A Method for Detecting Fungal Contaminants in Wall Cavities

Abstract

This article describes a practical method for detecting the presence of both fungal spores and culturable fungi in wall cavities. Culturable fungi were collected in 25 mm cassettes containing 0.8 microm mixed cellulose ester filters using aggressive sampling conditions. Both culturable fungi and fungal spores were collected in modified slotted-disk cassettes. The sample volume was 4 L. The filters were examined microscopically and dilution plated onto multiple culture media. Collecting airborne samples in filter cassettes was an effective method for assessing wall cavities for fungal contaminants, especially because this method allowed the sample to be analyzed by both microscopy and culture media. Assessment criteria were developed that allowed the sample results to be used to classify wall cavities as either uncontaminated or contaminated. As a criterion, wall cavities with concentrations of culturable fungi below the limit of detection (LOD) were classified as uncontaminated, whereas those cavities with detectable concentrations of culturable fungi were classified as contaminated. A total of 150 wall cavities was sampled as part of a field project. The concentrations of culturable fungi were below the LOD in 34% of the samples, whereas Aspergillus and/or Penicillium were the only fungal genera detected in 69% of the samples in which culturable fungi were detected. Spore counting resulted in the detection of Stachybotrys-like spores in 25% of the samples that were analyzed, whereas Stachybotrys chartarum colonies were only detected on 2% of malt extract agar plates and on 6% of corn meal agar plates.

High incidence of Aspergillus and Penicillium spores in the atmosphere of the cave of Nerja (Malaga, southern Spain)

“…Many comparative studies between spore-sampling devices were found in the literature (Burge 1990;Li and Lin 1999;Morris et al 2000;Wang et al 2001;Spurgeon 2003;Wüst et al 2003). Although some authors consider Hirsttype samplers to be of little use for particles smaller than 5 mm (Spieksma 1995), this type of sampler allows a continuous study, hour by hour, for a long period of time (4 years in this case), the results being available almost immediately after the sample collection (Baxter et al 2005), unlike other types of spore traps, with time restriction records, and whose samples need to be incubated for several days.…”

Multigene phylogeny reveals new lineage for Stachybotrys chartarum, the indoor air fungus

“…In recent years this species has achieved notoriety as an airborne house-inhabiting fungus that produces mycotoxins and can cause serious illness and even death in humans (Vesper et al 2000). Considerable effort is given to monitoring the presence of this fungus particularly in situations where building interiors, especially substrates rich in cellulose, have become wet, thus supporting the growth of this and other mycotoxin-producing molds (Andersen, Nielsen & Jarvis 2002, Shelton et al 2003, Spurgeon 2003.…”

Fungal Contamination of Building Materials and the Aerosolization of Particles and Toxins in Indoor Air and Their Associated Risks to Health: A Review

“…It should be noted that most of these studies were carried out in mouldy dwellings or dwellings in which inhabitants displayed respiratory problems [ 9 , 67 , 72 , 73 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ]. Data are less numerous on normal buildings with no dampness, no visible mould contamination and no respiratory problems for occupants [ 63 , 66 , 75 , 76 , 81 , 82 , 87 , 88 ]. Only a few studies were performed in other types of buildings, such as hospitals, archives and museums [ 64 , 89 , 90 , 91 , 92 , 93 , 94 , 95 ].…”