|Description:||Under a low magnification of 28x, this 2007 scanning electron microscopic (SEM) image depicted the fibrous configuration of a plain uninoculated cotton swab. This swab, as well as three other materials, including macrofoam (see PHIL 9736, 9737, 9738), polyester (see PHIL 9735), and rayon (see PHIL 9734) were scanned for a CDC study involving their efficiency in recovery of Bacillus anthracis bacterial spores from steel coupons that had been inoculated with a spore suspension of known concentration. See PHIL 9733, for another view of this material. The article discussing the description of this swab material analysis, and the analytical results was published in ”Emerging Infectious Diseases”, Vol. 10, No. 6, June, 2004, and was entitled, Swab Materials and Bacillus anthracis Spore Recovery from Nonporous Surfaces. A link to this article is found below.|
Results indicated that premoistened swabs were more efficient at recovering spores than dry swabs, i.e., 14.3% vs. 4.4%. Vortexing swabs for 2 min. during processing resulted in superior extraction of spores when compared to sonicating them for 12 min., or subjecting them to minimal agitation. Premoistened macrofoam and cotton swabs that were vortexed during processing recovered the greatest proportions of spores with a mean recovery of 43.6% (standard deviation [SD] 11.1%), and 41.7% (SD 14.6%), respectively. Premoistened and vortexed polyester and rayon swabs were less efficient, at 9.9% (SD 3.8%) and 11.5% (SD 7.9%), respectively.