The bacterium Haemophilus influenzae was considered the pathogen of the typical influenza flu for a long time until orthomyxoviruses were identified as the actual cause. The bacterium is also known as the Pfeiffer bacterium, named after its discoverer Richard Pfeiffer. Different strains of the gram-negative, rod-shaped bacterium exist, with Haemophilus influenzae type b leading to most outbreaks. These various types can be distinguished by their capsule form: there are both encapsulated as well as unencapsulated (less virulent) strains of the bacterium. A vaccination against Haemophilus influenzae type b (Hib) exists; it is usually administered in Germany as part of basic immunization during infancy. The bacterium occurs exclusively in humans, primarily found in the mucous membranes. It needs blood to multiply (haemophilic).
Haemophilus influenzae is transmitted by sneezing or coughing through a droplet infection and then accumulates in the mouth and throat. It can also be transmitted through direct contact with infected material. The incubation period usually is only one or two days. Whether an outbreak of the disease occurs depends above all on the health of the immune system. This is why small children and immunocompromised adults are particularly susceptible. Although many people who are infected with the germ do not develop the disease, they can still infect others.
Typical illnesses caused by the pathogen are pneumonia, sinusitis or bronchitis. Particularly in unvaccinated infants, the bacterium can also trigger meningitis, which manifests itself through symptoms such as vomiting, high fever, cramps and a clouding of consciousness. Severe consequential damages (such as speech impairment, hearing loss or mental retardation) are possible. In addition, inflammation of the epiglottitis may occur within a few hours. The mortality rate is especially high for patients with meningitis, with up to 80 percent of patients dying if untreated. Even with treatment, the mortality rate is between 5-10 percent Infections with Hib-bacterium are more likely to cause serious infections.
Basic hygiene measures must be maintained. Particularly important here is hand disinfection and the disinfection of surfaces close to patients and hand-contact surfaces. In Germany, reporting of the detection of Haemophilus influenzae is mandatory according to the Infection Protection Act (IfSG).
About 12 days
The required spectrum of activity against Haemophilus influenzae is: bactericidal.