False Negative Rates of a Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates via Real-Time PCR

Hutchison, Janine R.¹  Piepel, Gregory F.¹  Amidan, Brett G.¹  Sydor, Michael A.¹  Deatherage Kaiser, Brooke L¹ 

[1] Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

关键词: False negative rate;    Bacillus anthracis;    Macrofoam swab;    PCR;   

DOI  :  10.2172/1186982
RP-ID  :  PNNL--24204 Rev0
PID  :  OSTI ID: 1186982
Others  :  Other: 400904120

美国|英语

来源: SciTech Connect

【 摘 要 】

Surface sampling for Bacillus anthracis spores has traditionally relied on detection via bacterial cultivation methods. Although effective, this approach does not provide the level of organism specificity that can be gained through molecular techniques. False negative rates (FNR) and limits of detection (LOD) were determined for two B. anthracis surrogates with modified rapid viability-polymerase chain reaction (mRV-PCR) following macrofoam-swab sampling. This study was conducted in parallel with a previously reported study that analyzed spores using a plate-culture method. B. anthracis Sterne (BAS) or B. atrophaeus Nakamura (BG) spores were deposited onto four surface materials (glass, stainless steel, vinyl tile, and plastic) at nine target concentrations (2 to 500 spores/coupon; 0.078 to 19.375 colony-forming units [CFU] per cm??). Mean FNR values for mRV-PCR analysis ranged from 0 to 0.917 for BAS and 0 to 0.875 for BG and increased as spore concentration decreased (over the concentrations investigated) for each surface material. FNRs based on mRV-PCR data were not statistically different for BAS and BG, but were significantly lower for glass than for vinyl tile. FNRs also tended to be lower for the mRV-PCR method compared to the culture method. The mRV-PCR LOD?????? was lowest for glass (0.429 CFU/cm?? with BAS and 0.341 CFU/cm?? with BG) and highest for vinyl tile (0.919 CFU/cm?? with BAS and 0.917 CFU/cm?? with BG). These mRV-PCR LOD?????? values were lower than the culture values (BAS: 0.678 to 1.023 CFU/cm?? and BG: 0.820 to 1.489 CFU/cm??). The FNR and LOD?????? values reported in this work provide guidance for environmental sampling of Bacillus spores at low concentrations.