Mycoplasmas are the smallest free-living microorganisms known. They may exist as part of the normal flora found in the throat, upper respiratory tract, and genitourinary tract. Mycoplasmas are unlike other types of bacteria in many ways and can be difficult to culture and identify.
When they were first discovered, mycoplasmas organisms were believed to be viruses because they pass through filters that retain bacteria. However, unlike viruses, they are able to grow in cell-free media and contain both RNA and DNA. Mycoplasma species have also been mistakenly believed to be L-forms of bacteria, which also lack cell walls. Unlike mycoplasma organisms, L-form bacteria do not have sterols in the cell membranes, and they can revert to their walled parental forms.
The most common specie, Mycoplasma pneumonia, typically causes respiratory infections like pneumonia, bronchitis, pharyngitis, and asthma. But it’s a stealth pathogen that can also cause non-respiratory diseases affecting the nervous system, blood, joints, skin, heart, liver, and pancreas. Estimates of Mycoplasma pneumonia cases each year in the United States are typically as high as two million. The disease tends to be cyclical both within a given year and across a decade.
Mycoplasma pneumoniae likes to live on the surface cells (mucosa) of the respiratory tract and can cause inflammation of most structures there. Bronchitis is most common. But it can also cause pneumonia/pneumonitis, laryngitis, and myringitis (inflammation of the eardrum).
Mycoplasma is usually the cause of “walking pneumonia.” As it’s often abbreviated, causes pneumonia – flulike symptoms such as fever, nonproductive cough, generalized aches and pains, and nasal congestion. Typical pneumonia, on the other hand, usually involves a productive cough and chest pain close to the site of the pneumonia.