Mycoplasma pneumonia

Affects children (over age 3 years) and young adults
1. Causes up to 40% of Community Acquired Pneumonia cases (esp. children age >5 years, young adults)
2. May also be seen in the elderly

Mycoplasma pneumoniae
1. Mycoplasma are tiny, pleumorphic (may be cocci or rods) and lack a cell wall (gram neutral)
2. Adhesin Virulence Protein P1
  1. Allows for Bacterial attachment to respiratory epithelium
Results in respiratory infections
1. Atypical Pneumonia (3-10% of infected patients)
  1. Interstitial infection of lung parenchyma
  2. Incubation Period: 2-3 weeks after infection
2. Acute Tracheobronchitis
3. Upper Respiratory Infection

Slow, gradual onset of prodromal symptoms
1. Malaise
2. Headache
3. Fever
  1. Usually present longer than 3 days at presentation
Cough
1. Constant, harsh, dry, hacking non-productive cough
Upper respiratory symptoms (50%)
1. Pharyngitis
2. Ear Pain
Accompanying symptoms
1. Rash
2. Arthralgias

Minimal signs
1. Mild Pneumonia more consistent with Viral Pneumonia
Chest auscultation
1. Scattered rhonchi
2. Localized rales
Serous Otitis Media
Wheezing may be present
1. Usually absent in other Bacterial Pneumonia
2. Wheezing otherwise more common with Viral Pneumonia

Complete Blood Count
1. WBC Count mildly elevated (10,000 to 15,000)
Mycoplasma DNA PCR
1. Modern approach to organism identification
Cold Agglutinins
1. Based on monoclonal IgM development to RBC i Antigen
  1. RBCs agglutinate (clump) at 4C when i Antigen IgM is present (in a non-clotting tube)
  2. RBCs will unclump on rewarming
2. Nonspecific and Not sensitive (False Negative in 33% of cases)
  1. I Antigen IgM develops over the first 2 weeks of infection, peaks week 3, declines over months
Mycoplasma complement fixation titers
1. Mycoplasma Glycolipid Antigens are combined with patient blood to obtain Antibody titers
2. Obtain acute and convalescent titers
Sputum Culture
1. Grown on media rich in Cholesterol and Nucleic Acids
2. Form dome-shaped (fried-egg shaped) colonies after 2-3 weeks of growth

See Community Acquired Pneumonia Management
Dosing is listed for adults (see specific agents for pediatric dosing)
Doxycycline
1. Avoid in age <8 years or pregnancy
2. Dosing: 100 mg orally or IV twice daily for 7-10 days
Alternatives: Macrolides (increasing resistance)
1. Azithromycin (Zithromax) 500 mg orally on day 1, then 250 mg orally on days 2-5 years
2. Erythromycin
3. Clarithromycin (Biaxin)
Alternatives: Fluoroquinolones
1. Levofloxacin 750 mg orally or IV for 5 days