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.
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synoviae is often perplexed due to cross reactions and nonspecific reactants in serum of chicks, thus true picture of the flock status is revealed by ELISA which is used as back up test for screening of flock for mycoplasma infection.
synoviae is often perplexed due to cross reactions and nonspecific reactants in serum of chicks, but it is also true that it is necessary to know the mycoplasma infection status of chicken flock as it helps to develop the strategies to combat infection (Haghighi-khoshkhoo et al.
Only 1 isolate was identified in the bronchoalveolar lavage sample from a ferret for which postmortem examination confirmed lesions consistent with a mycoplasma infection.
Table 1 Mycoplasma infections in cancer patients Number Positive for Total Positive Patient Percent Cancer Type Mycoplasma Number Positive Breast Cancer 25 63 39.
To show that mycoplasma infection could worsen HIV disease, Lo and his colleagues infected separate cultures of human white blood cells -- called CD4 lymphocytes -- with HIV alone, with M.
The source of Mycoplasma infection in markhors is unknown, but domestic goats, which have contact with markhors, particularly in the summer, might have been responsible for the emergence of M.
However, PCR assays may overestimate the incidence of Mycoplasma infections.
Number of reported hemotrophic mycoplasma infections, China, 1994-2007 * Species Year Human Cow Swine Sheep Fox 1994 200 NR NR NR NR 1995 331 132 NR 231 NR 1996 1,229 259 147 NR NR 1997 2,262 69 1,282 126 NR 1998 740 64 127 115 NR 1999 3,861 1,460 397 2,493 954 2000 1,971 2,920 140 NR 371 2001 329 329 7,775 NR 16,697 2002 126 NR 17,068 NR 17,068 2003 880 84 600,033 1,877 31,208 2004 4 625 15,604 206 NR 2005 451 119 27,268 2,916 20 2006 4 75 15,916 536 465 2007 452 3 1,686 53 60 * NR, no record.
A hemotrophic mycoplasma infection was reported in patients with systemic lupus erythematosus (SLE) (6).
Increased susceptibility to Mycoplasma infection in patients with hypogammaglobulinaemia.
The most common infection of the endometrium in the study group was mycoplasma infection (33.
Replication of vaccinal virus in chicken body post-vaccination formaldehyde poisoning during spray accumulation of ammonia gas due to poor ventilation and flow of dust particles in air due to very dry litter cause potential damage to tracheal epithelium of the chickens during inhalation which in turn support the multiplication of contaminating Mycoplasma infection (Anderson et al.