What is a superinfection?
The term “superinfection” is not clearly defined medically. Usually, when doctors speak of a superinfection, they mean a bacterial infection based on a previous viral infection. However, a superinfection is also often spoken of when a chronic disease favors an infection.
A common example of this is an infection of the skin with bacteria in the case of pre-existing neurodermatitis. This is often referred to as a secondary infection. The terms are not sharply separated from each other. In virology, a superinfection usually refers to an infection of a cell with a virus that leads to a secondary infection with another virus or another strain of the same pathogen.
Causes of a superinfection
A superinfection can have various causes. A common example of a superinfection is a bacterial infection of the skin in case of pre-existing neurodermatitis. The cause is the disruption of the skin barrier by the chronic inflammatory skin disease neurodermatitis, which makes it easier for bacteria to spread.
Another cause of superinfection is diabetes mellitus, in which circulatory disorders can lead to chronic wounds and dead tissue – in short: necrosis – on the feet. There, too, bacteria can easily lead to superinfections. In the lungs, a viral infection is often followed by a bacterial superinfection, which can even lead to pneumonia.
A classic example from virology is infection with the hepatitis D virus, which is only possible after a previous hepatitis B infection. What superinfections have in common is that they require a previous infection or weakening of the immune system through an inflammation in order to spread. Superinfections can be caused by various pathogens.
Bacterial super-infections develop on the skin, preferably through so-called staphylococci or streptococci. An infection caused by staphylococci is often also called staphyloderma. Streptococcal infections of the skin, as they can occur in neurodermatitis, for example, are often referred to as impetiginization. However, other bacteria can also be involved in the development of superinfections, such as Pseudomonas aeruginosa in wound infections or pneumococci and Haemophilus influenza in the lungs.
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