Microbial Contents of Vacuum Cleaner Bag Dust and Emitted Bioaerosols and Their Implications for Human Exposure Indoors

Abstract

Vacuum cleaners can release large concentrations of particles, both in their exhaust air and from resuspension of settled dust. However, the size, variability, and microbial diversity of these emissions are unknown, despite evidence to suggest they may contribute to allergic responses and infection transmission indoors. This study aimed to evaluate bioaerosol emission from various vacuum cleaners. We sampled the air in an experimental flow tunnel where vacuum cleaners were run, and their airborne emissions were sampled with closed-face cassettes. Dust samples were also collected from the dust bag. Total bacteria, total archaea, Penicillium/Aspergillus, and total Clostridium cluster 1 were quantified with specific quantitative PCR protocols, and emission rates were calculated. Clostridium botulinum and antibiotic resistance genes were detected in each sample using endpoint PCR. Bacterial diversity was also analyzed using denaturing gradient gel electrophoresis (DGGE), image analysis, and band sequencing. We demonstrated that emission of bacteria and molds (Penicillium/Aspergillus) can reach values as high as 1E5 cell equivalents/min and that those emissions are not related to each other. The bag dust bacterial and mold content was also consistent across the vacuums we assessed, reaching up to 1E7 bacterial or mold cell equivalents/g. Antibiotic resistance genes were detected in several samples. No archaea or C. botulinum was detected in any air samples. Diversity analyses showed that most bacteria are from human sources, in keeping with other recent results. These results highlight the potential capability of vacuum cleaners to disseminate appreciable quantities of molds and human-associated bacteria indoors and their role as a source of exposure to bioaerosols.

Ultrafine Particles in Residential Indoors and Doses Deposited in the Human Respiratory System

“…Possibly, it can be originated both from the dust collected in the dust bag and from the emission from the vacuum motor. This finding agrees with other studies [26,27], which showed that vacuuming can be a source of indoor exposure to biological and non-biological aerosols. The authors measured UFP emission rates in the range from 4.0 × 10 .…”

“…This is a well-documented technique for generating UFPs with modes in the size distributions at about 10 nm or below [28]. According to this finding Knibbs et al [26] and Veillette et al [27] measured count median diameter (CMD) as low as 15 nm: they concluded that particle emission from the motors of vacuum cleaners is very likely the dominant UFP production mechanism. For such reasons, very likely, the mode at 10 nm in the size distribution for vacuum cleaning in Figure 2a is due to particle emission from the vacuum motor.…”

Abundance of Mycobacterium avium ssp. hominissuis in soil and dust in Germany - implications for the infection route

“…) and because vacuuming can release large amounts of aerosols and is also responsible for whirling up of settled dust (Veillette et al . ). The microbial composition of home dust is determined by contributing sources such as soil, sand, food debris, skin particles, hair or water aerosols.…”

Sources and dynamics of fluorescent particles in hospitals

“…This finding is also supported by Clark et al., who found an increase in airborne bacteria during cleaning. Vacuum bags can be an important reservoir for bacteria, molds, endotoxins and allergens, and they can release large numbers of particles, both in their exhaust air and from the resuspension of settled dust . Studies suggest that emission and aerosolization of dust during vacuuming can spread microorganisms such as Salmonella spp.…”