Haemophilus 2453105 213969734 2008-05-21T15:58:16Z 138.253.176.6 Add H. somnus {{Taxobox | color = lightgrey | name = ''Haemophilus'' | regnum = [[Bacterium|Bacteria]] | phylum = [[Proteobacteria]] | classis = Gamma Proteobacteria | ordo = [[Pasteurellaceae|Pasteurellales]] | familia = [[Pasteurellaceae]] | genus = '''''Haemophilus''''' | genus_authority = Winslow ''et al.'' 1917 | subdivision_ranks = Species | subdivision = ''[[Haemophilus blue aegyptius|H. aegyptius]]''<br> ''[[Haemophilus aphrophilus|H. aphrophilus]]''<br> ''[[Haemophilus avium|H. avium]]''<br> ''[[Haemophilus ducreyi|H. ducreyi]]''<br> ''[[Haemophilus felis|H. felis]]''<br> ''[[Haemophilus haemolyticus|H. haemolyticus]]''<br> ''[[Haemophilus influenzae|H. influenzae]]''<br> ''[[Haemophilus paracuniculus|H. paracuniculus]]''<br> ''[[Haemophilus parahaemolyticus|H. parahaemolyticus]]''<br> ''[[Haemophilus pittmaniae|H. pittmaniae]]''<br> ''[[Haemophilus somnus|H. somnus]]''<br> etc. }} '''''Haemophilus''''' is a [[genus]] of [[Gram-negative]], [[pleomorphic]], [[coccobacillus|coccobacilli]] [[bacteria]] belonging to the ''[[Pasteurellaceae]]'' family.<ref name=Bergeys>{{cite book | author = Holt JG (editor) | title = Bergey's Manual of Determinative Bacteriology | edition = 9th ed. | publisher = Williams & Wilkins | year = 1994 | id = ISBN 0-683-00603-7 }}</ref><ref name= KuhnertChristensen>{{cite book | author = Kuhnert P; Christensen H (editors). | title = Pasteurellaceae: Biology, Genomics and Molecular Aspects | publisher = Caister Academic Press | year = 2008 | url=http://www.horizonpress.com/past | id = [http://www.horizonpress.com/past ISBN 978-1-904455-34-9 ]}}</ref> While ''Haemophilus'' bacteria are typically small coccobacilli, they are categorized as ''pleomorphic'' bacteria because of the wide range of shapes they occasionally assume. The genus includes [[Commensalism|commensal]] organisms along with some significant [[pathogenic]] strains such as ''[[Haemophilus influenzae|H. influenzae]]''&mdash;a cause of sepsis and bacterial meningitis in young children&mdash;and ''[[Haemophilus ducreyi|H. ducreyi]]'', the causative agent of [[chancroid]]. All members are either aerobic or facultatively anaerobic. ''Haemophilus'' species are classified by characterization of their [[capsule]]: seven [[serogroup]]s exist, ''a''—''f'' and ''e&prime;''.<ref name=Barron>{{cite book | author = Musher DM | title = Haemophilus Species. ''In:'' Baron's Medical Microbiology ''(Barron S ''et al'', eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | id = [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1649 (via NCBI Bookshelf)] ISBN 0-9631172-1-1 }}</ref> Capsule type ''b'' ('''Hib''') is the most clinically significant because of its virulence. ==Metabolism== Members of the ''Haemophilus'' genus are typically cultured on [[blood agar]] plates as all species require at least one of the following blood factors for growth: hemin (factor X) and/or nicotinamide adenine dinucleotide (factor V). [[Chocolate agar]] is an excellent ''Haemophilus'' growth media as it allows for increased accessibility to these factors.<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> Alternatively, ''Haemophilus'' is sometimes cultured using the "Staph streak" technique: both ''Staphylococcus'' and ''Haemophilus'' organisms are cultured together on a single [[blood agar]] plate. In this case, ''Haemophilus'' colonies will frequently grow in small "satellite" colonies around the larger ''Staphylococcus'' colonies because the metabolism of ''Staphylococcus'' produces the necessary blood factor by-products required for ''Haemophilus'' growth. ==See also== * [[Pasteurellaceae]] ==References== <div class="references-small"><references/></div> ==External links== *[http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1641 ''Haemophilus'' chapter] in Baron's ''Medical Microbiology'' (online at the [[National Center for Biotechnology Information|NCBI]] [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=books bookshelf]). [[Category:Proteobacteria]] [[de:Haemophilus]] [[es:Haemophilus]] [[fr:Haemophilus]] [[it:Haemophilus]]