Bacillus subtilis Enzymes: a 7-year Clinical, Epidemiological and Immunological Study of an Industrial Allergen

Abstract

A survey of 1642 workers in a factory producing enzyme washing powders from 1968 to 1975 has shown that reduction of total dust and enzyme dust levels, combined with full implementation of the Soap and Detergent Industry Association recommendations, have eliminated detectable respiratory illness. Previous findings, that atopic subjects were more likely than non-atopies to become skin prick-test positive (PT+) to a standardized enzyme reagent, have been confirmed. After excluding atopies from such work the percentage converting to PT+ has steadily fallen. Individuals with only a PT+ have no clinical symptoms and do not react in any way to the working environment. Of all employees working throughout this period, 82 per cent (1354 out of 1642 tested) have remained prick-test negative. It is shown that repeated prick testing with the same allergen does not induce allergic skin reactivity. There is a good correlation between prick-test results and the results of serological tests for enzyme specific IgE. There is no evidence of any difference in changes in the ventilatory capacities of prick-test positive as against prick-test negative employees, or that positivity alone is a contraindication to working with these products. Varying degrees of contact or lengths of exposure to enzymes do not produce any statistically significant differences in changes in lung function. The survey does not reveal any evidence of longer-term obstructive bronchial disease.