What Is Haemophilus Influenzae Bacteria?

Haemophilus influenzae (H. flu) is a species of bacteria associated with infections of the eyes, ears, throat, lungs, and, in severe cases, the brain and epiglottis. There are different types, or serogroups, of H. flu, with serogroup b being the most serious one.

Appearance

• Under the microscope, H. flu looks like tiny rods or almost like train boxcars. When stained with Gram stain, the bacteria appear pink (Gram negative).

Infections

• H. flu bacteria cause different infections, particularly in children, whose immune systems are not fully developed. Despite this, it is normally found in the nose cavity of about 75 percent of children.

Transmission

• H. flu bacteria are transferred through contaminated droplets of respiratory secretions from person to person. Simple droplet precautions, such as a mask, gown, and gloves, may be enough to prevent infection, along with regular hand washing.

Hib

• Haemophilus influenza type b (Hib) is the most dangerous type of H. flu, causing meningitis in non-immunized children. Because of the introduction of a vaccine in 1988, the annual number of Hib infections dropped from about 20,000 to just under 200.

Treatment

• H. flu bacterial infections respond well to antibiotics. Which antibiotics are given and for how long depends on the patient and the site of the infection.

Fun Fact

• H. flu was found in many patients who died from the flu when the virus was not yet known to exist, hence the name "H. flu". Haemophilus means "blood loving" in Latin, and it was chosen because the bacteria grows best in petri dish cultures with blood.