A new study published in International Archives of Allergy and Immunology aimed to elucidate the effect of bacterial infections on bronchial asthma.

In this study, pharyngeal bacterial colonization, duration of wheezing and serum levels of cytokines and chemokines were examined during acute exacerbations ofbronchial asthma in 111 children.Potential bacterial pathogens were investigated in pharyngeal samples and viruses obtained from nasal secretions of outpatients and/or in patients with acute exacerbationsof asthma. Serum levels of 27 different cytokines/chemokines were also measured.

The results showed positive pharyngeal bacterial cultures in 110 children. The three major bacterial pathogens were Streptococcus pneumoniae (29.7%), Moraxella catarrhalis (11.7%)and Haemophilus influenzae (10.8%). M. catarrhalis was detected more frequently in those with pneumonia.Additionally, patients with S. pneumoniae colonization had significantly shorter wheezing episodes than those without. On the contrary, the duration of wheezing did not differ significantly among cases with other bacteria such as M. catarrhalis and H. influenzae. While the length of wheezing episode in patients with S. pneumoniae colonization showed significant inverse correlation with peripheral white blood cell count, neutrophil count and C-reactive protein. There was no significant correlation between the duration of wheezing and these three parameters among patients with M. catarrhalis or H. influenza. Among the 27 cytokines/chemokines, only serum tumor necrosis factor (TNF)-α was significantly lower in patients with S. pneumoniae colonization than in those without it.

It was inferred that pharyngeal S. pneumoniae colonization plays a suppressive role on the pathophysiology during acute exacerbations of asthma.