Role of bacterial flora in upper respiratory tracts of patients with bronchial asthma.

Abstract

Most allergists agree that there are many patients with bronchial asthma accompanied by bacterial infections, and the infections play some role in asthma. Aggravating effects of bacterial infections is particularly evident in bronchial asthma of older patients and in many cases of status asthmaticus. However, there is no agreement among allergists as to the mechanism of bacterial effects on the asthmatic attacks. Varying explanations were proposed, including bacterial allergy, bronchospasm due to irritative actions of inflammation or bacterial products, and modification of the process or state of the sensitization to allergens in the presence of infection. The purpose of this study was to evaluate the role of bacterial antigens in the patients with bronchial asthma. The present paper is mainly concerned with the age distribution of positive skin reaction to the bacterial antigens. The species of bacteria found in patients’ sputum or nasal mucus have shown little differences from control subjects. Streptococcus viridans and Neisseria were found most frequently, and Hemophylus and others were detected less frequently. In nasal mucus cultures, however, Corynebacteria, Str. viridans and Staphylococcus albus were most dominant. Eight species of these bacteria were selected for testing skin reactions of the asthmatics and control subjects. The incidence of positive immediate skin reactions to the bacterial antigens in the patients was about 40 per cent, and it was significantly higher than that in control subjects. House dust extracts and four air borne fungi gave 60 per cent and 37 per cent positive skin rcactions respectively. The incidence of positive skin reactions to the common inhalant allergens such as house dust, pollen or airborne fungi was studied in different age groups. There was a significant difference in the incidence of the reactions in the different age groups, and the incidence was much higher in younger patients than in older ones. For instance, 82.1 per cent of patients in the first decade and 27.3 per cent of patients in the sixth decade gave positive reactions. However, in the relationship between the incidence of positive immediate skin reactions to the bacterial antigens and the patient’s age at onset of the disease, there was a little, but not a significant difference of the incidence of positive skin reactions in the ages of onset. For instance, 48 per cent of patients in the first decade and 26 per cent of patients in the sixth decade gave positive skin reactions to bacterial antigens.