Relationship of Asthma Severity With Haemophilus influenzae Type A Infection in Patients With Asthma Compared to Healthy People

Background: Asthma is a chronic respiratory disease characterized by bronchospasm, airway inflammation. The occurrence of microbial infections is related to the severity of asthma symptoms; thus, their development can be prevented by controlling microbial agents. This study aims to determine the relationship of asthma symptoms severity with Haemophilus influenzae type A infection in patient with asthma compared to healthy people. Methods: In this case-control study, sputum samples of 31 patients with asthma (16men and 15 women; mean age=58.58±14.13) and 31 healthy individuals (16 men and 15 women; mean age=52.03±14.72 years) who referred to a hospital were collected. DNA extraction was done using the kit (Cinnagen Co.). The prevalence of H. influenzae type A was investigated using the bexA gene primer by real-time PCR method. The collected data were analyzed in Excel and SPSS software, version 20. Results: 24 sputum samples (77.4%) from patients and 13 samples (41.9%) from healthy people were positive for H. influenzae type A. The increase in the severity of asthma symptoms, cough and shortness of breath showed that the severity of the infection decreased with the increase in asthma symptoms. Also, in terms of the asthma control test (ACT) score, spirometry indices, fractional exhaled nitric oxide index, and percentages of lymphocytes, macrophages, neutrophils and eosinophils, there was a significant difference between patients and healthy people (P=0.0001). Conclusion: Further studies are needed to determine the role of H. influenzae type A in the development of lung diseases, including asthma.