Pathogens

Mycoplasma pneumoniae – Infection, Transmission & Diseases

Mycoplasma pneumoniae

Mycoplasma pneumoniae is one of the bacteria . The germ triggers, among other things, atypical pneumonia .

What is Mycoplasma pneumoniae?

The bacterium Mycoplasma pneumoniae belongs to the Mycoplasmataceae family . It causes various diseases, the most important of which is atypical inflammation of the lungs (pneumonia). A middle ear infection , an inflammation of the larynx , tracheobronchitis or meningitis can also be caused by the pathogen.

For a long time, doctors and scientists studying atypical pneumonia did not realize that Mycoplasma pneumoniae was a bacterium. The mycoplasma did not reach the size that was required for visualization with the microscopes of the time. Bacterial filters also had no effect on the germs . For this reason, Mycoplasma pneumoniae was given the name “Eaton’s Agent” at the time.

Occurrence, Distribution & Properties

Mycoplasma pneumoniae is unique to humans and can be found all over the world. The bacterium is transmitted by droplet infection . Therefore, the germ spreads particularly in places where there is active contact with sick people. These can be schools, kindergartens, children’s homes, military facilities or shared apartments. Children between the ages of 5 and 15 are particularly affected by an infestation with Mycoplasma pneumoniae.

With an average size of 0.1 to 0.6 µm, Mycoplasma pneumoniae is one of the smaller bacteria. The germ is equipped with both DNA and RNA. Although mycoplasmas are generally classified as flexible, their osmotic resistance is poor. Because they lack a cell wall, they cannot be identified by Gram staining.

Likewise, treatments with beta-lactam antibiotics are not crowned with success. These develop their effect only on bacteria that have a cell wall with a murein layer. The enzyme lysozyme, which occurs in the endosome, is also considered ineffective. Normally, the lysozyme attacks the cell wall of the bacteria, leading to their destruction.

Mycoplasma pneumoniae has an altered metabolism, which is why it is unable to synthesize cholesterol. The bacteria therefore need cholesterol from the host cell for their growth . Furthermore, the pathogen is equipped with special surface molecules. Although these are not pili, they can function as cytoadhesins to attach to the respiratory epithelium. There are pathogenicity factors such as special super antigens. These are B and T cell mitogens from which cell division is induced. In addition, oxygen radicals are formed, which cause epithelial damage.

Due to their flexible outer shape, the mycoplasma are able to penetrate filters that bacteria usually cannot. In a laboratory there is the possibility of cultivating Mycoplasma pneumoniae. After about two to eight days, the germ creates a so-called fried egg colony.

Mycoplasma pneumoniae is considered highly contagious. Inside the human body, the bacterium acts like a parasite and attaches itself to the epithelial cells of the lungs , known as cilia. Through certain protein structures, the mycoplasma attaches itself to the mobile cilia and slides down their roots. At this point, the multiplication of the pathogen begins.

H2O2 (hydrogen peroxide) is produced by Mycoplasma pneumoniae. As the hydrogen peroxide penetrates into the cells of the ciliated epithelium, it can damage them. For this reason, mucus and other substances are only insufficiently removed from the lungs. In addition, the mycoplasma make the work of the human body’s defense system harder and can also protect itself from it. In this way, a longer survival of the germs is possible. Furthermore, Mycoplasma pneumoniae procures missing nutrients from the cilia.

Diseases & Ailments

Mycoplasma pneumoniae is not found in healthy people, but it can be easily transmitted, causing various diseases. Children in particular often suffer from atypical or interstitial pneumonia. In most cases, however, there is only a slight sore throat . A diagnosis is therefore usually not made.

After an infection with Mycoplasma pneumoniae, it takes about 10 to 20 days for the first symptoms to appear. These primarily include a nagging cough with little sputum , fever and headache , with the symptoms progressing only slowly.

As the disease progresses, there is a risk of atypical pneumonia developing. In contrast to conventional pneumonia, the doctor cannot hear any sounds when listening to and patting the chest, which is otherwise heard with pneumonia. In some cases, however, there are only slight symptoms or even no symptoms at all.

In addition to atypical pneumonia, Mycoplasma pneumoniae causes other diseases. These are haemolytic anemia , tracheobronchitis, pharyngitis ( inflammation of the throat ), muscle pain and maculopapillary erythema .

Severe neurological diseases can also occur. Doctors also suspect that there is a connection between a Mycoplasma pneumoniae infection and bronchial asthma .

In order to detect Mycoplasma pneumoniae in the patient’s body, material is obtained from the sputum or tracheal secretion. In addition, antibodies can be detected by ELISA or a complement fixation reaction (CBR).

The treatment of diseases caused by Mycoplasma pneumoniae is usually through the administration of tetracyclines such as doxycycline . Children are mostly given macrolides such as erythromycin . On the other hand, cephalosporins or penicillin are not suitable for treatment because the mycoplasma are not equipped with a cell wall.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.