[Etology and treatment of community acquired pneumonia in children].

In children under 5 years, most lower respiratory tract infections are caused by viruses and do not require antibiotics. This is true for almost all episodes of bronchitis and bronchiolitis but also for the majority of pneumonias. Atypical pneumonias due to Mycoplasma pneumoniae or Chlamydia pneumoniae predominate in older children while Streptococcus pneumoniae remains by far the most common cause of bacterial pneumonia. Diagnosis of pneumonia itself can be difficult and relies on a combination of clinical judgement and radiological and laboratory investigations. In real-life situations, etiologic agents are rarely identified, an issue further complicated by the possibility of mixed infections particularly in hospitalised children. Since viruses are often the sole cause of pneumonia in childhood, it is appropriate not to treat every child with antibiotics. However, when a bacterial origin can not be excluded, antibiotics efficient on Streptococcus pneumoniae are to be prescribed. Amoxicillin is the first choice empirical antibiotic treatment, having a higher efficacy on poorly sensitive pneumococcus than cephalosporins. Macrolides are indicated for the treatment of atypical pneumonia. Current immunisation strategies have decreased the number of bacterial pneumonias. However, there is some evidence that among hospitalised children the rate of complicated pneumonias is increasing with an emerging role of Streptococcus pneumoniae serotype 1, which is not covered in the 7-valent vaccine.