TABLE 4.

Overall performance of the Reveal rapid AST system with blood cultures spiked with CDC & FDA AR bank isolates compared to CDC & FDA AR reference dataⁱ

Study details or performance parameter	Number and percentage
Study details	No. in 1st test	No. in 2nd test	No. in 1st and 2nd test
No. of species tested	6	6	6
No. of antibiotics testeda	14	14	14
No. of strains tested	10	10	20
No. of total strain-drug pairsb	122	122	244
No. of S strain-drug pairsc	11	11	22
No. of I/ATU strain-drug pairsc,d	3	3	6
No. of R strain-drug pairsc	108	108	216

^a The number of antibiotics varies depending on the respective species.

^b Of 123 strain-drug pairs, one MIC result for piperacillin-tazobactam and K. aerogenes was missing by the Reveal system, resulting in 122 evaluable strains-drug pairs.

^c The number of respective strain-drug pairs is the number based on CDC & FDA AR reference data. EUCAST clinical breakpoints were used for categorization.

^d CDC & FDA AR reference MIC of one K. aerogenes strain for ciprofloxacin was falling in the area of technical uncertainty (ATU) and was excluded for CA as well as for error calculation.

^e Because of the limited concentration ranges for most antibiotics on the test plate, MICs less or equal to the lowest concentration or greater than the highest concentration of a drug were included in the calculation.

^f Percentage (number) of strains for which the difference regarding all drugs tested was no more than ±1 log₂ dilution.

^g The concentration ranges of ciprofloxacin, ertapenem, and meropenem included skipped concentrations. If the Reveal system and/or CDC & FDA AR data showed a MIC above the highest skipped concentration, the respective strain was excluded from EA calculation. This was the case for one strain each in test one and two.

^h For meropenem and CDC & FDA AR MIC data, eight strains in each test had MIC values of >8 mg/L or >16 mg/L. On AST plates used in the study, the highest concentration is 32 mg/L for meropenem, resulting in MIC values of >32 mg/L if a strain grows at 32 mg/L. Thus, the eight strains were excluded from EA calculation.

ⁱ S, susceptible; I, susceptible increased dosage; R, resistant; EA, essential agreement; CA, category agreement; mE, minor error; ME, major error; VME, very major error.