Table 2.
Results of rifampicin susceptibility testing and rpoB genotyping
| Clonal type1 (clonal complex) | PFGE cluster2 (n)/spa type (n) | Isolate origin (isolate name) | Rifampicin MIC (mg/L)3 | Amino acid position4 | Nucleotide substitution | Amino acid substitution |
|---|---|---|---|---|---|---|
| ST22- MRSA-IV (22) | Sporadic isolate (1)/t032 (1) | Cape Town, RSA5 | ≤ 0.016 | 498 | GCG → GCT | - |
| 554 | CAT → CAC | - | ||||
| 599 | AAT → AAC | - | ||||
| ST36- MRSA-II (30) | F (1)/t021 (1) | Cape Town, RSA | ≤ 0.016 | 474 | AAC → AAT | - |
| 498 | GCG → GCT | - | ||||
| 502 | GTA → GTG | - | ||||
| 518 | ACA → ACG | - | ||||
| ST5- MRSA-I (5) | C (1)/t045 (1) | Cape Town, RSA | ≥ 256 | 481 | CAT → TAT | H481Y |
| 498 | GCG → GCT | - | ||||
| 630 | AAT → AAC | - | ||||
| 658 | GGT → GGA | - | ||||
| ST612- MRSA-IV (8) | D (2), E (5), sporadic isolates (2)/t064 (3), t1443 (5), t1257 (1) | Cape Town, RSA | ≥ 256 | 481 | CAT → AAT | H481N |
| 498 | GCG → GCT | - | ||||
| 512 | CGT → CGC | - | ||||
| 527 | ATT → ATG | I527M | ||||
| ST612- MRSA-IV (8) | ND6 (2)/t064 (2) | RSA (N83; N84) | ≥ 256 | 481 | CAT → AAT | H481N |
| 498 | GCG → GCT | - | ||||
| 512 | CGT → CGC | - | ||||
| 527 | ATT → ATG | I527M | ||||
| ST612- MRSA-IV (8) | ND (1)/t064 (1) | Australia (04-17052) | ≥ 256 | 481 | CAT → AAT | H481N |
| 498 | GCG → GCT | - | ||||
| 512 | CGT → CGC | - | ||||
| 527 | ATT → ATG | I527M | ||||
| ST612- MRSA-IV (8) | ND (1)/t7571 (1) | Australia (09-15534) | ≥ 256 | 481 | CAT → AAT | H481N |
| 498 | GCG → GCT | - | ||||
| 512 | CGT → CGC | - | ||||
| 527 | ATT→ATG | I527M | ||||
| 579 | AAA→AGA | K579R | ||||
1 Clonal types are indicated using the current international nomenclature (sequence type (ST) - antimicrobial phenotype - staphylococcal cassette chromosome mec (SCCmec) type)
2 PFGE, pulsed-field gel electrophoresis
3 As determined by E-test
4 S. aureus co-ordinates
5 RSA, Republic of South Africa
6 ND, not determined