Haemophilus influenzae

Haemophilus influenzae , formerly called bacillus of Pfeiffer , is a Bactérie Pasteurellacae and of the Gamma Proteobacteria. The cells are Coccobacille S or small motionless sticks with negative Gram. It is the doctor Robert Pfeiffer who was the first to describe them in 1892 during the Pandémie of Grippe (= influenza). One a long time believed that he was the person in charge of the influenza, until one highlights in 1933 the viral etiology of the influenza. The Génome is entirely sequence (1 830 140 even basic and 1740 genes).

It is a bacterium isolated starting from the respiratory tracts at the Man.

the form without capsule is Saprophyte of the sphere and can be responsible for local infections (Otite, Sinusite, pharyngitis, Conjonctivite).

Haemophilus influenzae represents meadows of 40% of the bacterial causes of the otitis medias (suppurée infection of the middle ear).

the capsuled form can be responsible for Otite S, of Méningite S, occurring almost exclusively in the children until the 6 years age, of the acute épiglotite which can entraïner death by Asphyxie and which is seen especially in the children, of Septicémie S, Pneumonie S: (The Bronchopneumonie post-grippale was frequently due to the Haemophilus influenzae which however was détronés by the Staphilococca in this demonstration. On the other hand, Haemophilus influenzae frequently remains in question, with the Pneumococcus, in the acute pushes in the bronchitics.)…

Bacteriological characters

Small bacillus with negative Gram. The virulent stocks are frequently encapsulated but the capsule is not easily visible.

Haemophilus influenzae requires 2 growth factors: factors X (hemin) and V (NAD).

On a medium where one deposits a disc containing of factors X+V, the colonies push only around the disc.

Factor X (hemin) can be brought by a medium enriched to blood.

The factor V (NAD) can be brought by:

the addition of yeast extract for example;
or by colonies of gilded Staphilococca.

The camp-test consists in sowing a suspension of Haemophilus on a medium gélosé with blood (factor X) and then to add a scratch of gilded staphilococca (factor V). This induces a typical satellitism, Haemophilus influenzae pushing around the scratch of Staphilococca.

Serotypes

Diseases

See higher (capsuled form) .

Note:

Haemophilus aegyptius is the agent of a Conjonctivite (bacillus of WEEKS).
the Haemophilus para-influenzae requiring only the factor V and the Haemophilus haemoliticus and para-haemoliticus are commensaux mouth which can occasionally be pathogenic.
the Haemophilus aphrophilus, requiring only factor X, can be responsible for Endocardite S and various Suppuration S.

Interactions with Streptococcus pneumoniae

Haemophilus influenzae is often associated with Streptococcus pneumoniae in the infections of the respiratory tracts.

References

Lysenko, E.S., A.J. Ratner, A.L. Nelson, and J.N. Weiser. In near. The role off innate immune responses in the outcome off interspecies competition for colonization off mucosal surfaces. PLoS Pathogens .

External bonds

(in) HiB information one the World Health Organization (WHO) site.
(in) Fact sheet one the CDC site.
(in) Sequence of the genome on the site of TIGR

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