Remediating Office Environments of Spore-Forming Bacteria

Abstract

This study examines decontamination processes that were developed on an emergency basis to eliminate Bacillus anthracis spores from deliberately contaminated buildings. The recommended steps include a survey with sampling, the removal of sensitive items, and HEPA vacuuming of all readily available surfaces, followed by biocide treatment and subsequent analyses for viable cells. There are several analytical challenges posed by this approach. These include the ability to discriminate the added strain from naturally occurring resident microbes, determining detection limits for anthrax spores in settled dusts, and detecting viable but nonculturable spores. There are also logistical issues relating to the various skill sets required from investigation to reconstruction. In the present study, a model office was constructed, and a strain of Bacillus pumilus was isolated from the carpet and reintroduced to the office in excess. The abundance of the B. pumilus strain was monitored in settled dust using a strain-specific, quantitative polymerase chain reaction (QPCR)-based detection method following repeated HEPA vacuum cleanings. The QPCR method had a limit of detection corresponding to < or = 10(2) colony forming units per gram of settled dust. QPCR results were compared with measures of dust recoveries and fungal glucan and endotoxin levels in the dust samples. The largest fraction (ca. 81%) of added spores was recovered during the first HEPA cleaning. Subsequent cleanings resulted in incrementally lower recoveries, with removal of 93% of the initial inoculum by the third HEPA vacuuming. HEPA vacuuming prior to removal of items such as office contents and furnishings would result in much less resuspension of dust and limiting the extent of contamination. This approach also ensures that residual contaminants are as low as can be reasonably achieved.

Walker occupancy has an impact on changing airborne bacterial communities in an underground pedestrian space, as small-dust particles increased with raising both temperature and humidity

“…It is also feasible that large dust particles could become less buoyancy with increased weight. Recent studies showing a critical correlation of bacterial abundance with particle size in dust [ 32 – 34 ] support our hypothesis that small particles (less than 1.0 μm in size) could become a platform for bacteria, facilitating their circulation or survival in built environments. Thus, we found that the behavior of small particles was opposite to that of large particles in response to temperature and moisture changes.…”

Sick building syndrome (SBS) among office workers in a Malaysian university — Associations with atopy, fractional exhaled nitric oxide (FeNO) and the office environment

“…The samples were vortexed and shaken on a rotary shaker for 2.5 h (Johnson et al, 2010). The tubes were left to let the particles to settle and the supernatant were transferred into another depyrogenated tube.…”

“…Certified depyrogenated test tubes (Associates of Cape Cod, Falmouth, MA, USA) were used for all endotoxin and (1,3)-β-glucan testing. Other glassware, forceps and aluminium foil that used for samples preparation were depyrogenated by dry heat at 180°C for 12 h (Johnson et al, 2010).…”

Comparison of quantitative PCR and culture-based methods for evaluating dispersal of Bacillus thuringiensis endospores at a bioterrorism hoax crime scene

“…AUD$85 per sample). A qPCR targeted at the contaminating microorganism in question may also be particularly useful during remediation of endosporecontaminated sites, as culture-based analysis would not detect viable, non-culturable organisms [47]. An approach which includes Fig.…”