TABLE 2.

MICs of tylosin for A. pyogenes strains, determined with and without induction

StrainAnimal species of isolationMIC (μg/ml)
TylosinTylosin after inductionaClindamycinEM
BBR1bBovine≤0.06NDc≤0.06≤0.06
01-4195Bovine>2,048>2,0485121,024
D9509363Bovine>2,048>2,0485121,024
JGS496Bovine>2,048>2,0485121,024
JGS573Bovine>2,048>2,0485121,024
JGS574Bovine>2,048>2,0485121,024
JGS597Porcine128128256256
JGS598Porcine128128256256
JGS599Porcine128128256256
OX-1Porcine128128256256
OX-7Porcine128128256256
JGS6000≤0.06>2,048
JGS6001≤0.06>2,048
  • a Induction involved 1 μg of tylosin per ml.

  • b BBR1 is a tylosin-susceptible strain whose results are shown for comparison.

  • c ND, not determined (as A. pyogenes strain BBR1 will not grow with 1 μg of tylosin/ml).