Haemophilus influenzae infections

[Sommer]

Haemophilus influenzae are gram-negative bacteria that can cause infection in the respiratory tract, which can spread to other organs.

Infection is spread through sneezing, coughing, or touching.
The bacteria can cause middle ear infections, sinusitis, and more serious infections, including meningitis and epiglottitis, as well as respiratory infections.
Identifying the bacteria in a sample taken from blood or from infected tissue confirms the diagnosis.
Children are routinely given a vaccine that effectively prevents infections due to Haemophilus influenzae type b.
Infections are treated with antibiotics given by mouth or, for serious infections, intravenously.

(See also Overview of Bacteria.)
Many species of Haemophilus normally reside in the upper airways of children and adults and rarely cause disease. One species causes chancroid, a sexually transmitted disease. Other species cause infections of heart valves (endocarditis) and, rarely, collections of pus (abscesses) in the brain, lungs, and liver. The species responsible for the most infections is Haemophilus influenzae.
Haemophilus influenzae can cause infections in children and sometimes in adults.
Risk of getting a Haemophilus influenzae infection is increased in the following:

Children (particularly boys)
Blacks
Native Americans
People who attend or work at a day care center
People who live in overcrowded conditions
People with an immunodeficiency disorder, no spleen, or sickle cell disease

Infection is spread by sneezing, coughing, or touching infected people.
One type of Haemophilus influenzae, called type b, is more likely to cause serious infections.
In children, Haemophilus influenzae type b (Hib) can spread through the bloodstream (causing bacteremia) and infect the joints, bones, lungs, skin of the face and neck, eyes, urinary tract, and other organs.
The bacteria may cause two severe, often fatal infections:

Meningitis
Epiglottitis (infection of the flap of tissue over the voice box)

Some strains cause infection of the middle ear in children, the sinuses in children and adults, and the lungs in adults, especially those with chronic obstructive pulmonary disease (COPD) or AIDS.
Symptoms vary depending on the part of the body affected.