TABLE 3.
Specificity of the nylon-flocked-swab protocol compared to NASA standard protocola
| Recovery method | Actual spore inoculum (CFU; nominal, 100) | Mean recovery (CFU) | Range of recovery (CFU) | Recovery efficiency (%)b | 95% CI | Avg recovery (%)c |
|---|---|---|---|---|---|---|
| Nylon-flocked-swab protocol Ad | ||||||
| B. anthracis Sterne | 100.8 | 19.9 | 10.0-36.1 | 19.7 | 16.6-23.3 | 35.0 ± 3.2 (8.52) |
| B. atrophaeus | 100.5 | 45.4 | 35.0-55.0 | 45.2 | 40.2-50.7 | |
| B. megaterium | 88.8 | 26.3 | 15.0-55.1 | 29.6 | 25.5-34.1 | |
| B. megaterium 2c1 | 105.3 | 33.8 | 25.0-43.7 | 32.1 | 27.9-36.7 | |
| B. safensis | 103.7 | 26.8 | 32.5-48.8 | 25.8 | 22.2-29.9 | |
| B. thuringiensis | 96.1 | 36.6 | 10.0-47.6 | 38.1 | 33.9-42.7 | |
| B. thuringiensis E24 | 101.9 | 41.4 | 17.5-33.8 | 40.6 | 35.8-46.0 | |
| Nylon-flocked-swab protocol Bd | ||||||
| B. anthracis Sterne | 100.8 | 19.8 | 8.8-30.2 | 19.6 | 16.5-23.2 | 33.4 ± 5.9 (15.6) |
| B. atrophaeus | 99.1 | 50.6 | 36.2-61.2 | 51.1 | 45.9-56.8 | |
| B. megaterium | 101.0 | 20.6 | 13.7-30.0 | 20.4 | 17.3-24.0 | |
| B. megaterium 2c1 | 107.1 | 45.3 | 32.5-62.6 | 42.3 | 37.5-47.5 | |
| B. safensis | 102.5 | 26.4 | 11.3-43.8 | 25.7 | 22.1-29.9 | |
| B. thuringiensis | 89.4 | 14.8 | 7.5-22.6 | 16.5 | 13.5-20.0 | |
| B. thuringiensis E24 | 96.1 | 13.8 | 6.3-20.1 | 14.3 | 11.7-17.4 | |
| Cotton swab, NASA standard | ||||||
| B. anthracis Sterne | 100.8 | 6.5 | 2.5-12.5 | 6.5 | 4.8-8.5 | 11.4 ± 1.8 (4.66) |
| B. atrophaeus | 99.1 | 14.3 | 11.3-17.6 | 14.4 | 11.8-17.4 | |
| B. megaterium | 101.0 | 1.5 | 0.0-3.8 | 2.9 | 1.8-4.3 | |
| B. megaterium 2c1 | 107.1 | 14.6 | 6.2-21.2 | 13.7 | 11.2-16.5 | |
| B. safensis | 102.5 | 13.4 | 1.3-23.8 | 13.1 | 10.6-15.9 | |
| B. thuringiensis | 89.4 | 1.8 | 0.0-3.9 | 2.0 | 1.1-3.3 | |
| B. thuringiensis E24 | 96.1 | 3.0 | 1.3-6.3 | 3.1 | 2.0-4.7 |
a
Surface, stainless steel coupons; no. of replicates for each test, 10.
b
Recovery efficiency calculated from the mean number of recovered spores.
c
±Standard error of the mean (standard deviation). For further details, see Materials and Methods.
d
Protocol A was based on PBST for storage and vortexing for extraction; protocol B was based on water for storage and vortexing and sonification for extraction.