Mycoplasma pneumoniae, Molecular Detection, PCR
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mycoplasma pneumoniae is a small bacterium transmitted via organism-containing droplets. It is a cause of upper respiratory infection, pharyngitis, and tracheobronchitis, particularly in children, and has been associated with approximately 20% of cases of community acquired pneumonia.(1) Central nervous system and cardiac manifestations are probably the most frequent extrapulmonary complications of infections due to Mycoplasma pneumoniae. The disease is usually self-limited although severe disease has been reported in immunocompromised patients.(2)
Identification of Mycoplasma pneumoniae by culture-based methods is time consuming and insensitive. Serology based assays for Mycoplasma pneumoniae have several drawbacks. The development of IgM antibodies takes approximately 1 week and the IgM response in adults may be variable or it may be decreased in immunosuppressed individuals.(3,4) Confirmation of the disease may be dependent on the observation of a 4-fold rise in IgG antibody titers between acute and convalescent specimens, several weeks following the initial onset of illness, providing clinical utility only for retrospective testing.(4) Real-time PCR offers a rapid and sensitive option for detection of Mycoplasma pneumoniae DNA from clinical specimens.
Diagnosis of infections due to Mycoplasma pneumoniae
A positive result indicates the presence of Mycoplasma pneumoniae.
A negative result does not rule out the presence of Mycoplasma pneumoniae and may be due to the presence of inhibitors within the specimen matrix, or the presence of organisms at numbers below the limits of detection of the assay.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This assay should only be used for testing of respiratory tract specimens (throat swabs, nasopharyngeal swabs, tracheal secretions, sputum, and bronchoalveolar lavage fluid) and pleural/chest fluid, pericardial fluid, and cerebrospinal fluid.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
3. Daxboeck F, Krause R, Wenisch C: Laboratory diagnosis of Mycoplasma pneumoniae infection. Clin Microbiol Infect 2003;9:263-273