TABLE 1.
Correlation between erm(41) genotype and macrolide phenotypic susceptibility for selected M. chelonae-abscessus] complex isolates
| ITSa identification (n) | 14-day clarithromycin susceptibilitiesb of isolates (no. [%]) |
erm(41) genotype | ||
|---|---|---|---|---|
| Susceptible (MIC ≤ 2 μg/ml) | Intermediate (MIC 4 μg/ml) | Resistant (MIC ≥ 8 μg/ml) | ||
| M. chelonae (45) | 44 (97.8) | 1 (2.2) | 0 | Not present |
| M. abscessus group (285) | 74 (26) | 2 (0.7) | 0 | C28 sequevar |
| 0 | 0 | 94 (33.0) | T28 sequevar | |
| 114 (40) | 1 (0.3) | 0 | Deletionsc | |
a
ITS, internal transcribed spacer.
b
All sequenced isolates were clarithromycin susceptible after 72 h of incubation in an attempt to eliminate organisms with acquired macrolide resistance due to rrl mutation.
c
Observed deletions, which always occurred together, included deletions at nucleotides 64 and 65 and a deletion of 274 bp starting from nucleotide 159 (using the GTG start codon as nucleotide 1).