Haemophilus influenzae

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There are a number of different "types", based on the polysaccharide capsule. Sometimes the bacterium has no capsule: such bacteria are referred to as non-typable Haemophilus influenzae (NTHi).


Haemophilus influenzae type B


Haemophilus influenzae type B - an encapsulated bacterium.


H. influenzae is a gram-negative coccobacilus. It does not grow well on blood agar. It will grow on chocolate agar and on plain agar with factor X & factor V discs.


  • Meningitis
  • Lower respiratory tract infections
  • Epiglotitis


Depends on clinical picture.

Blood tests

Blood cultures should be taken in all febrile patients. However, H. influenzae is relatively infrequently isolated in blood cultures. In cases of meningitis, a lumbar puncture (if safe) is required to obtain CSF.



Most strains of H. influenzae will be sensitive to a cephalosporin, many will be sensitive to amoxycillin - physicians should be guided by culture & sensitivity.

Public health action

"Children under 10 years of age who develop invasive Hib disease should also receive rifampicin chemoprophylaxis to eliminate carriage and have Hib antibody levels tested around four weeks after infection. Hib vaccine failure cases should additionally have immunoglobulin concentrations measured and be assessed for evidence of an immune deficiency. If there is a vulnerable individual (child younger than 10 years or an immunosuppressed or asplenic individual of any age) among the household contacts of a case, all members of that household, including the index case, should receive chemoprophylaxis. All children younger than 10 years in the household should be appropriately vaccinated against Hib. Where more than one case occurs in a pre-school or primary school setting, chemoprophylaxis should be offered to all room contacts (including staff), and unimmunised and partially immunised children younger than 10 years should complete their primary immunisations, including a booster dose, as soon as possible. Families of children attending the same pre-school or primary school as an index case should be advised to seek medical advice if their child becomes unwell."[1]


"Hib" vaccine was the first conjugate vaccine licensed in the UK. It has had a dramatic effect on the incidence of Hib disease, although in recent years an increase in cases has been noted. Hence the introduction last year of a booster dose at 12 months of age.

Hib vacination in the UK is now combined with DTP/DTaP-Hib.

A catch-up programme was announced in 2007.[2][3][4]

Post exposure prophylaxis

Chemoprophylaxis and vaccination of contacts may be recommended.[5]

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