TABLE 3.

Antibiotic resistance of E. faecalis response regulator mutantsc

StrainAmpaAmpbBacaCefaCxmaCtxaCamaCambCipaCliaErybGenbImiaNalaNitaNovaRifaVanaVanb
V583T274141466188206>1,000>2,0002462016168128
RR01264 19 1466188206>1,000>2,0002462117168128
RR02274131466188196>1,000>2,0002362017168128
RR03264 19 1466188196>1,000>2,0002462116178128
RR04264141466188206>1,000>2,0002462016168128
RR05274 17 14 14 16 188206>1,000>2,000246201616 13 32
RR06264141466188196>1,000>2,0002462016168128
RR08264131466188206>1,000>2,0002462016168128
RR09264141466188196>1,000>2,0002462016178128
RR10264141466188206>1,000>2,0002462016168128
RR11264141466188206>1,000>2,000246211616 17 <2
RR12264141466188206>1,000>2,0002462017178128
RR13264141466188206>1,000>2,0002462116168128
RR14264141466188206>1,000>2,0002462117178128
RR15264141466188206>1,000>2,0002362016168128
RR16264141466188196>1,000>2,0002362116168128
RR17264141466188196>1,000>2,0002462117168128
RR18264141466188206>1,000>2,0002362116168128
  • a Determined by the disk diffusion method. The values reported are the diameters of the zones of inhibition in millimeters. The diameter of each disk is 6 mm, and for some antibiotics no inhibition zone was observed.

  • b Determined by the microtiter twofold serial dilution method. The values reported are the MICs in micrograms per milliliter.

  • c Antibiotic resistance abbreviated as follows: Amp, ampicillin; Bac, bacitracin; Cef, cephalothin (first-generation cephalosporin); Cxm, cefuroxime (second-generation cephalosporin); Ctx, cefotaxime (third-generation cephalosporin); Cam, chloramphenicol; Cip, ciprofloxacin; Cli, clindamycin; Ery, erythromycin; Gen, gentamicin; Imi, imipenem; Nal, nalidixic acid; Nit, nitrofurantoin; Nov, novobiocin; Rif, rifampin; Van, vancomycin. Boldface values indicate significant differences between mutants and the parental strain.