Table 2. Characteristics and in vitro antibacterial activities of four potential AMPs against 16 clinical isolates of M. abscessus.
| Isolates | Organism | Subspeciesa | Colony morphology | DST profile, MIC value (μg/mL)d | Antimicrobial peptides against M. abscessus isolates, MIC value (μg/mL) |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CLA | AMK | |||||||||||
| Day 3 | Day 5 | Day 14 | Type of resistance | Day 5 | S61 | S62 | S63 | KLK1 | ||||
| MAB01 | M. abscessus | abscessus | Smooth | 1,024 (R) | 1,024 (R) | 1,024 (R) | Acquired | 64 (R) | 6.25 | 12.5 | 6.25 | 25 |
| MAB02 | M. abscessus | abscessus | Mixed | 1 (S) | 8 (R) | 64 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB03 | M. abscessus | abscessus | Smooth | 8 (R) | 8 (R) | 8 (R) | Acquired | 4 (S) | 6.25 | 12.5 | 12.5 | 50 |
| MAB04 | M. abscessus | abscessus | Mixed | 2 (S) | 16 (R) | 64 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB05 | M. abscessus | abscessus | Smooth | 4 (I) | 8 (R) | 16 (R) | Inducible | 32 (I) | >400 | >400 | >400 | >400 |
| MAB06 | M. abscessus | abscessus | Rough | 0.5 (S) | 2 (S) | 32 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB07 | M. abscessus | abscessus | Smooth | 4 (I) | 16 (R) | 16 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB08 | M. abscessus | abscessus | Rough | 1 (S) | 2 (S) | 8 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB09 | M. abscessus | abscessus | Mixed | 0.25 (S) | 8 (R) | 8 (R) | Inducible | 8 (S) | >400 | >400 | >400 | >400 |
| MAB10 | M. abscessus | abscessus | Smooth | 1,024 (R) | 1,024 (R) | 1,024 (R) | Acquired | 64 (R) | >400 | >400 | >400 | >400 |
| MAB11 | M. abscessus | abscessus | Mixed | 0.5 (S) | 16 (R) | 256 (R) | Inducible | 16 (S) | >400 | >400 | >400 | >400 |
| MAB12 | M. abscessus | massiliense | Rough | 1,024 (R) | 1,024 (R) | 1,024 (R) | Acquired | 8 (S) | >400 | >400 | >400 | >400 |
| MAB13 | M. abscessus | massiliense | Rough | 8 (R) | 32 (R) | 32 (R) | Acquired | 8 (S) | >400 | >400 | >400 | >400 |
| MAB14 | M. abscessus | massiliense | Rough | 512 (R) | 512 (R) | 512 (R) | Acquired | 64 (R) | >400 | >400 | >400 | >400 |
| MAB15 | M. abscessus | massiliense | Smooth | 4 (I) | 4 (I) | 4 (I) | Intermediate | 8 (S) | >400 | >400 | >400 | >400 |
| MAB16 | M. abscessus | massiliense | Mixed | 0.2 (S) | 2 (S) | 2 (S) | Susceptible | 32 (I) | >400 | >400 | >400 | >400 |
Note: AMP, antimicrobial peptide; MLST, multilocus sequence typing; CLA, Clarithromycin; AMK, Amikacin; DST, Drug susceptibility testing; S, susceptible; I, intermediate; R, resistant.
a Subspecies of M. abscessus were identified based on MLST as in a previous study [41].
b The DST was performed following the method that is described above and types of CLA resistance were interpreted based on in vitro MIC results.