TABLE 4

Derivation set resultsa

Antimicrobial agentNo. of isolates resistant by phenotypeNo. of isolates susceptible by phenotypeTotal no. of isolatesVery major error rate (%)Major error rate (%)Sensitivity (95% CI)Specificity (95% CI)
Susceptible by genotypeResistant by genotypeSusceptible by genotypeResistant by genotype
Penicillin44385905010.800.99 (0.98–1.00)1.00 (0.92–1.00)
Methicillin115834115010.20.20.99 (0.96–1.00)1.00 (0.98–1.00)
Ciprofloxacin716532635011.40.60.96 (0.91–0.98)0.99 (0.97–1.00)
Erythromycin113336615010.20.20.99 (0.95–1.00)1.00 (0.98–1.00)
Clindamycin088890177c001.00 (0.95–1.00)1.00 (0.95–1.00)
Tetracycline0284730501001.00 (0.85–1.00)1.00 (0.99–1.00)
Vancomycin00501050100N/Ad1.00 (0.99–1.00)
Fusidic acid3b3845825010.60.40.93 (0.79–0.98)1.00 (0.98–1.00)
Trimethoprim51030803231.500.67 (0.39–0.87)1.00 (0.98–1.00)
Gentamicin074940501001.00 (0.60–1.00)1.00 (0.99–1.00)
Mupirocin02174217801.11.00 (0.20–1.00)0.99 (0.96–1.00)
Rifampin1249805010.200.67 (0.13–0.98)1.00 (0.99–1.00)
Overall221,0694,08795,1870.20.40.98 (0.97–0.99)1.00 (0.99–1.00)
  • a Comparison of results for individual antimicrobial agents for 501 carriage/bacteremia isolates by phenotype (Vitek or disc diffusion) and predicted susceptibility using v2.0 genotypic prediction method. The result (resistant or susceptible) by phenotype refers to Vitek or disc diffusion results, and the result by genotype refers to the predicted susceptibility using the v2.0 genotypic prediction method.

  • b Two isolates had two nonsynonymous mutations in fusA not previously described in the literature (T326I plus E468V and T326I plus V90I) which may be responsible for the observed phenotypes.

  • c One isolate failed to grow for clindamycin testing.

  • d N/A, not applicable.