Pneumonia is an inflammation of the lungs usually caused by a bacteria or virus. Respiratory infection from bacteria-like Mycoplasmas causes atypically mild symptoms.

What Is Pneumonia?

Pneumonia occurs when the lungs' air sacs and small airways fill with liquid and cannot function properly. When gas exchange is impeded, the body cannot take in oxygen as it normally would. Oxygen is vital to the body’s cells, where it is needed for aerobic respiration; the breakdown of glucose to obtain energy for cellular work.

Causes of Pneumonia

Pneumonia can have many different causes: viral, bacterial, fungal or, in the case of aspiration pneumonia, may result from the inhalation of substances such as caustic chemicals, food or vomit.

Bacterial Pneumonia

All bacteria are prokaryotes (Pro = “before”, karyon = “nucleus”). Prokaryotes were the first type of cell to evolve, and still lack a membrane bound nucleus; their genetic material is naked within the cytoplasm.

Of different types of pneumonias, bacterial tends to be the most serious and, in adults, the most common. Bacterial pneumonia may follow influenza or even a common cold, particularly the elderly or immune compromised.

Mycoplasmas

Mycoplasmas are very simple unicellular organisms in the taxonomic phylum Firmicutes and are most likely descended from Gram-positive bacteria. They cannot perform many metabolic functions, and are considered the perfect model of the minimalist cell, believed to contain the absolute minimum cellular machinery necessary for survival. None are free-living. They are strictly parasites in a wide range of organisms, including humans.

Mycoplasmas can colonize the mucous membranes of the respiratory and urinary tracts, and therefore are commonly associated with pneumonia and urinary tract infections (UTIs). At least forty-six species of Mycoplasmas have been identified, but of these, only a few are human pathogens.

Primary Atypical Pneumonia

Organism: Mycoplasma pneumoniae

Symptoms

The early symptoms of pneumonia caused by M. pneumoniae--fever, malaise, headache and sore throat--are not typical signs of pneumonia, hence the name Primary Atypical Pneumonia. Symptoms can last for several weeks, but are rarely severe enough to result in hospitalization or death. Because the symptoms are mild, this disease is also known as ‘Walking Pneumonia’.

Transmission and Diagnosis

M. pneumoniae are spread through the nasal secretions of people in close contact. Primary Atypical pneumonia most commonly occurs in children between the ages of 5 and 15. It is difficult to diagnose, and not being a reportable disease, the actual incidence is unknown. Unlike pneumococcal pneumonia, Primary Atypical Pneumonia is not seasonal, and cases occur throughout the year.

Other Diseases Linked to Mycoplasma

In addition to causing pneumonia, Mycoplasmas have been linked with several chronic diseases, including chronic fatigue syndrome, fibromyalgia syndrome, gulf war syndrome, and rheumatoid arthritis.

This article contains a brief summary of some of Primary Atypical Pneumonia. It s not intended for use in self-diagnosis. If you are ill, see your health care provider.

Pneumonia Resources

For more information on pneumonia, see the Mayo Clinic: Infectious Diseases or Science Prof Online. For additional material on other types of pneumonia see the Suite101.com articles Gram Positive Bacterial Pneumonia, Gram Negative Bacterial Pneumonia and Endemic Fungal Pneumonia.

Sources

Bauman, R. (2005) Microbiology.

Park Talaro, K. (2008) Foundations in Microbiology.