The Importance of Bacterial and Viral Infections Associated with Adult Asthma Exacerbations in Clinical Practice

Abstract

BackgroundViral infection is one of the risk factors for asthma exacerbation. However, which pathogens are related to asthma exacerbation in adults remains unclear.ObjectiveThe relation between various infections and adult asthma exacerbations was investigated in clinical practice.MethodsThe study subjects included 50 adult inpatients due to asthma exacerbations and 20 stable outpatients for comparison. The pathogens from a nasopharyngeal swab were measured by multiplex PCR analysis.ResultsAsthma exacerbations occurred after a common cold in 48 inpatients. The numbers of patients with viral, bacterial, or both infections were 16, 9, and 9, respectively. The dominant viruses were rhinoviruses, respiratory syncytial virus, influenza virus, and metapneumovirus. The major bacteria were S. pneumoniae and H. influenzae. Compared to pathogen-free patients, the patients with pathogens were older and non-atopic and had later onset of disease, lower FeNO levels, lower IgE titers, and a higher incidence of comorbid sinusitis, COPD, or pneumonia. Compared to stable outpatients, asthma exacerbation inpatients had a higher incidence of smoking and comorbid sinusitis, COPD, or pneumonia. Viruses were detected in 50% of stable outpatients, but a higher incidence of rhinovirus, respiratory syncytial virus, and metapneumovirus infections was observed in asthma exacerbation inpatients. H. influenzae was observed in stable asthmatic patients. Other bacteria, especially S. pneumoniae, were important in asthma exacerbation inpatients.ConclusionViral or bacterial infections were observed in 70% of inpatients with an asthma exacerbation in clinical practice. Infection with S. pneumoniae was related to adult asthma exacerbation.

Asthma Exacerbation Caused by Bacterial Infection in Two Elderly Patients

“…Similar to previous findings [7][8][9], bacteria were detected in the sputum in these cases. In addition, the number of eosinophils in the peripheral blood and sputum was low, and the patients presented with neutrophilia.…”

“…Bacteria detected in these cases and in previous reports [7][8][9] enhance mucus secretion [15], inhibit the ciliary beat frequency, and cause airway epithelial injury, thereby impairing mucociliary clearance [16]. Infection with these bacteria also stimulates the cells in the airways and the lung parenchyma to induce pro-inflammatory substrates such as interleukin (IL)-8 and leukotriene B4 [17].…”

“…Among airway infections, viral infections such as rhinoviruses are major causes of asthma exacerbation [3][4][5][6]. Airway infections by bacteria, such as Streptocccus pneumoniae and Haemophilus influenzae, have also been found in patients with asthma exacerbation [7,8]. However, the role of bacterial infections in asthma exacerbation is less clear [9] and has received less attention than that of viruses [10].…”

Viruses and bacteria in Th2‐biased allergic airway disease

“…In atopic Turkish children with asthma and allergic rhinitis, significantly higher herpes simplex type 1 (HSV-1) IgG seropositivity was detected in the serum than in the matched nonatopic group (13), suggesting a possible relationship between pediatric allergic airway diseases and HSV-1 infections. In adults, higher incidences of HRV-A/B/C, HRSV-A, and metapneumovirus infections were observed in nasopharyngeal swabs during asthma exacerbations (14).…”

“…It is evident that bacterial organisms act as important contributors to asthma exacerbations. A study of the bacterial composition of the nasopharynx in adult asthmatic patients indicated that Streptococcus pneumoniae infection was also associated with asthma exacerbations in clinical practice (14). In CRS, inflammation development takes place in the middle meatus.…”