"M.pneumoniae is the leading cause of pneumonia in school- age children and young adults. Infection with this bacterium is usually mild and most commonly results in acute bronchitis and upper respiratory infections, it leads to pneumonia in approximately 10% of cases. The disease is usually self-limiting, and treatmentwith macrolides. However, resistance to macrolides, the firstline antibiotic used to treat M. pneumoniae has emerged in both paediatric and adult populations in Asia, Europe and the United States since 2000. Internationally, resistance rates vary from 10% (North America) to 90% (China)."