Quantitative determination of airborne microorganisms comprises using a portable collecting device and a modified commercial Aspergillus immunoassay

摘要

Quantitative determination of a galactomannan antigen expressed by airborne Aspergillus spores or other airborne microorganisms comprises using a portable collecting device and a commercial Aspergillus immunoassay. Quantitative determination of a galactomannan antigen expressed by airborne Aspergillus spores or other airborne microorganisms comprises using a portable collecting device and a commercial Aspergillus immunoassay. The method comprises: (a) collecting the spores in a battery-operated device comprising a filter membrane, the device being carried on the clothing of a person while working or being located in an enclosed space, such that 40-70 liters/hour of ambient air is drawn through the filter membrane; (b) extracting the membrane with a liquid; and (c) subjecting the extract to a modified Platelia (RTM) Aspergillus assay. The Aspergillus assay has the following modifications: (i) heat treatment at 100 deg C for 3 minutes is omitted; (ii) a galactomannan standard of 0.5-6.5 ng and a reference sample in the form of a liquid extract of an unused filter membrane are used instead of a cut-off sample; (iii) the antigen is detected within a few hours without a culture step; (iv) dilutions are performed to embrace the linear response range of the assay; and (v) spore digestion is performed to determine soluble and cell-wall-bound antigen, where the detection limit is reduced to 1 ng/ml. An Independent claim is also included for an air-filtration germ collection device for the above method, comprising a cylindrical housing with a diameter of 30-50 mm and a length of 60-100 mm which contains a filter membrane and a battery-operated radial fan, the device having a total weight of 90-100 g.