Evaluation of Surface Sampling for Bacillus Spores Using Commercially Available Cleaning Robots

Abstract

Five commercially available domestic cleaning robots were evaluated on their effectiveness for sampling aerosol-deposited Bacillus atrophaeus spores on different indoor material surfaces. The five robots tested include three vacuum types (R1, R2, and R3), one wet wipe (R4), and one wet vacuum (R5). Tests were conducted on two different surface types (carpet and laminate) with 10(6) colony forming units of B. atrophaeus spores deposited per coupon (35.5 cm × 35.5 cm). Spores were deposited on the center surface (30.5 × 30.5 cm) of the coupon's total surface area (71.5 × 71.5 cm), and the surfaces were sampled with an individual robot in an isolation chamber. Chamber air was sampled using a biofilter sampler to determine the potential for resuspension of spores during sampling. Robot test results were compared to currently used surface sampling methods (vacuum sock for carpet and sponge wipe for laminate). The test results showed that the average sampling efficacies for R1, R2, and R3 on carpet were 26, 162, and 92% of vacuum sock sampling efficacy, respectively. On laminate, R1, R2, R3, R4, and R5 average sampling efficacies were 8, 11, 2, 62, and 32% of sponge wipe sampling efficacy, respectively. We conclude that some robotic cleaners were as efficacious as the currently used surface sampling methods for B. atrophaeus spores on these surfaces.

Extraction of Aerosol-Deposited Yersinia pestis from Indoor Surfaces To Determine Bacterial Environmental Decay

“…3C). Even though the relative recovery efficiency associated with carpet was significantly lower than that with other surfaces, the total yield was consistent with previously published reports (18,29,30). Lastly, considering the extraction buffer volume and reliable counting standard, the liquid extraction with CFU plating had a limit of detection (LOD) of 100 CFU/ coupon, which was confirmed by performing liquid deposition LOD experiments for all four surfaces (Fig.…”

“…In 2008, Sinclair et al published an extensive review of all previous studies evaluating the environmental stability of several infectious agents, both bacterial and viral, on indoor and outdoor surfaces utilizing either liquid or aerosol deposition (13). Most of the studies utilized liquid deposition of agent onto coupons rather than aerosol deposition to evaluate agent stability, which does not mimic a deposition of respirable aerosol particles onto surfaces (1,(14)(15)(16)(17)(18). In addition, the majority of surface stability studies have focused on enteric pathogens in food protection studies (15,(19)(20)(21)(22).…”

Sampling and inactivation of wet disseminated spores from flooring materials, using commercially available robotic vacuum cleaners

“…If the carpet in our study had been sampled using the vacuum‐based method, the collection efficiencies of the robots in comparison would have increased by a factor of 10 3 , giving a recovery percentage closer to that seen by Lee et al . ().…”

“…The Lee et al study derived its results by comparing robot results to the recovery from surface sampling, in a similar way to this study; however Lee et al used a vacuumbased method for recovering from carpet, whereas we employed a water-soluble tape method. (Lee et al 2013).…”

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

“…Such an advantage may be desirable when collecting vast numbers of samples, such as during characterization sampling following a wide-area incident (Buttner et al, 2004; Franco and Bouri, 2010; Schmitt and Zacchia, 2012). It has been suggested that using robotic sampler to generate composite samples could decrease the amount of effort expended by both sample collection teams and analysis laboratories (Lee et al, 2013). …”