Table 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Descriptiona | β-Lactam resistance phenotype | Reference(s) |
|---|---|---|---|
| Strains | |||
| N315 | Japanese clinical pre-MRSA strain carrying a functional mecI encoding mecA gene repressor | Pre-MRSA | 11 |
| N315ΔIP | mecI null mutant derived from N315P, an N315-derivative strain with the penicillinase plasmid eliminated | Hetero-type | 12 |
| ΔIP-H5 | Mutant derived from N315ΔIP by selection with 8 mg/liter of imipenem, carrying rpoB(N967I) | Homo-type | 30 |
| ΔIP-H14 | Mutant derived from N315ΔIP by selection with 8 mg/liter of imipenem, carrying vraS(S329L) | Homo-type | 20, 30 |
| N315h4 | Mutant derived from N315 by selection with 128 mg/liter of methicillin | Eagle-type | 10 |
| H5 rpoB(I967N) | ΔIP-H5 in which rpoB(I967) is replaced by the wild-type rpoB | Hetero-type | This study |
| N315 rpoB(N967I) | N315 whose wild-type rpoB is replaced by rpoB(967I) mutation | Eagle-type | This study |
| Plasmids | |||
| pKOR1 | E. coli-S. aureus shuttle vector for construction of allelic replacement | 26 | |
| pKOR1-rpoB(967I) | pKOR1 harboring the 1,820-bp PCR product of mutated rpoB carrying amino acid residue Ile at position 967 | This study | |
| pKOR1-rpoB(967N) | pKOR1 harboring the 1,820-bp PCR product of wild-type rpoB carrying amino acid residue Asn at position 967 | This study |
a
Strains obtained by antibiotic selection are denoted as mutant.