Table VI.
Results of molecular identification of resistance mechanisms to clarithromycin by GenoType NTM in relation to phenotypic susceptibility testing results.
| No. of strain | Species | GenoType NTM-DR results | Phenotypic results of susceptibility to clarithromycin | |
|---|---|---|---|---|
| Type of bands (WT or mutation) | Molecular mechanisms of resistance (Yes/No) | |||
| 1 | Mabs | erm(41) C28 rrlWT | No | (S) |
| 2 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
| 3 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
| 4 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
| 5 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
| 6 | Mmas | erm(41)T28 rrlWT | Yes | (R) |
| 7 | Mmas | erm(41)T28* rrlWT | No | nt |
| 8 | Mmas | erm(41)T28* rrlWT | No | (S) |
| 9 | Mabs | erm(41)T28 rrlMUT | Yes | (S) |
| 10 | Mb ol | erm(41)T28* rrlWT | No | (S) |
| 11 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
| 12 | Mabs | erm(41)T28 rrlWT | Yes | (R) |
1
Mabs – Mycobacterium abscessus subsp. abscessus,
1
Mmas – Mycobacterium abscessus subsp. massiliense,
1
Mbol – Mycobacterium abscessus subsp. bolletii
1
S – susceptible, R – resistant, nt – not tested
1
* – due to the deletion in the erm(41) gene, M. abscessus subs. massiliense the gene is non-functional, leading to macrolide sensitivity regardless of the resulting erm(41) T28 band (except strains with the rrl mutation)