TABLE 3.

Discrepancies of the D-zone test versus the 4-μg/ml ERY-0.5-μg/ml CC combination wella

D-zone test resultOrganismStrainMIC (μg/ml)Discrepancy result at:Gene(s) detected
ERYCC18-h incubation in:24-h incubation in:
Medium 1Medium 2Medium 3Medium 1Medium 2Medium 3
PositiveS. aureusC-8380.12+++++ermA
S. aureusI-21>80.12+++ermA
S. aureusJ-50>80.25+++ermA, msrA
S. epidermidisC-20680.25++++ermC
NegativeS. aureusC-204>80.5++++++None
S. aureusJ-28>80.12++msrA
CoNSI-15>81+++ermA, msrA
  • a For D-zone test positive result, the discrepancy is no growth (−); for D-zone test negative result, the discrepancy is growth (+). Medium 1, BBL CAMHB; 2, Difco CAMHB; 3, Oxoid CAMHB. The macrolide resistance genes ermA, msrA, and ermC were detected by PCR.