**6. Conclusion**

Asthma is a heterogeneous disease that presents with similar clinical manifestations, is characterized by airway inflammation, and is likely to have different mechanisms of pathogenesis. Research suggests that multiple genetic and environmental factors, including respiratory pathogens and airway microbiome, interact to influence clinical manifestation, bronchial hyperresponsiveness, and the presence of atopy.

In addition to the role of viral infections in early life, many clinical and animal studies support the role of Chlamydia related respiratory infections in the development of asthma. Furthermore, *Chlamydia pneumonia* has been linked to severe and steroid-resistant asthma.
