HAEMOPHILUS

'''Haemophilus''' is a genus of Gram-negative, pleomorphic, coccobacilli bacteria. Bergey's Manual of Determinative Bacteriology, Holt JG (editor), , , Williams & Wilkins, 1994, ISBN 0-683-00603-7 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 commensal organisms along with some significant pathogenic strains such as ''H. influenzae''—a cause of sepsis and bacterial meningitis in young children—and ''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 serogroups exist, ''a''—''f'' and ''e′''. Haemophilus Species. ''In:'' Baron's Medical Microbiology ''(Barron S ''et al'', eds.), Musher DM, , , Univ of Texas Medical Branch, 1996, (via NCBI Bookshelf) ISBN 0-9631172-1-1 Capsule type ''b'' ('Hib') is the most clinically significant because of its virulence.

Contents

Metabolism

References

External links

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. Sherris Medical Microbiology, Ryan KJ; Ray CG (editors), , , McGraw Hill, 2004, ISBN 0-8385-8529-9 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.

References

External links

★ ''Haemophilus'' chapter in Baron's ''Medical Microbiology'' (online at the NCBI bookshelf).