TABLE 1.
Summary of performance for drug resistance determination using the MGIT960, MTBDRplus assay and whole genome sequencing.
| Isolate† phenotype | Isolates (n = 20) | Rifampicin |
Isoniazid |
Fluoroquinolone ofloxacin & moxifloxacin |
Aminoglycosidekanamycin & amikacin |
Pyrazinamide |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Phenotype | MTBDRplus | WGS | Phenotype | MTBDRplus | WGS | Phenotype | WGS | Phenotype | WGS | Phenotype | WGS | ||
| Concordant Susceptibility | 6 | S | S | S | S | S | S | S | S | S | S | S | S |
| Discordant in only 1 test | 1 | S | S | S | S‡ | inhAmut1 | InhAC-15T | S | S | S | S | S | S |
| Multidrug resistant | 5 | R | rpoBMut2a | rpoBH526Y | R | katGmut2/inhAmut1 | katGS315T/inhAc-15t | S | S | S | S | R | pncAH71Y |
| R | S§ | rpoBL511P | R | inhAmut3a | inhAt-8c | S | S | S | S | S | S | ||
| R | rpoBmut3 | rpoBS531L | R | inhAmut1 | inhAc-15t | S | S | S | S | S | S | ||
| R | rpoBmut2a | rpoBH526Y | R | inhAmut1 | inhAc-15t | S | S | S | S | S | S | ||
| R | rpoBmut3 | rpoBS531L | R | inhAmut1 | inhAc-15t | S | S | S | S | S | pncAT114M | ||
| Pre-extensively drug resistant | 1 | R | rpoBmut3 | rpoBS531L | R | katGmut2 | katGS315T | R | gyrAD94G | S | S | R | pncAC14R |
| Extensively drug resistant | 1 | R | rpoBWT2missing | rpoBH526L | R | katGmut3 | katGS315T | R | gyrAA90V | R | rrsa1401g | R | pncAdel373-387 |
| Discordant Pyrazinamide | 3 | S | S | S | S | S | S | S | S | S | S | S‡ | S |
| S | S | S | S | S | S | S | S | S | S | S‡ | S | ||
| S | S | S | S | S | S | S | S | S | S | S‡ | S | ||
| Discordant Fluoroquinolone | 3 | S | S | S | S | S | S | S‡ | S | S | S | S | S |
| S | S | S | S | S | S | ofloxacinR‡ | S | S | S | S | S | ||
| S | S | S | S | S | S | ofloxacinR‡ | S | S | S | S | S | ||
S, susceptible; R, resistant; MGIT, Mycobacterial Growth Indicator Tube; WGS, whole genome sequencing.
lower case represents nucleotide position change and uppercase amino acid position change (single abbreviation).
†
, Spoligotype profiles included – Beijing, Latin-American-Mediterranean (LAM), Central Asian Strain (CAS), East African-Indian (EAI) and East African-Indian – Somalian (EAI1).
‡
, Discordant result between initial and repeat testing.
§
, Incorrectly classified as susceptible by MTBDRplus assay.