Table 2. Laboratory detection and molecular characteristics of MTB isolated from a XDR-TB patient (case 1) and a pre-XDR-TB patient (case 2) on theThailand-Myanmar border.
| Laboratory testing | Patient 1 (XDR-TB) |
Patient
2 (Pre-XDR-TB) |
||
|---|---|---|---|---|
| AFB | Positive | Positive | ||
| LAMP | MTB | MTB | ||
| Xpert MTB/RIF | MTB | MTB | ||
| Culture | MTB | MTB | ||
| Results of DST | Xpert MTB/RIF | Rifampicin | R | S |
| LPA 1st line (MTBDRplus) |
Rifampicin (rpoB) | R | S | |
| Isoniazid (katG/inhA) | R | R | ||
| LPA 2nd line (MTBDRsl) |
Fluoroquinolones (gyrA) | R | R | |
| AG / CP (rrs) | R | S | ||
| Solid
DST 1st line (µg/mL) |
Rifampicin (40.0) | R | R | |
| Isoniazid (0.2/1.0) | R | R | ||
| Streptomycin (4.0) | R | S | ||
| Ethambutol (2.0) | R | S | ||
| Solid
DST 2nd line (µg/mL) |
Ofloxacin (2.0) | R | R | |
| Kanamycin (30.0) | R | S | ||
| Levofloxacin (2.0) | R | R | ||
| Cycloserine (40.0) | S | S | ||
| PAS (1.0) | R | S | ||
| Capreomycin (40.0) | R | S | ||
| DNA
sequencing 1st line |
rpoB | Ser531Leu (TCG→TTG) |
Wild-type | |
| katG | Ser315Thr (AGC→ACC) |
Ser315Thr (AGC→ACC) |
||
| DNA
sequencing 2nd line |
gyrA | Asp94Gly (GAC→GGC) |
Asp94Tyr (GAC→TAC) |
|
| rrs | A1401G | Wild-type | ||
| Genotyping | Spoligotyping | Spoligotype | Beijing | T2 |
| SIT no. | 941 | 52 | ||
| MIRU-VNTR typing* | 4 4 2 3 3 3 5 4 3 4 5 5 3 8 2 3 | 3 4 2 2 3 3 3 1 2 4 1 3 5 8 3 2 |
*
Genetic markers located in 16 loci, in order: VN424 (424), ETR-C (577), MIRU04 (580), MIRU40 (802), MIRU10 (960), MIRU16 (1644), VN1955 (1955), QUB11b (2163b), ETR-A (2165), VN2401 (2401), MIRU26 (2996), MIRU31 (3192), VN3690 (3690), QUB26 (VN4052), VN4156 (4156) and MIRU39 (4348); AFB = acid-fast bacilli; LAMP = loop-mediated isothermal amplification; MTB = Mycobacterium tuberculosis; DST = drug susceptibility testing; LPA = line probe assay; AG/CP = aminoglycosides/cyclic peptides; PAS = para-aminosalicylic acid; MIRU-VNTR = mycobacterial interspersed repetitive unit-variable number tandem repeat; R = resistant; S = susceptible.