Characterization of the microbial community in indoor environments by chemical marker analysis: an update and critical evaluation

Abstract

We are developing an integrated methodology for characterizing the microbiology of indoor environments where specific microbial monomeric constituents in building materials and inhalable house dust particles are determined by using mass spectrometry-based methods. The methodology should represent a firm basis in research aiming to relate microbial exposure indoors to well-being and health.

Suppression of ionization and optimization of assay for 3‐hydroxy fatty acids in house dust using ion‐trap mass spectrometry

“…Our data suggest, however, that concentrations of long chain acids may have been overestimated in previous reports. The data from Zelles [1997] and a recent paper by Sebastian et al [2005] suggest that long chain 3-OHFAs may represent indicators of actinobacteria. Our data suggest that concentrations of certain of the long chain 3-OHFAs may be underestimated using ion trap mass spectrometry unless steps are taken to minimize ion suppression effects.…”

“…However, the method was not as sensitive as the TMS-based methods. 3-OHFAs as a marker of LPS in indoor environments have been studied extensively using TMS derivatization methods for which those presented here represent a refinement [Saraf et al, 1997;Fox et al, 2003Fox et al, , 2005Sebastian and Larsson, 2003;Park et al, 2004;Wady et al, 2004;Sebastian et al, 2005]. The strong correlation with Limulus bioassay in previous studies suggests that, although there may be some contribution from other sources, 3-hydroxy C10:0, C12:0, and C14:0 in house dust are primarily derived from gram-negative bacteria [Saraf et al, 1997].…”

Levels of microbial agents in floor dust during remediation of a water-damaged office building

“…Yeasts produce less ergosterol compared with filamentous fungi (Pasanen et al, 1999), and this may account in part for the discrepancy between ergosterol and hydrophilic fungal increases in 2007. Endotoxin is measured as biological potency of lipopolysaccharide originating from Gram-negative bacterial cell walls, and the bioactivity varies by species of Gram-negative bacteria (Sebastian et al, 2005). Although we did not have species information on Gram-negative bacteria in 2005 and 2007 surveys, it is possible that increases in levels of Gram-negative bacterial species were accompanied by a community shift toward species with less potent endotoxin in 2007, which might have resulted in no changes in endotoxin measurements.…”

Current State of the Science: Health Effects and Indoor Environmental Quality

“…These new methods are not yet fully developed and need to be evaluated (Keswani et al 2005; McDevitt et al 2004; Vesper et al 2004). Even if fungal and mold species can be identified more accurately in the environment, there are as yet no reliable markers of human exposure or dose for these and other biological agents; some efforts are under way to assess exposure using chemical markers or immunologic markers (Schmechel 2006; Sebastian et al 2005). …”