Evaluation of sponge wipe surface sampling for collection of potential surrogates for non-spore-forming bioterrorism agents.

Aim: Evaluate the efficacy of sponge wipe sampling at recovering potential bacterial surrogates for Category A and B non-spore-forming bacterial bioterrorism agents from hard, nonporous surfaces.

Methods: A literature survey identified seven nonpathogenic bacteria as potential surrogates for selected Category A and B non-spore-forming bacterial agents. Small (2 × 4 cm) and large (35.6 × 35.6 cm) coupons made from either stainless steel, plastic, or glass, were inoculated and utilized to assess persistence and surface sampling efficiency, respectively. Three commercially available premoistened sponge wipes (3M™, Sani-Stick®, and Solar-Cult®) were evaluated.

Results: Mean recoveries from persistence testing indicated that three microorganisms (Yersinia ruckeri, Escherichia coli, and Serratia marcescens) demonstrated sufficient persistence across all tested material types. Sampling of large inoculated (≥107 CFU per sample) coupons resulted in mean recoveries ranging from 6.6 to 3.4 Log10 CFU per sample. Mean recoveries for the Solar-Cult®, 3M™ sponge wipes, and Sani-Sticks® across all test organisms and all material types were ≥5.7, ≥3.7, and ≥3.4 Log10 CFU per sample, respectively. Mean recoveries for glass, stainless steel, and ABS plastic across all test organisms and all sponge types were ≥3.8, ≥3.7, and ≥3.4 Log10 CFU per sample, respectively.

Conclusions: Recovery results suggest that sponge wipe sampling can effectively be used to recover non-spore-forming bacterial cells from hard, nonporous surfaces such as stainless steel, ABS plastic, and glass.