TABLE 2.
Accuracy of 11 phenotypic assays for carbapenemase detection, including 67 carbapenem-resistant Pseudomonas aeruginosa isolates and 24 carbapenem-resistant Acinetobacter baumannii isolates
| Assay | % sensitivity (95% confidence interval) |
% specificity (95% confidence interval) |
||
|---|---|---|---|---|
| Carbapenemase-producing Pseudomonas aeruginosaa (n = 14) | Carbapenemase-producing Acinetobacter baumaniib (n = 14) | Non-carbapenemase-producing Pseudomonas aeruginosa (n = 53) | Non-carbapenemase-producing Acinetobacter baumannii (n = 10) | |
| Rapidec Carba NP | 100 (73–100) | 86 (56–97) | 91 (76–96) | 70 (35–92) |
| Neo-Rapid Carb Screen | 100 (73–100) | 86 (56–97) | 98 (89–100) | 100 (66–100) |
| Rapid CARB Blue Screen | 100 (73–100) | 57 (30–81) | 98 (89–100) | 100 (60–100) |
| Manual Carba NP CLSI | 93 (64–100) | 21 (6–51) | 100 (92–100) | 100 (60–100) |
| Manual Blue Carba | 100 (73–100) | 57 (30–81) | 77 (63–87) | 90 (54–99) |
| Modified Carba NP | 100 (73–100) | 79 (49–94) | 60 (46–73) | 80 (44–96) |
| Boronic acid synergy test | 50 (3–97) | 57 (44–69) | 96 (76–100) | |
| Metallo-β-lactamase Etest | 75 (43–93) | 80 (30–99) | 84 (71–92) | 94 (71–100) |
| Modified Hodge test | 64 (36–86) | 71 (42–90) | 98 (89–100) | 70 (35–92) |
| Carbapenem inactivation method | 79 (49–94) | 29 (10–58) | 100 (92–100) | 80 (44–96) |
| Modified carbapenem inactivation method | 100 (73–100) | 71 (42–90) | 98 (89–100) | 70 (35–92) |
a
The carbapenemases harbored by the P. aeruginosa isolates were as follows: KPC (n = 2); VIM (n = 8); IMP (n = 3); SPM (n = 1).
b
The carbapenemases harbored by the A. baumannii isolates were as follows: NDM (n = 4); NDM and OXA-23 (n = 1); OXA-23 (n = 3); OXA-24 (n = 3); OXA-58 (n = 1); OXA-72 (n = 1); OXA-23 and OXA-24 (n = 1).