Table 2.
Performance of the Accelerate Pheno™ system and VITEK® 2 systems compared with BMD for Gram-positive bacterial species (n = 24)
| BMD |
Accelerate Pheno™ system [% (n/N)] |
VITEK® 2 system [% (n/N)] |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Antimicrobial | n | S | I | R | categorical agreementa | errors |
categorical agreementa | errors |
||||
| VMEs | MEs | mEs | VMEs | MEs | mEs | |||||||
| S. aureus | 10 | |||||||||||
| erythromycin | 7 | 0 | 3 | 100 (10/10) | 0.0 (0/3) | 0.0 (0/7) | 0.0 (0/10) | 100 (10/10) | 0.0 (0/3) | 0.0 (0/7) | 0.0 (0/10) | |
| SXT | 10 | 0 | 0 | 90.0 (9/10) | NA (0/0) | 0.0 (0/10) | 10.0 (1/10) | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | |
| daptomycin | 10 | 0 | 0 | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | |
| linezolid | 10 | 0 | 0 | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | |
| vancomycin | 10 | 0 | 0 | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | 100 (10/10) | NA (0/0) | 0.0 (0/10) | 0.0 (0/10) | |
| CoNS | 6 | |||||||||||
| erythromycin | 1 | 0 | 5 | 100 (5/5) | 0.0 (0/4) | 0.0 (0/1) | 0.0 (0/5) | 100 (6/6) | 0.0 (0/5) | 0.0 (0/1) | 0.0 (0/6) | |
| daptomycin | 6 | 0 | 0 | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | |
| linezolid | 6 | 0 | 0 | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | |
| vancomycin | 6 | 0 | 0 | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | 100 (6/6) | NA (0/0) | 0.0 (0/6) | 0.0 (0/6) | |
| E. faecalis | 5 | |||||||||||
| ampicillin | 5 | 0 | 0 | 100 (5/5) | NA (0/0) | 0.0 (0/5) | 0.0 (0/5) | 100 (5/5) | NA (0/0) | 0.0 (0/5) | 0.0 (0/5) | |
| linezolid | 5 | 0 | 0 | 100 (5/5) | NA (0/0) | 0.0 (0/5) | 0.0 (0/5) | 100 (5/5) | NA (0/0) | 0.0 (0/5) | 0.0 (0/5) | |
| vancomycin | 4 | 0 | 1 | 100 (4/4) | NA (0/0) | 0.0 (0/4) | 0.0 (0/4) | 80.0 (4/5) | 100 (1/1) | 0.0 (0/4) | 0.0 (0/5) | |
| Enterococcus faecium | 3 | |||||||||||
| ampicillin | 0 | 0 | 3 | 100 (3/3) | 0.0 (0/3) | NA (0/0) | 0.0 (0/3) | 100 (3/3) | 0.0 (0/3) | NA (0/0) | 0.0 (0/3) | |
| linezolid | 3 | 0 | 0 | 100 (3/3) | NA (0/0) | 0.0 (0/3) | 0.0 (0/3) | 100 (3/3) | NA (0/0) | 0.0 (0/3) | 0.0 (0/3) | |
| vancomycin | 1 | 0 | 2 | 100 (3/3) | 0.0 (0/2) | 0.0 (0/1) | 0.0 (0/3) | 100 (3/3) | 0.0 (0/2) | 0.0 (0/1) | 0.0 (0/3) | |
| Total | 24 | 84 | 0 | 14 | 99.0 (95/96) | 0.0 (0/12) | 0.0 (0/84) | 1.0 (1/96) | 99.0 (97/98) | 7.1 (1/14) | 0.0 (0/84) | 0.0 (0/98) |
NA, not applicable; S, susceptible; I, intermediate; R, resistant. SXT, trimethoprim/sulfamethoxazole.
a
Values in parentheses are the numbers of results with same categorical interpretation as the reference BMD results over the total numbers of test results. The Accelerate Pheno™ system did not provide AST results for the following antibiotic-pathogen combinations: erythromycin/coagulase-negative Staphylococcus sp. (n = 1) and vancomycin/E. faecalis (n = 1).