Table 1.

Strains and plasmids used in this study

StrainsRelevant characteristicsSource or reference
Strain
S. aureus
  RN4220Mcsrestriction negativeR. Novick
  M100Mcrlaboratory step mutant30
  27sMcs30
  COLHomogeneous Mcr, MIC of 1,600 μg ml−1Rockefeller University collection
  M100R130M100 (pbp2::Tn551) EmrThis study
  RUSA 130COL Ω703 (pbp2::Tn551) Emrheterogenous, MIC of 12 μg ml−16, 23, 24
  RN4220pPBP3-B3RN4220/pPBP3B inserted into the chromosome Mcs EmrThis study
  M100pPBP3-AM100/pPBP3A inserted into the chromosome Mcr EmrThis study
  COLpPBP3-B1COL/pPBP3B inserted into the chromosome Mcr EmrThis study
  COLpPBP3-B4COL/pPBP3B inserted into the chromosome Mcr EmrThis study
E. coli DH5αrecA endA1 gyrA96 thi-1 hsdR17 supE44 relA1 φ80 ΔlacZΔM15Bethesda Research Laboratories
Plasmids
 pSP64E. coliplasmid, AmprPromega
 pSP64EPSP64/1.2 kb witherm gene from Tn551This study
 pPBP3ApSP64E/2.0 kb encoding aa 61–691 of PBP 3This study
 pPBP3BpSP64E/1.4 kb encoding aa 61–544 of PBP 3This study