Summary
Mycoplasma pneumoniae is a pleomorphic free-living organism that belongs to the Mycoplasmataceae family [1]. It is also sometimes referred to as the Eaton agent, named so after the name of the researcher who initially isolated the organism [2].
Mycoplasma pneumoniae is a pleomorphic free-living organism that belongs to the Mycoplasmataceae family [1]. It is also sometimes referred to as the Eaton agent, named so after the name of the researcher who initially isolated the organism [2].
Virulence and microbiologic features:
- The peptidoglycan-containing cell wall is absent in mycoplasma pneumoniae, rendering it resistant to antibiotics that target cell wall synthesis, such as penicillin and cephalosporins [1].
- It has a sterols-containing cell membrane [1].
- The organism is motile and depends on the presence of cholesterol for its membrane synthesis [3].
- It exhibits strict aerobic respiration [4] and can thrive and reproduce outside the host cell [3].
- A clinically important virulence factor of mycoplasma pneumoniae is the P1 protein, which facilitates bacterial attachment with target cells of the respiratory tract [3].
- It does not produce toxins [3].
- Recruitment of inflammatory cells and cytokine release in response to the bacterium contribute to bacterial elimination and disease manifestation [4].
Transmission:
- Transmission is through respiratory route [1]
Disease and complications:
- Tracheobronchitis [5]
- Atypical pneumonia or walking pneumonia: The patient can present with a nonproductive cough and fever. Imaging studies such as X-rays will confirm streaky infiltrate and imaging findings appear worse than observed physical signs and reported symptoms. [1,5]
Two chest x-rays in the case by Centers for Disease Control and Prevention is marked with CC0 1.0.
- Some other conditions that can develop in some patients infected with mycoplasma pneumoniae include Steven-Johnson syndrome and erythema multiforme [1].
Diagnostic Testing:
- Cold agglutinins: These are monoclonal IgM antibodies aginst I antigen of RBCs. These antibodies cause RBC agglutination at lower temperature, i.e., at 4°C. [1]
File:Red blood cell agglutination due to cold agglutinin.jpg by Spicy is licensed under CC BY-SA 4.0.
- Culture of the sputum specimen will show colonies with a mulberry appearance. [1]
- Complement fixation test can also detect rising antibody titers [1].
- Rapid detection is possible through mycoplasma DNA probe and PCR [1].
References:
- CMMRS edition 6, 2016-17 (page no: 156)
- Medical Microbiology by Patrick R. Murray Ph.D., Ken Rosenthal Ph.D., Michael A. Pfaller MD, 8th edition (page no: 334)
- CMMRS edition 6, 2016-17 (page no: 158)
- Medical Microbiology by Patrick R. Murray Ph.D., Ken Rosenthal Ph.D., Michael A. Pfaller MD, 8th edition (page no: 335
- CMMRS edition 6, 2016-17 (page no: 159)