Table 1 AST results of the Alfred 60AST™ system compared to BD Phoenix™ system for each antibiotic. Column 2 shows the total number of susceptibility tests done with both methods; columns 3 to 6 the total number of tests for which there was agreement within each category and in total; columns 8 to 10 the number of discrepancies; S = susceptible = intermediate, R = resistant, CA = Categorical agreement, 95% CI = 95% confidence interval
No. of category agreements | No. of discrepancies | ||||||||
|---|---|---|---|---|---|---|---|---|---|
Antimicrobial agent | No. of AST results | S | R | I | CA Total | CA % (95% CI) | Minor | Major | Very major |
Gram-negative antimicrobials | |||||||||
Ampicillin | 301 | 88 | 202 | 0 | 290 | 96 (94–98) | 0 | 4 | 7 |
Amikacin | 298 | 273 | 2 | 2 | 277 | 93 (89–96) | 3 | 17 | 1 |
Ciprofloxacin | 297 | 222 | 61 | 0 | 283 | 95 (92–97) | 1 | 7 | 6 |
Ceftriaxone | 78 | 64 | 11 | 0 | 75 | 96 (89–99) | 0 | 1 | 2 |
Gentamicin | 297 | 240 | 38 | 1 | 279 | 94 (91–96) | 1 | 10 | 7 |
Piperacillin/Tazobactam | 295 | 263 | 16 | 1 | 280 | 95 (92–97) | 0 | 10 | 5 |
Meropenem | 297 | 284 | 4 | 0 | 288 | 97 (94–99) | 0 | 6 | 3 |
Overall agreement | 1863 | 1434 | 334 | 4 | 1772 | 95 (94–96) | 5 (0.3%) | 55 (3%) | 31 (2%) |
Gram-positive antimicrobials | |||||||||
Cefoxitin | 75 | 34 | 35 | 0 | 69 | 92 (83–97) | 0 | 4 | 2 |
Cindamycin | 75 | 41 | 17 | 2 | 60 | 80 (69–88) | 1 | 9 | 5 |
Teicoplanin | 86 | 79 | 0 | 1 | 79 | 92 (84–97) | 1 | 6 | 0 |
Vancomycin | 86 | 76 | 1 | 0 | 77 | 90 (81–95) | 0 | 9 | 0 |
Ampicillin | 11 | 9 | 1 | 0 | 10 | 90 (59–100) | 0 | 1 | 0 |
Overall agreement | 333 | 239 | 54 | 3 | 295 | 89 (85–92) | 2 (0.6%) | 29 (9%) | 7 (2%) |