Mycoplasma pneumoniae is the smallest free-living organism that causes pneumonia in humans. It lacks a cell wall and resides extracellularly in the respiratory tract. Common symptoms include fever, cough, headache, and sore throat. Examination may reveal rhonchi or rales in the lungs. Diagnosis is confirmed through PCR testing of respiratory samples, though this is not used in clinical practice. Treatment involves antibiotics like erythromycin, clarithromycin, or azithromycin for 7-10 days.

1. MYCOPLASMA
PNEUMONIA

2. Introduction
• Mycoplasma species are the smallest free-living
organisms. (150-250 nm)
• Pleomorphic organism
• unlike bacteria, lacks a cell wall,
• unlike viruses, does not need a host cell for replication.
• Prokaryotes - lack a cell wall - Lack of a reaction to Gram
stain and lack of susceptibility to many antimicrobial
agents
• Usually associated with mucosal surfaces, residing
extracellularly in the respiratory and urogenital tracts.
• Mycoplasma pneumoniae, Mycoplasma hominis,
Mycoplasma genitalium, and Ureaplasma species.

4. Pathophysiology
• The Mycoplasma organism produces a protein that allows
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attachment to a receptor on the respiratory epithelium.
Gliding motility and specialized filamentous tips - burrow
between cilia within the respiratory epithelium
Inhibition of ciliary movement
Sloughing of the respiratory epithelial cells
M.pneumoniae Pathogenesis in respiratory tract is due to
• Selective affinity for respiratory epithelial cells
• Ability to produce hydrogen peroxide

5. Epidemiology
• One of the common causes of acquired pneumonias in
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healthy patients. < 40 years.
Common in all age groups
Rare in <5 yeas old children
Highest rates are seen in 5-20 year age group.
The incubation period is 1-3 weeks.
They are spread by large particles by aerosol to close
contacts.

6. Presentation
• Disease of gradual and insidious onset of several days to
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weeks.
Fever
Malaise
Persistent, slowly worsening dry cough
Headache
Chills, not rigors
Scratchy sore throat
Sore chest and tracheal tenderness (result of the
protracted cough)

7. Presentation
• Less common symptoms include:
• Ear pain
• Muscle aches
• Pleuritic chest pain (rare)
• Extrapulmonary symptoms are thought to be autoimmune
induced
• rashes
• Stevens Johnson Syndrome
• meningoencephalitis
• arthritis, gastrointestinal symptoms

8. Examination
• A nontoxic general appearance
• Normal lung findings with early infection but rhonchi,
rales, and/or wheezes several days later
• Erythematous tympanic membranes - an uncommon but
unique sign

9. Investigations
• Laboratory tests are generally of limited benefit
• Elevated ESR
• Normal or elevated WBC
• Sputum Gram stains and cultures not helpful
• M pneumoniae lacks a cell wall and cannot be stained
• difficult to culture and requires 7-21 days to grow
• Polymerase chain reaction (PCR) - accurately diagnose
atypical pneumonia
• used for epidemiologic studies
• not used in clinical practice

10. Radiographic findings
• Multifocal, bilateral diffuse infiltrates most frequent
• occasionally have lobar pneumonia picture.
• Pleural effusions are not rare
• The x-ray often looks worse than the clinical picture.

11. Treatment
• Suggested to teat for 7-10 days.
• Empiric antimicrobial therapy must be comprehensive and
should cover all likely pathogens in the context of the clinical
setting.
• Antimicrobials against M pneumoniae are bacteriostatic-not
bactericidal
• Erythromycin - Will also be effective against other community
acquired infections such as pneumococcal pneumonia.
• Clarithromycin and Azithromycin
• Tetracylcines in patients > 10 years old (Doxycycline)
• Levofloxacin

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