Comparative evaluation of vacuum-based surface sampling methods for collection of Bacillus spores

Abstract

In this study, four commonly-used sampling devices (vacuum socks, 37 mm 0.8 μm mixed cellulose ester (MCE) filter cassettes, 37 mm 0.3 μm polytetrafluoroethylene (PTFE) filter cassettes, and 3M™ forensic filters) were comparatively evaluated for their ability to recover surface-associated spores. Aerosolized spores (~105 CFU cm−2) of a Bacillus anthracis surrogate were allowed to settle onto three material types (concrete, carpet, and upholstery). Ten replicate samples were collected using each vacuum method, from each material type. Stainless steel surfaces, inoculated simultaneously with test materials, were sampled with pre-moistened wipes. Wipe recoveries were utilized to normalize vacuum-based recoveries across trials. Recovery (CFU cm−2) and relative recovery (vacuum recovery/wipe recovery) were determined for each method and material type. Recoveries and relative recoveries ranged from 3.8 × 103 to 7.4 × 104 CFU cm−2 and 0.035 to 1.242, respectively. ANOVA results indicated that the 37 mm MCE method exhibited higher relative recoveries than the other methods when used for sampling concrete or upholstery. While the vacuum sock resulted in the highest relative recoveries on carpet, no statistically significant difference was detected. The results of this study may be used to guide selection of sampling approaches following biological contamination incidents.

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters

“…2B), were utilized according to the methods reported previously (Calfee et al, 2013). For each sample, the centermost 30.5 × 30.5 cm portion of the inoculated HVAC filter was sampled by lightly pressing the angled tube to the filter surface and traversing the filter coupon at a rate of 3 to 5 s per linear foot.…”

Urban Fate and Transport Modeling of Contaminants: The Unique Needs of Emergency Response and the Potential for Adapting Existing Models

“…Geiger counters provide rapid indication of the presence and intensity of radioactive material, allowing for quick assessment of contamination. Biological sampling can be much more time consuming due to the need for precise collection techniques such as vacuuming and swabbing (Calfee et al 2013;Tufts et al 2014). This activity is further complicated because of the limited number of certified laboratories capable of analyzing biological agents.…”

Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

“…After the 2001 anthrax incident, several research groups developed sampling and analysis methods and investigated (in laboratory studies) the performance of those methods using swab, wipe, and vacuum sampling devices for B. anthracis surrogates on various surfaces (Almeida et al 2008;Brown et al 2007aBrown et al , 2007bBrown et al , 2007cButtner et al 2001;Buttner et al 2004aButtner et al , 2004bCalfee et al 2013;Edmonds 2009;Edmonds et al 2009;Estill et al 2009;Frawley et al 2008;Hodges et al 2006;Krauter et al 2012;Lewandowski et al 2010;Nellen et al 2006;Perry et al 2013;Quizon et al 2007;Rose et al 2004;Sanderson et al 2004;Valentine et al 2008;Valiante et al 2003). In addition, the CDC performed validation studies on macrofoam-swab (Hodges et al 2010) and cellulose-sponge-wipe (Rose et al 2011) sampling methods.…”