Comparative Evaluation of Vacuum-based Surface Sampling Methods for Collection of Bacillus Spores
Citation:
Calfee, W., L. Rose, S. Morse, D. Mattorano, M. Clayton, A. Touati, N. Griffin-Gatchalian, C. Slone, AND N. McSweeney. Comparative Evaluation of Vacuum-based Surface Sampling Methods for Collection of Bacillus Spores. JOURNAL OF MICROBIOLOGICAL METHODS. Elsevier Science Ltd, New York, NY, 95(3):389-396, (2013).
Impact/Purpose:
Following a biological contamination incident, collection of surface samples is necessary to determine the extent and level of contamination, and to deem an area safe for reentry upon decontamination. Current sampling strategies targeting Bacillus anthracis spores prescribe vacuum-based methods for rough and/or porous surfaces. In this study, four commonly-used B. anthracis spore sampling devices (vacuum socks, 37 mm 0.8 µm MCE filter cassettes, 37 mm 0.3 µm PTFE filter cassettes, and 3MTM forensic filters) were comparatively evaluated for their ability to recover surface-associated spores. The vacuum sock device was evaluated at two sampling speeds (slow and fast), resulting in five total methods evaluated. Aerosolized spores (~105 cm-2) of a surrogate Bacillus species (Bacillus atrophaeus) were allowed to settle onto three material types (concrete, carpet, and upholstery). Ten replicate samples were collected using each vacuum method, from each of the three material types. In addition, stainless steel (i.e., nonporous) surfaces inoculated simultaneously were sampled with pre-moistened wipes. Recoveries from wipes of steel surfaces were utilized to verify the inoculum, and 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. Relative recoveries were compared by one-way and three-way ANOVA. Data analysis by one-way ANOVA 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, these results were not found to be statistically significant. Analysis by three-way ANOVA suggested that no method was superior for any of the materials tested. The results of this study may be used to guide selection of sampling approaches following a biological contamination incident.
Description:
Journal Article
URLs/Downloads:
COMPARATIVE EVALUATION OF VACUUM-BASED SURFACE SAMPLING METHODS FOR COLLECTION OF BACILLUS SPORES
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