TABLE 3.

Characteristics of S. aureus wild-type and isogenic mutant strains isolated from spontaneous mutation frequency and serial passage experiments

Strain and antibiotic selectionIsolation experimenta23S rRNA mutation(s)bRibosomal protein mutation(s)cMIC (μg/ml)d
rRNA geneAllele(s)ProportionrplCL3rplDL4TR-700LZDTIACHLVAN
ATCC 29213 (MSSA)
    Wild type0.52181
    TR-700Serial pass.e0.52181
    LZDSpont. mut.G2447T41/60.54181
    LZDSerial pass.G2447T3, 42/618281
    LZDSerial pass.G2447T3, 42/5f216481
    LZDSerial pass.G2447T3, 4, 53/5f432881
    LZDSerial pass.G2447T3, 4, 53/5fG455AGly152Asp81283281
    LZDSerial pass.G2447T1, 3, 4, 54/5fG455AGly152Asp81286481
    TR-700, LZDSpont. mut.T2500A41/614181
    TR-700Spont. mut.T2500A4, 52/6282161
    LZDSerial pass.G463CGly155Arg14481
    TR-700, LZDSpont. mut.G463C/ A505TGly155Arg/ Met169Leu28442
    TR-700Spont. mut.ΔA384-A443ΔPhe127-His14628482
ATCC 33591 (MRSA)
    Wild type0.2510.5321
    LZDSerial pass.G2576T31/60.542641
    LZDSerial pass.G2576T3, 42/60.542641
    LZDSerial pass.G2576T3, 4, 53/61162641
    LZDSerial pass.G2576T2, 3, 4, 54/623241281
    TR-700Serial pass.T2571C/G2576T41/60.520.5321
    TR-700Serial pass.T2571C/G2576T4, 52/6141642
    TR-700Serial pass.T2571C/G2576T2, 4, 53/62161642
    LZDSerial pass.A202CLys68Gln0.521641
    TR-700, LZDSpont. mut.G463CGly155Arg0.524322
    TR-700Spont. mut.ΔA384-A443ΔPhe127-His146144322
  • a Representative strains derived from single colonies from serial passage (Serial pass.) and spontaneous mutation frequency (Spont. mut.) experiments are listed.

  • b The genetic basis of 23S rRNA mutations (rRNA gene, E. coli numbering), mutant 23S rRNA allele copy numbers [Allele(s)], and the proportion of the total number of 23S rRNA alleles detected that were mutant alleles are given.

  • c Ribosomal protein mutations (S. aureus numbering) are reported for the genes (rplC and rplD) and proteins (L3 and L4), respectively.

  • d MICs of TR-700, LZD, TIA, CHL, and VAN were determined for both strains.

  • e TR-700 serial passage no. 30 ATCC 29213 is included for reference, although no mutations or MIC increases were observed.

  • f 23S rRNA gene copy 6 (rrn6) was not detected by PCR in this strain.