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Table 1 Description of results, time and cost of microbiological analysis during two phases of the investigation of two cases of glycopeptide-resistant Enterococci

From: Rapid detection of glycopeptide-resistant enterococci: impact on decision-making and costs

  Investigation of the first case in the diabetology unit Investigation of a secondary case in the nephrology unit
  (n=31 patients) (n=22 patients)
Test Results, n (%)   
Cepheid Xpert™ van A/van B assay:   
Negative PCR 1 (3)a 17 (77)
Positive van A 1 (3)a 0 (0)
Positive van B and culture showing susceptible strain - 2 (9)
PCR invalid then negative culture - 2 (9)
PCR invalid then culture showing susceptible stain - 1 (5)
Culture after enrichment using chromogenic medium:   
Negative culture 26 (84) -
Culture positive for GRE strainb 1 (3)a -
Culture positive for susceptible Enterococcusc 4 (13) -
Turn-around time (hours, median [Q1-Q3])   
From sampling, to sample reception 2.6 (1.7-2.6) 2.8 (1.1 – 3.8)
From sample reception, to inoculation or preparation 2.3 (2.2– 2.4) 1.3 (0.5 – 2.3)
From inoculation or preparation, to results 65.5 (65.5– 65.5) 1 (0.9-1.1)
From sample reception, to results 67.8 (68.4 – 67.9) 6.22 (3.7 – 8.2)
From sampling, to results 70.5 (69.4 – 70.5) 4.6 (4.0 – 18.9)
Maximal time to obtain all results 70.5 90.0
Cost of microbiological analysis (€)   
Cepheid Xpert™ van A/van B assay:   
Cost of 1 cartridge - 35.60
Cost of 1 test - 37.30
Culture with chromogenic medium and enrichment   
Cost of a negative culture 4.80 -
Cost of a doubtful culturec 13.40 -
Cost of a doubtful cultured 23.50 -
Cost of a positive cultureb 117.80 -
Total cost of microbiological testing 333.50 870.40
Loss of income   
Cost per weighted case per day in 2011e 340.70 426.00
Scenario 1: Implementation of local guidelines   
    Patient-days lost f 41 0
    Estimated loss of income (€) 13,968.70 0
Scenario 2: Implementation of national guidelines   
    Patient-days lostf 250 0
    Estimated loss of income (€) 85,175.00 0
Overall loss of income (€) 13,968.70 to 85,175.00 0
Overall cost of the strategy (€) 14,302.20 to 86,175.50g 870.40 to 2,611.20g
  1. PCR, polymerase chain reaction; GRE, Glycopeptide-Resistant Enterococci ; Q1, First quartile; Q3, Third quartile.
  2. aReal-time PCR assay performed on an exceptional basis to screen the two patients who shared the room of the first patient in the diabetology ward.
  3. bPositive culture with identification of E. faecium by mass spectrometry assay, MICs >8 mg/L for vancomycin and/or teicoplanin on E-test strips, antibiotic susceptibility testing by disk diffusion in solid media for clinical purpose, and detection of the vancomycin resistance genotype by DNA strip assay.
  4. cPositive culture with identification of Enterococcus faecium by mass spectrometry assay with MICs ≤8 mg/L for vancomycin and/or teicoplanin on E-test strips.
  5. dPositive culture with identification of E. faecium by mass spectrometry assay, MICs >8 mg/L for vancomycin and/or teicoplanin on E-test strips, and antibiotic susceptibility testing by disk diffusion in solid media for clinical purpose.
  6. eEstimated costs of inpatient care based on reimbursement rates of the diagnosis-related group. In France, the diagnosis-related group price is calculated by multiplying standard amounts for operating and capital expenses found in yearly surveys by a national “weight” associated with the DRG for each hospitalisation. The weighting takes in account variations due to geographic area and atypical observations.
  7. fNumber of missed patient-days due to the interruption of patients’ transfers and admissions.
  8. gCosts estimation assuming the strict implementation of French national guidelines with three weekly screening of patients.