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Mycoplasma pneumoniae infection

Mycoplasma pneumoniae infection

17 May 2017

Causative agent

It is caused by the bacterium Mycoplasma pneumoniae. Mycoplasma pneumoniae infection can occur at any time of the year. Epidemics may occur every 3 to 4 years in the general population.

Clinical features

Mycoplasma pneumoniae most commonly causes acute upper and lower respiratory illness and the disease usually has a prolonged, gradual onset. The majority of patients present with upper respiratory tract symptoms, which may include fever, cough, sore throat, malaise and headache. Only 5 – 10% of infected patients develop atypical pneumonia. It is recognised as one of the most common causes of community-acquired pneumonia in otherwise healthy patients younger than 40 years, with the highest rate in individuals aged 5 – 20 years. Although Mycoplasma pneumoniae infection usually causes mild illness, severe complications such as severe pneumonia, encephalitis, renal impairment, and haemolytic anaemia may occur.

Mode of transmission

The disease is mainly transmitted from person-to-person by droplets. It may also be spread by direct contact with the nose and throat discharges of infected persons; or indirectly through contaminated articles freshly soiled by secretions of the infected person. Outbreaks usually occur in crowded institutional settings such as schools and residential homes.

Incubation period

The incubation period is commonly 3 weeks with a range of 1 – 4 weeks.


Antibiotics are very effective in treating Mycoplasma pneumoniae infection.


Vaccine is not available at the moment. As a general measure to prevent respiratory diseases, the members of public are advised to:

  • Build up good body immunity by having a proper diet, regular exercise and adequate rest, reducing stress and avoiding smoking.
  • Observe personal hygiene
    • Wash hands frequently with liquid soap and water, especially before touching the mouth, nose or eyes, or after touching public installations such as handrails or door knobs.
    • Cover nose and mouth with tissue paper when coughing or sneezing, and wash hands thoroughly afterwards. Dispose of soiled tissue paper in a lidded rubbish bin.
    • Put on a surgical mask when having respiratory symptoms. Refrain from work or school and seek medical advice promptly. 
  • Observe environmental hygiene
    • Maintain good ventilation of indoor areas.
    • Frequently clean and disinfect touched surface such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 - 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
    • Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, vomitus or excreta, and then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing 1 part of 5.25% bleach with 49 parts of water), leave for 15 - 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.