Discrepant and indeterminate results of VITEK 2 tests compared to the results of the mecA PCR

IdentificationmecA PCR resultaOxacillin MIC (μg/ml)Susceptibility by oxacillin resistance testb
Initial testRetestInitial testRetest
S. kloosii≥8≥8RR
S. saprophyticus44SS
S. saprophyticus22SS
S. saprophyticus21SS
S. saprophyticus10.5SS
S. saprophyticus12SS
S. saprophyticus≤0.50.5SS
S. cohnii22SS
S. cohnii22SS
S. xylosus10.5SS
S. lugdunensis11SS
S. lugdunensis10.5SS
S. lugdunensis≤0.50.5SS
S. lugdunensis≤0.50.5SS
S. epidermidis22SS
S. epidermidis+12SS
S. hominis+≤0.50.5SS
S. haemolyticus+≤0.5≤0.25SS
S. saprophyticus+No growth≥8No growthR
S. saprophyticus+No growthNo growthNo growthNo growth
S. epidermidisNo growth≤0.5No growthS
  • a +, positive; −, negative.

  • b S, susceptible; R, resistant.