Mycoplasma pneumoniae

Epidemiology

• humans are the only known reservoir
• spread of infection is person to person
• infections occur in endemic & epidemic forms
• epidemics are more common in summer & autumn
• more common in children & young adults
• 20% of all community-acquired pneumonia
• outbreak affecting 83 students at a Georgia University in 2012
• outbreak in long-term care facility in Nebraska 2014
• common infection in closed populations (residential facilities, boarding schools, military barracks ...)

Clinical manifestations

• incubation period is 2-3 weeks
• fever (85%)
• coryza
• pharyngitis (50%)
  • mucositis (image)
• bullous myringitis (20%)
• pulmonary manifestations
  • tracheobronchitis
  • pneumonia occurs in 3-10% of infected patients
  • interstitial pneumonia
  • bronchiolitis
  • cough (> 90%)
• hemolytic anemia
• erythema multiforme
• hepatitis
• Guillain-Barre syndrome

Laboratory

• Mycoplasma pneumoniae serology
  • complement fixation serology
    • 4 fold increase in titer in 50-80% of patients
• Mycoplasma pneumoniae DNA, Mycoplasma pneumoniae rRNA
• Mycoplasma pneumoniae culture
  • respiratory tract secretions
  • middle ear
  • cerebrospinal fluid (CSF)
• cold agglutinins
  • > 1:64 in 50% of patients
  • appear during 2nd to 3rd week after onset of symptoms
  • titer decreases to insignificant levels by 4-6 weeks
• abnormal liver function tests
• platelet count: thrombocytopenia
• see ARUP consult

Radiology

• chest X-ray
  • unilateral bronchopneumonia
  • lower lobe involvement (65%)
  • pleural effusion (5%)

Management

(antimicrobial therapy)

• macrolide
  • erythromycin
  • clarithromycin
  • azithromycin
• tetracycline or doxycycline
• fluoroquinolone
• resistance to beta-lactam antibiotics

More general terms

• Mycoplasma

Additional terms

• Mycoplasma DNA