TABLE 1.
L. monocytogenes isolates used to develop an SNP genotyping assay to differentiate isolates with and without a PMSC in inlA
| Isolatea | Amino acid positionb corresponding to inlA PMSC (mutation type) | Reference |
|---|---|---|
| FSL F2-539 (wild type) | No inlA PMSC | 10 |
| Natural isolates | ||
| FSL F2-563 | 606 (1) | 26 |
| FSL R2-074 | 656 (2) | 26 |
| FSL F2-515 | 700 (3) | 26 |
| FSL F2-640 | 9 (4) | 29 |
| FSL R2-080 | 189 (5) | This study |
| FSL T1-045 | 492 (6) | This study |
| FSL T1-061 | 562 (7) | This study |
| NV8 | 460 (8) | 33 |
| NV7 | 519 (9) | 33 |
| NV4 | 677 (10) | 33 |
| NV5 | 685 (11) | 33 |
| L028 | 576 (12) | 14 |
| 36-25-1 | 527 (13) | 12 |
a
The isolate described as the wild type was a laboratory control strain (EGD-e) that carried full-length inlA, whereas isolates described as natural were isolated from food samples and carried naturally occurring mutations that led to a PMSC in inlA. We did not detect the presence of mutations leading to a PMSC in inlA from isolates NV4 and NV7, which were previously reported to harbor PMSC mutations 10 and 9, respectively (33), by using inlA sequencing or the SNP genotyping assay, even after obtaining multiple DNA samples.
b
Amino acid numbering is relative to the sequence of the wild-type control strain EGD-e.