negative]] [[coccobacillus]] first described in [[1892]] by [[Richard Friedrich Johannes Pfeiffer|Richard Pfeiffer]] during an [[influenza]] [[pandemic]]. It is generally [[aerobic organism|aerobic]], but can grow as a [[facultative anaerobe]]. ''H. influenzae'' was mistakenly considered to be the cause of the common flu until 1933, when the viral [[etiology]] of the flu became apparent. Still, ''H. influenzae'' is responsible for a wide range of clinical diseases.
Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile [[Gram-negative]] [[coccobacillus]] first described in [[1892]] by [[Richard Friedrich Johannes Pfeiffer|Richard Pfeiffer]] during an [[influenza]] [[pandemic]]. It is generally [[aerobic organism|aerobic]], but can grow as a [[facultative anaerobe]]. ''H. influenzae'' was mistakenly considered to be the cause of the common flu until 1933, when the viral [[etiology]] of the flu became apparent. Still, ''H. influenzae'' is responsible for a wide range of clinical diseases. Because of its small [[genome]], ''H. influenzae'' became the first free-living organism with its entire genome sequenced. Its genome consists of 1,830,140 base pairs of DNA and contains 1740 genes. The method used was [[Whole-genome_shotgun|Whole genome shotgun]]. The sequencing project, completed and published in ''[[Science (journal)|Science]]'' in 1995, was conducted at [[The Institute for Genomic Research]].<ref name="Fleichmann_1995">{{cite journal |author=Fleischmann R, Adams M, White O, Clayton R, Kirkness E, Kerlavage A, Bult C, Tomb J, Dougherty B, Merrick J |title=Whole-genome random sequencing and assembly of Haemophilus influenzae Rd |journal=Science |volume=269 |issue=5223 |pages=496-512 |year=1995 |id=PMID 7542800}}</ref>
 
Because of its small [[genome]], ''H. influenzae'' became the first free-living organism with its entire genome sequenced. Its genome consists of 1,830,140 base pairs of DNA and contains 1740 genes. The method used was [[Whole-genome_shotgun|Whole genome shotgun]]. The sequencing project, completed and published in ''[[Science (journal)|Science]]'' in 1995, was conducted at [[The Institute for Genomic Research]].<ref name=Fleichmann_1995>{{cite journal |author=Fleischmann R, Adams M, White O, Clayton R, Kirkness E, Kerlavage A, Bult C, Tomb J, Dougherty B, Merrick J |title=Whole-genome random sequencing and assembly of Haemophilus influenzae Rd |journal=Science |volume=269 |issue=5223 |pages=496-512 |year=1995 |id=PMID 7542800}}</ref>  


==Serotypes==
==Serotypes==
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==Diseases==
==Diseases==
Most strains of ''H. influenzae'' are opportunistic pathogens - that is, they usually live in their host without causing disease, but cause problems only when other factors (such as a viral infection or reduced immune function) create an opportunity. There are six generally recognized types of ''H. influenzae'': a, b, c, d, e, and f.<ref name=Sherris>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | pages= pp. 396&ndash;401| id = ISBN 0838585299 }}</ref>
Most strains of ''H. influenzae'' are opportunistic pathogens - that is, they usually live in their host without causing disease, but cause problems only when other factors (such as a viral infection or reduced immune function) create an opportunity. There are six generally recognized types of ''H. influenzae'': a, b, c, d, e, and f.<ref name="Sherris">{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | pages= pp. 396&ndash;401| id = ISBN 0838585299 }}</ref>


Naturally-acquired disease caused by ''H. influenzae'' seems to occur in humans only. In infants and young children, ''H. influenzae'' type b (Hib) causes [[bacteremia]], and acute bacterial [[meningitis]]. Occasionally, it causes [[cellulitis]], [[osteomyelitis]], [[epiglottitis]], and joint infections. Due to routine use of the Hib conjugate vaccine in the U.S. since 1990, the incidence of invasive Hib disease has decreased to 1.3/100,000 children. However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where vaccine is not widely used. Unencapsulated ''H. influenzae'' (non-B type) causes ear ([[otitis media]]) and eye ([[conjunctivitis]]) infections and [[sinusitis]] in children, and is associated with [[pneumonia]].
Naturally-acquired disease caused by ''H. influenzae'' seems to occur in humans only. In infants and young children, ''H. influenzae'' type b (Hib) causes [[bacteremia]], and acute bacterial [[meningitis]]. Occasionally, it causes [[cellulitis]], [[osteomyelitis]], [[epiglottitis]], and joint infections. Due to routine use of the Hib conjugate vaccine in the U.S. since 1990, the incidence of invasive Hib disease has decreased to 1.3/100,000 children. However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where vaccine is not widely used. Unencapsulated ''H. influenzae'' (non-B type) causes ear ([[otitis media]]) and eye ([[conjunctivitis]]) infections and [[sinusitis]] in children, and is associated with [[pneumonia]].
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Two scenarios may be responsible for this response:
Two scenarios may be responsible for this response:


# When ''H. influenzae'' is attacked by ''S. pneumoniae'', it signals the immune system to attack the ''S. pneumoniae''
# When ''H. influenzae'' is attacked by ''[[S. pneumoniae]]'', it signals the immune system to attack the ''[[S. pneumoniae]]''
# The combination of the two species together triggers an immune system response that is not set off by either species individually.
# The combination of the two species together triggers an immune system response that is not set off by either species individually.


It is unclear why ''H. influenzae'' is not affected by the immune response.<ref name=Lysenko_2005>{{cite journal |author=Lysenko E, Ratner A, Nelson A, Weiser J |title=The role of innate immune responses in the outcome of interspecies competition for colonization of mucosal surfaces |journal=PLoS Pathog |volume=1 |issue=1 |pages=e1 |year=2005 |id=PMID 16201010}}</ref>
It is unclear why ''H. influenzae'' is not affected by the immune response.<ref name="Lysenko_2005">{{cite journal |author=Lysenko E, Ratner A, Nelson A, Weiser J |title=The role of innate immune responses in the outcome of interspecies competition for colonization of mucosal surfaces |journal=PLoS Pathog |volume=1 |issue=1 |pages=e1 |year=2005 |id=PMID 16201010}}</ref>


==Related Chapters==
==Related Chapters==
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*[[Hib vaccine]]
*[[Hib vaccine]]


==Gallery==
<gallery>
Image: Haemophilus influenzae08.jpeg| Gross pathology of subacute bacterial endocarditis involving mitral valve. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae07.jpeg| Haemophilus influenzae satelliting around Staphylococcus aureus. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae06.jpeg| Blood agar plate culture of Haemophilus influenzae. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae05.jpeg| Photomicrograph of Haemophilus influenzae using immunofluorescence. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae04.jpeg| Brain infected with Gram-negative Haemophilus influenzae bacteria <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae03.jpeg| Photomicrograph reveals Gram-negative rods, and Gram-negative cocci, which were determined to be Haemophilus influenzae, and non-meningococcal Neisseria sp. organisms respectively (1000X mag). <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae02.jpeg| Photograph of Gram-negative Haemophilus influenzae bacteria, which were cultured on chocolate agar medium (10X mag). <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
Image: Haemophilus influenzae01.jpeg| Photomicrograph reveals Gram-negative rods, and Gram-negative cocci, which were determined to be Haemophilus influenzae, and non-meningococcal Neisseria sp. organisms in sample of a transtracheal aspirate (1000x mag). <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
</gallery>
==References==
==References==
<!-- ----------------------------------------------------------
<!-- ----------------------------------------------------------
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* [http://www.hibaction.org Hib Initiative] - from [[Johns Hopkins University]], [[London School of Hygiene & Tropical Medicine]], [[Centers for Disease Control and Prevention|CDC]] & [[World Health Organization|WHO]]
* [http://www.hibaction.org Hib Initiative] - from [[Johns Hopkins University]], [[London School of Hygiene & Tropical Medicine]], [[Centers for Disease Control and Prevention|CDC]] & [[World Health Organization|WHO]]


 
[[Category: Proteobacteria]]
[[Category:Proteobacteria]]
[[Category: Polysaccharide encapsulated bacteria]]
[[Category: Polysaccharide encapsulated bacteria]]
[[Category: Infectious Disease Project]]
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[[es:Haemophilus influenzae]]
[[fr:Haemophilus influenzae]]
[[nl:Haemophilus influenzae]]
[[ja:インフルエンザ菌]]
[[pl:Pałeczka grypy]]
[[pt:Haemophilus influenzae]]
[[fi:Haemophilus influenzae]]
[[sv:Haemophilus influenzae]]
[[zh:流感嗜血桿菌]]
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{{WikiDoc Sources}}
{{WikiDoc Sources}}

Latest revision as of 15:30, 14 June 2017

Haemophilus influenzae
H. influenzae on a blood agar plate.
H. influenzae on a blood agar plate.
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Pasteurellales
Family: Pasteurellaceae
Genus: Haemophilus
Species: H. influenzae
Binomial name
Haemophilus influenzae
(Lehmann & Neumann 1896)
Winslow et al. 1917

Haemophilus influenzae infection Main page

Patient Information

Overview

Causes

Classification

Pneumonia
Bacteremia
Meningitis
Epiglottitis
Cellulitis
arthritis
Otitis media
Conjunctivitis

Pathophysiology

This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see Haemophilus influenzae infection.

For additional information about other Haemophilus species, click here.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative coccobacillus first described in 1892 by Richard Pfeiffer during an influenza pandemic. It is generally aerobic, but can grow as a facultative anaerobe. H. influenzae was mistakenly considered to be the cause of the common flu until 1933, when the viral etiology of the flu became apparent. Still, H. influenzae is responsible for a wide range of clinical diseases. Because of its small genome, H. influenzae became the first free-living organism with its entire genome sequenced. Its genome consists of 1,830,140 base pairs of DNA and contains 1740 genes. The method used was Whole genome shotgun. The sequencing project, completed and published in Science in 1995, was conducted at The Institute for Genomic Research.[1]

Serotypes

In 1930, 2 major categories of H. influenzae were defined: the unencapsulated strains and the encapsulated strains. The pathogenesis of H. influenzae infections is not completely understood, although the presence of the encapsulated type b (Hib) is known to be the major factor in virulence. Their capsule allows them to resist phagocytosis and complement-mediated lysis in the non-immune host. Unencapsulated strains are less invasive, but they are able to induce an inflammatory response that causes disease, such as epiglottitis. Vaccination with Hib conjugate vaccines is effective in preventing infection, and several vaccines are now available for routine use.

Diseases

Most strains of H. influenzae are opportunistic pathogens - that is, they usually live in their host without causing disease, but cause problems only when other factors (such as a viral infection or reduced immune function) create an opportunity. There are six generally recognized types of H. influenzae: a, b, c, d, e, and f.[2]

Naturally-acquired disease caused by H. influenzae seems to occur in humans only. In infants and young children, H. influenzae type b (Hib) causes bacteremia, and acute bacterial meningitis. Occasionally, it causes cellulitis, osteomyelitis, epiglottitis, and joint infections. Due to routine use of the Hib conjugate vaccine in the U.S. since 1990, the incidence of invasive Hib disease has decreased to 1.3/100,000 children. However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where vaccine is not widely used. Unencapsulated H. influenzae (non-B type) causes ear (otitis media) and eye (conjunctivitis) infections and sinusitis in children, and is associated with pneumonia.

Interaction with Streptococcus pneumoniae

Both H. influenzae and S. pneumoniae can be found in the upper respiratory system of humans. A study of competition in a laboratory revealed that, in a petri dish, S. pneumoniae always overpowered H. influenzae by attacking it with a hydrogen peroxide and stripping off the surface molecules H. influenzae needs for survival.

When both bacteria are placed together into a nasal cavity, within 2 weeks, only H. influenzae survives. When both are placed separately into a nasal cavity, each one survives. Upon examining the upper respiratory tissue from mice exposed to both bacteria species, an extraordinarily large number of neutrophils immune cells were found. In mice exposed to only one bacteria, the cells were not present.

Lab tests showed that neutrophils exposed to dead H. influenzae were more aggressive in attacking S. pneumoniae than unexposed neutrophils. Exposure to dead H. influenzae had no effect on live H. influenzae.

Two scenarios may be responsible for this response:

  1. When H. influenzae is attacked by S. pneumoniae, it signals the immune system to attack the S. pneumoniae
  2. The combination of the two species together triggers an immune system response that is not set off by either species individually.

It is unclear why H. influenzae is not affected by the immune response.[3]

Related Chapters

Gallery

References

  1. ↑ Fleischmann R, Adams M, White O, Clayton R, Kirkness E, Kerlavage A, Bult C, Tomb J, Dougherty B, Merrick J (1995). "Whole-genome random sequencing and assembly of Haemophilus influenzae Rd". Science. 269 (5223): 496–512. PMID 7542800.
  2. ↑ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. pp. pp. 396&ndash, 401. ISBN 0838585299.
  3. ↑ Lysenko E, Ratner A, Nelson A, Weiser J (2005). "The role of innate immune responses in the outcome of interspecies competition for colonization of mucosal surfaces". PLoS Pathog. 1 (1): e1. PMID 16201010.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 "Public Health Image Library (PHIL)".

External Links


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