TABLE 3.

Characteristics of isolates categorized by disk diffusion induction test phenotype

ParameterDisk diffusion phenotype
DD+NegHDRS
No. of isolates211710331631
Disk zone mode (range) in mm
    ERY7 (6-8)6 (6-7)6 (6-10)6 (6)6 (6)25 (20-28)
    CLI25 (22-30)25 (23-30)24 (23-31)6 (6)6 (6)24 (23-31)
BMD MIC50 (range) in μg/ml
    ERY>128 (8->128)>128 (>128)128 (8-128)>128 (>128)>128 (>128)0.5 (0.5-1)
    CLI0.25 (0.12-0.25)0.25 (0.12-0.25)0.12 (0.12-0.25)>64 (>64)>64 (>64)0.12 (0.12-0.25)
No. of isolates that grew in medium
    CLI, 8 μg/ml, plus
        ERY, 0.12 μg/ml017033160
        ERY, 0.06 μg/ml016033160
        ERY, 0.03 μg/ml04033160
    CLI, 4 μg/ml, plus
        ERY, 0.12 μg/ml017033160
        ERY, 0.06 μg/ml016033160
        ERY, 0.03 μg/ml07033160
    CLI, 2 μg/ml, plus
        ERY, 0.12 μg/ml017033160
        ERY, 0.06 μg/ml017033160
        ERY, 0.03 μg/ml015033160
    CLI, 1 μg/ml, plus
        ERY, 4 μg/ml2017033160
        ERY, 1 μg/ml1717033160
    CLI, 0.5 μg/ml, plus ERY, 1 μg/ml21a17033160
PCR result (no. of isolates) ermA (21) ermC (16), ermC + ermA (1) msrA (10) ermA (31), ermA + msrA (1), ermC (1) ermA (8), ermA + ermC (3), ermA + msrA (1), ermB (1), ermC (3)
Oxacillin interpretation (no. of isolates)S (5), R (16)S (8), R (9)S (2), R (8)S (2), R (31)S (3), R (13)S (18), Ib & R (13)
  • a One isolate was not detected as inducible on repeat testing.

  • b I, intermediate.