Table 1.
Observed MIC for RFB and RIF and associated rpoB mutations
| Amino acid change (nucleotide changes) |
Observed MIC (µg/ml) | |
|---|---|---|
| RIF MIC (Isolates tested) |
RFB MIC (Isolates tested) |
|
| Group I, RIF-S and RFB-S | ||
| Wildtype | ≤ 0.125 (2), 0.125 (2) | ≤ 0.0625 (37), 0.125 (5) |
| L511P(CCG) | ≤ 0.25 (2), 0.25 (1) | ≤ 0.0625 (2), 0.0625 (1) |
| F514F(TTT) | 0.125 (2) | ≤ 0.0625 (2) |
| D516Y(TAC) | 0.25 (2), 0.5 (2) | 0.0625 (4) |
| H526N(AAC) | 0.125 (2), 0.25 (1) | ≤ 0.0625 (2), 0.125 (1) |
| H526S(AGC) | 0.5 (1), 1 (1) | ≤ 0.0625 (1), 0.125 (1) |
| H526S(TCC) | 0.25 (1) | ≤ 0.0625 (1) |
| S531C(TGT) | ≤ 0.125 (1) | 0.0625 (1) |
| L533P(CCG) | 0.5 (2) | 0.125 (1), 0.25 (1) |
| T508 to S509 deletion | 0.5 (1) | ≤ 0.0625 (1) |
| M515I(ATA) + H526N(AAC) | 1 (1) | 0.125 (1) |
| Group II, RIF-R and RFB-S | ||
| D516V(GTC) | 8 (3), > 8 (15) | 0.125 (2), 0.25 (6), 0.5 (10) |
| D516F(TTC) | 2 (1) | 0.0625 (1) |
| S522L (TTG) | 2 (1) | 0.0625 (1) |
| H526A(GCC) | 2 (1) | 0.125 (1) |
| H526C(TGC) | 2 (1), 8 (1) | 0.125 (2) |
| H526G(GGC) | 2 (1) | 0.125 (1) |
| H526L(CTC) | 2 (2), 4 (1), 8 (1) | 0.125 (2), 0.25 (1), 0.5 (1) |
| N518 deletion | 4 (1) | 0.125 (1) |
| S522L(TTG) + K527R(AGG) | 8 (1) | 0.5 (1) |
| H526S(TCC) + K527R(CGG) | 4 (1) | 0.25 (1) |
| Group III, RIF-R AND RFB-R | ||
| Q513E(GAA) | > 8 (2) | 1 (2) |
| Q513K(AAA) | > 8 (3) | > 8 (3) |
| Q513L(CTA) | > 8 (1) | > 8 (1) |
| Q513P(CCA) | > 8 (2) | 1 (1), 2 (1) |
| H526D(GAC) | > 8 (3) | 8 (2), > 8 (1) |
| G526R(CGC) | > 8 (2)a | 8 (2), > 8 (3) |
| H526Y(TAC) | > 8 (1)a | 8 (2), > 8 (2) |
| S531F(TTC) | > 8 (1) | > 8 (1) |
| S531W(TGG) | > 8 (3)a | 4 (1), 8 (2), >8 (1) |
| S531L(TTG) | > 8 (5)a | 2 (7), 4 (25), 8 (1) |
| S509R(CGC) + H526Y(TAC) | > 8 (1) | 8 (1) |
| S509R(AGG) + H526L(CTC) | > 8 (1) | 8 (1) |
| Q510L(CTG) + D516V(GTC) | > 8 (1) | 1 (1) |
| L511P(CCG) + S512T(ACC) + D516Y(TAC) | > 8 (1) | 8 (1) |
| L511P(CCG + D516Y(TAC) | > 8 (2) | 2 (2) |
| Q513L(CTA) + H526N(AAC) | > 8 (1) | > 8 (1) |
| F514F(TTT) + S531L(TTG) | > 8 (1) | 8 (1) |
| 515 to 521 deletion | > 8 (1) | 8 (1) |
| D516E(GAG) + S522L(TTG) | > 8 (1) | 1 (1) |
| D516V(GTC) + S531L(TTG) | > 8 (1) | 4 (1) |
| D516G(GGC) + L533P(CCG) | > 8 (1) | 4 (1) |
| H526Q(CAG) + L533P(CCG) | > 8 (1) | 1 (1) |
a
These mutations are commonly found in isolates from MDR TB patients and they are known to confer high level resistance to RIF; RIF MIC was performed for limited numbers of those strains. RFB MIC was performed for all strains included in this study.