Table 1.

Comparison of the MRSA-Screen test and two phenotypic tests to classify 200 S. aureus clinical isolates as MRSA or MSSAa

Test methodMRSA (mecA gene positive) (n = 80)MSSA (mecA gene negative) (n = 120)Sensitivity (%)Specificity (%)
True positiveFalse negativeIndeterminateTrue negativeFalse positive
MRSA-Screen80001191b 10099.2
Oxacillin disk diffusion492011116461.396.7
Oxacillin-salt agar screen66140118282.598.3
  • a Defined by the presence or absence, respectively, of the mecA gene.

  • b This isolate, when retested, gave no agglutination.