People with severe asthma are more likely to have antibodies against the disease-causing bacteria Chlamydia pneumoniae than the general population and in some cases antibiotic treatment can greatly improve symptoms according to new research. Moreover, patients who were treated on the basis of asthma severity with antibiotics had significant improvements in asthma symptoms and some even experienced a complete abolition of these symptoms.

Source: The role of bacteria in asthma and the potential for antibiotic treatment