Mycoplasmas are small, cell-wall-free bacteria belonging to the family of Mycoplasmataceae. Among other things, they can cause respiratory problems in humans.

What are mycoplasma?

Mycoplasmas are bacteria of the genus Mollicutes. They are the smallest bacteria that can multiply independently. They are between 0.3 and 2 microns in size. Normally bacteria have a cell wall or a murein layer. The mycoplasma, however, lacks this outer shell. They are therefore also referred to as cell-wall-free bacteria. The genome, ie the totality of all genes, is also rather small in mycoplasmas with 600 kbp. As a result, the mycoplasmas can not perform many metabolic reactions that are self-evident in other bacterial species.

Mycoplasmas prefer aerobic lifeplaces. Under the influence of oxygen they can best gain energy. But they also belong to the facultative anaerobic bacteria, so even without oxygen cope a time.

The bacteria are pleomorphic. This means that they can adapt their shape according to their stage of development and environmental conditions. Normally they are in a vesicular form. Clinically important mycoplasmas include Mycoplasma pneumoniae, Mycoplasma genitalum, Ureaplasma urealyticum and Mycoplasma fermentans.

Occurrence, distribution & characteristics

The small genome restricts the mycoplasmas in their metabolic processes. They are therefore dependent on a parasitic lifestyle. In the human body, the small bacteria live as parasites on the surface of epithelial cells. Epithelial tissue coats the inner and outer surfaces of the body. Of the epithelial cells, the bacteria are forced to receive nucleotides, amino acids, fatty acids and cholesterol. These substances are essential growth factors for mycoplasma.

The pathogen Mycoplasma pneumoniae does not occur in healthy people. It is a highly contagious germ that is transmitted by droplet infection. Especially in community facilities such as kindergartens or schools it comes to epidemics. Children are particularly at risk of becoming infected with the virus. Your immune system is not that strong yet. When the germ enters the body, it can attach itself to the ciliary epithelium of the respiratory tract using special organelles.

The pathogen Mycoplasma hominis, however, also occurs in healthy people. He lives in the gastrointestinal tract. On the other hand, he lives there only as a commensal. Commensales are living things that feed on the food residues in a host organism. In contrast to the parasite, they do not harm the host. In principle, Mycoplasma hominis does not cause any pathogenic reactions. However, if the pathogen enters the genitourinary tract, it can cause urinary tract infections. The same applies to the bacterium Mycoplasma genitalium. It also inhabits the genital and respiratory tract as a commensal.

Not much is known about the habitats of Mycoplasma fermentans. However, it is found conspicuously in HIV patients.

Diseases & complaints

The pathogen Mycoplasma pneumoniae is highly contagious. As a rule, an infection with the bacterium leads to a slight tracheobronchitis, ie inflammation of the trachea and the bronchi. A typical symptom of tracheobronchitis is coughing. Obstructive symptoms, such as stridor, can also occur. These symptoms are caused by the inflammation of the bronchial mucosa and the resulting swelling and increased mucus production. The cough is initially dry. The more mucus is produced, the more productive the cough becomes. The ejection is then colored yellow-greenish. He can also be thinner. Often an infection with Mycoplasma pneumoniae manifests itself only by a slight sore throat, so that often no diagnosis is made at all.

In younger children, atypical, interstitial pneumonia may develop. Interstitial pneumonia does not affect the alveoli but the interstitium. Acute interstitial pneumonia is characterized by coughing and severe fatigue.

The pathogen can not only settle in the bronchi, but also manifest extrapulmonary. This can, for example, come to a middle ear infection. Also, pancreatitis, arthritis and diseases of the central nervous system such as meningitis or myelitis can be caused by Mycoplasma pneumoniae. Likewise, haemolytic anemia may develop as part of the infection. Also cardiac arrhythmias, rash and liver inflammation are possible.

The bacterium Ureaplasma urealyticum can cause various inflammations in the urogenital tract. So the bacterium is the causative agent of nonspecific urethritis. This is also called non-gonococcal urethritis. It is accompanied by pain in urination and discharge. Also, bladder and prostate infections can be caused by the bacterium. Typical symptoms of bladder infection are pain and burning sensation on urination, urinary frequency with low urinary excretion, bladder cramps, urinary blood, abdominal pain and, in severe cases, fever.

The inflammation of the prostate (prostatitis) is also expressed by pain when urinating. As with cystitis sufferers suffer from frequent urinary urgency. There are also urinary drainage disorders, pain in the penis, testicles and peritoneum, and pain during and after ejaculation.

The bacterium Ureaplasma urealyticum may also cause neonatal sepsis. It is a systemic infection of the newborn. Preterm babies and children with low birth weight, in particular, can become infected with the bacteria at birth.

Due to the lack of cell wall, antibiotics that attach to the cell wall of bacteria can not work on mycoplasmas. For the treatment of mycoplasma infections therefore macrolides or quinolones must be used. Even if the side effects of quinolones and macrolides are often more serious than the side effects of antibiotic drugs.

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