Ottawa – The majority of M. pneumoniae infections in adults are asymptomatic, but M. pneumoniae is the cause of many upper respiratory tract infections (up to 50% of cases). Symptoms develop over several days and persist for weeks to months, with common symptoms including sore throat, hoarseness, fever, cough (may be purulent), headaches, coryza, earache, myalgias, chills, and general malaise. There may also be dyspnea in the more severe cases and, in some cases, the cough may take on a pertussis-like character.
Some children may develop inflammation of the throat, cervical adenopathy, conjunctivitis, and myringitis. Progression to pneumonia is rare for children under five years of age, but common for those between 5 and 15 years old. M. pneumoniae is responsible for up to 40% cases of community-acquired pneumonia in children over 5, including primary atypical pneumonia and tracheobronchitis. Infections can be severe in the elderly or immunocompromised.
First aid/treatment
Macrolides are the first-line treatment for M. pneumoniae infection, specifically erythromycin (25-50 mg/kg/day for 14 days), clarithromycin (10-15 mg/kg/day for 10 days), and azithromycin (10 mg/kg/day for 3 days). For suspected macrolide-resistant infections, tetracyclines are recommended, such as doxycycline (4 mg/kg/day for 7-14 days). However, tetracyclines are contraindicated in young children. Fluoroquinolones are another alternative, but are contraindicated in children as well.
Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the CBH.
Immunization
No vaccine is currently available in Canada; however, various vaccines have been developed without much effectiveness for protecting against infection. Note: More information on the medical surveillance program can be found in the CBH, and by consulting the Canadian Immunization Guide.