TABLE 3.
Origin and designations of U.S. clinical specimens used for evaluation of the real-time PCR assay for detection of the A and B subunits of the tox gene
| CDC no. | Origin | Date collected (mo-yr) | Initial standard PCRa | Final standard PCRb | Real-time PCR | Reamplification by standard PCR | tox sequence confirmed by DNA sequencingf |
|---|---|---|---|---|---|---|---|
| a22 | Nevada | 4-97 | B | −g | − | ||
| a27 | Nevada | 4-97 | B | − | A/B | Yes | Yes |
| a28 | Nevada | 4-97 | B | − | A/B | Yes | Yes |
| a33 | Oregon | 4-97 | A/B | A | A | Yes | Yes |
| a34 | Oregon | 4-97 | A/B | A/B | B | Yes | Yes |
| a35 | Oregon | 4-97 | B | − | B | Yes | Yes |
| a36 | Oregon | 4-97 | A/B | − | B | Yes | Yes |
| a40 | Nevada | 4-97 | A/B | − | − | ||
| a45 | Minnesota | 4-97 | B | tr/− | Ac | Yes | Yes |
| a46 | Minnesota | 4-97 | B | tr/− | Ac | Yes | Yes |
| a53 | New York | 4-97 | B | − | Ac | Yes | Yes |
| a85 | Nevada | 4-97 | A | − | A/B | Yes | Yes |
| a180 | Nevada | 5-97 | A | − | A | Yes | Yes |
| a319 | Nevada | 6-97 | A/B | − | A/B | Yes | Yes |
| a629 | Oregon | 5-98 | A/B | − | A | Yes | Yes |
| a772d | North Carolina | 12-99 | − | A/B | Yes | Yes | |
| c1 | Dominican Republic | 1-00 | − | A/B | Yes | Yes | |
| c2 | Dominican Republic | 1-00 | − | A | Yes | Yes | |
| a773e | Georgia | 1-00 | − | B | Yes | Yes | |
| a774e | Georgia | 1-00 | − | B | Yes | Yes | |
| a775e | Georgia | 1-00 | − | A/B | Yes | Yes | |
| a780 | North Carolina | 3-00 | − | A/B | Yes | Yes | |
| c10 | Dominican Republic | 5-00 | − | A/B | Yes | Yes | |
| c11 | Dominican Republic | 5-00 | A/B | A/B | NDh | ND | |
| c12 | Dominican Republic | 5-00 | A/B | A/B | ND | ND | |
| c13 | Dominican Republic | 5-00 | A/B | A/B | ND | ND | |
| c14 | Dominican Republic | 5-00 | − | A | Yes | Yes | |
| c15 | Dominican Republic | 5-00 | − | A | Yes | Yes | |
| c16 | Dominican Republic | 5-00 | − | A | Yes | Yes | |
| c17 | Dominican Republic | 5-00 | − | A | Yes | Yes | |
| b1 | Russia | 6-00 | A/B | A/B | ND | ND | |
| b2 | Russia | 6-00 | A/B | A/B | ND | ND | |
| b3 | Russia | 6-00 | A/B | A/B | ND | ND | |
| b4 | Russia | 6-00 | A/B | A/B | ND | ND | |
| b5 | Russia | 6-00 | A/B | A/B | ND | ND | |
| b6 | Russia | 6-00 | A/B | A/B | ND | ND | |
| a806 | Mississippi | 6-00 | − | A/B | Yes | Yes | |
| a807 | Mississippi | 6-00 | − | A/B | Yes | Yes |
a
Standard PCR analyses were performed at the time the specimens were collected for diagnostic purposes as described by Nakao and Popovic (10).
b
Result at the time of the retest (January to June 2000) or at the time the specimen was received. tr, trace.
c
Indicates discrepancy between the real-time PCR result and the standard PCR result.
d
Paraffin-embedded specimen.
e
a773 to a775 were sections taken from different regions of a single pseudomembrane tissue specimen.
f
Sequences compared to those published by Nakao et al. (9).
g
-, negative result.
h
ND, not determined.