Evaluation of Bacillus anthracis and Yersinia pestis sample collection from nonporous surfaces by quantitative real‐time PCR |
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Authors: | E Hong‐Geller YE Valdez Y Shou TM Yoshida BL Marrone JM Dunbar |
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Institution: | Biosciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA |
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Abstract: | Aim: We will validate sample collection methods for recovery of microbial evidence in the event of accidental or intentional release of biological agents into the environment. Methods and Results: We evaluated the sample recovery efficiencies of two collection methods – swabs and wipes – for both nonvirulent and virulent strains of Bacillus anthracis and Yersinia pestis from four types of nonporous surfaces: two hydrophilic surfaces, stainless steel and glass, and two hydrophobic surfaces, vinyl and plastic. Sample recovery was quantified using real‐time qPCR to assay for intact DNA signatures. We found no consistent difference in collection efficiency between swabs or wipes. Furthermore, collection efficiency was more surface‐dependent for virulent strains than nonvirulent strains. For the two nonvirulent strains, collection efficiency was similar between all four surfaces, albeit B. anthracis Sterne exhibited higher levels of recovery compared to Y. pestis A1122. In contrast, recovery of B. anthracis Ames spores and Y. pestis CO92 from the hydrophilic glass or stainless steel surfaces was generally more efficient compared to collection from the hydrophobic vinyl and plastic surfaces. Conclusions: Our results suggest that surface hydrophobicity may play a role in the strength of pathogen adhesion. The surface‐dependent collection efficiencies observed with the virulent strains may arise from strain‐specific expression of capsular material or other cell surface receptors that alter cell adhesion to specific surfaces. Significance and Impact of the Study: These findings contribute to the validation of standard bioforensics procedures and emphasize the importance of specific strain and surface interactions in pathogen detection. |
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Keywords: | Bacillus anthracis bioforensics nonporous surfaces qPCR sample collection Yersinia pestis |
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