Mycoplasma Infections


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Related to Mycoplasma Infections: Mycoplasma pneumoniae

Mycoplasma Infections

 

Definition

Mycoplasma are the smallest of the free-living organisms. (Unlike viruses, mycoplasma can reproduce outside of living cells.) Many species within the genus Mycoplasma thrive as parasites in human, bird, and animal hosts. Some species can cause disease in humans.

Description

Mycoplasma are found most often on the surfaces of mucous membranes. They can cause chronic inflammatory diseases of the respiratory system, urogenital tract, and joints. The most common human illnesses caused by mycoplasma are due to infection with M. pneumoniae, which is responsible for 10-20% of all pneumonias. This type of pneumonia is also called atypical pneumonia, walking pneumonia, or community-acquired pneumonia. Infection moves easily among people in close contact because it is spread primarily when infected droplets circulate in the air (that is, become aerosolized), usually due to coughing, spitting, or sneezing.

Causes and symptoms

Atypical pneumonias can affect otherwise healthy people who have close contact with one another. Pneumonia caused by M. pneumoniae may start out with symptoms of an upper respiratory infection, probably a sore throat progressing to a dry cough within a few days. Gradually, fever, fatigue, muscle aches, and a cough that produces thin sputum (spit or phlegm) will emerge. Nonrespiratory symptoms may occur too: abdominal pain, headache, and diarrhea; about 20% of patients may have ear pain.
Another mycoplasma species, M. hominis, is common in the mucous membranes of the genital area (including the cervix), and can cause infection in both males and females. Its presence does not always result in symptoms.

Diagnosis

Usually, mycoplasma pneumonia will be identified after other common diagnoses are set aside. For example, a type of antibiotic known as a beta-lactam might be prescribed for a respiratory infection producing fever and cough. If symptoms do not improve in 3-5 days, the organism causing the disease is not a typical one and not susceptible to these antibiotics. If a Gram's stain (a common test done on sputum) does not indicate a gram-positive pathogen, the doctor will suspect a gram-negative organism, such as mycoplasma. The actual underlying organism may not be identified (it is not in almost 50% of cases of atypical pneumonia). Although it is rare, a rash may appear along with pneumonia symptoms. This should trigger suspicion of mycoplasma pneumonia, even if laboratory tests are inconclusive.
Standard x rays may reveal a patchy material that has entered the tissue; this can be evident for months. Laboratory tests include cold agglutinins, complement fixation, culture, and enzyme immunoassay. The presence of infection with M. pneumoniae would be indicated by a fourfold rise in M. pneumoniae-specific antibody in serum, during the illness or convalescence. Highly sophisticated and specific polymerase chain reaction methods (PCR) have been developed for many respiratory pathogens, including M. pneumoniae. They are not readily available and are very expensive.

Key terms

Community-acquired — Refers to an infectious disease that is passed among individuals who have close contact with one another.

Treatment

A 2-3 week course of certain antibiotics (erythromycin, azithromycin, clarithromycin, dirithromycin, or doxycycline) is generally prescribed for atypical pneumonia. This disease is infectious for weeks, even after the patient starts antibiotics. A persistent cough may linger for 6 weeks.

Prognosis

Mycoplasma pneumonia may be involved in the onset of asthma in adults; other rare complications include meningoencephalitis, Guillain-Barré syndrome, mononeuritis multiplex, myocarditis, or pericarditis. This may increase the risk of acute arrhythmias leading to sudden cardiac death. However, with proper treatment and rest, recovery should be complete.

Prevention

At this time, there are no vaccines for mycoplasma infection. It is difficult to control its spread, especially in a group setting. The best measures are still the simplest ones. Avoid exposure to people with respiratory infections whenever possible. A person who has a respiratory infection should cover the face while coughing or sneezing.

Resources

Books

Cassell, Gail H., Gregory G. Gray, and K. B. Waites. "Mycoplasma Infections." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.
References in periodicals archive ?
The most common infection of the endometrium in the study group was mycoplasma infection (33.2%) and chlamydia infection (28.6%).
Table 1 Mycoplasma infections in cancer patients Number Positive for Total Positive Patient Percent Cancer Type Mycoplasma Number Positive Breast Cancer 25 63 39.7% Colon Cancer 32 58 55.1% Adenomarous polyp 10 49 20.9% Gastric Carcinoma 50 90 56.0% Oesophageal Cancer 27 53 50.9% Lung Cancer 31 59 52.6% Glioma 38 91 41.0%
Although the CF and Remel tests both indicated Mycoplasma infection on the six paired serum specimens tested, the Remel test is now preferred because of its improved specificity.
But Folks adds he won't be convinced completely of the link until epidemiological studies show that most AIDS patients also have mycoplasma infections.
Due to the lack of information about Mycoplasma infections among Egyptian patients, this study was done in order to characterize the different species of Mycoplasma among patients admitted to public and university hospitals in Cairo, Egypt.
Several serological tests such as complement fixation test (CFT), indirect haemagglutination test (IHA), enzyme- linked immune-sorbent assays (ELISA) and Latex agglutination test (LAT) are reported for the diagnosis of Mycoplasma infection (March et al., 2003).
Among the 10 healthy ferrets, no gross or histologic lesions suggestive of mycoplasma infection were identified.
Environmental and nutritional stressors may exacerbate the susceptibility of ruminants to Mycoplasma infections (2,15).
We conducted an epidemiologic investigation of hemotrophic mycoplasma infections in China by reviewing all reported cases and outbreaks for 1994-2007.
Disease associations with latent mycoplasma infections in immunocompromised and nonimmunocompromised patients are now emerging.
These findings should be considered especially for humans highly susceptible to Mycoplasma infections, including children and persons with congenital or acquired immunodeficiencies (2,3).