Table 4.
Use of Current Breakpoint by Laboratory Location and Automated Antimicrobial Susceptibility Testing System
| Organism | Agent | System | United Statesa | Internationalb | ||
|---|---|---|---|---|---|---|
| Total No. of Laboratories | Current Breakpoint, No. (%) | Total No. of Laboratories | Current Breakpoint, No. (%) | |||
| Enterobacterales | Ceftazidime | Phoenix | 63 | 49 (77.8) | 36 | 30 (83.3) |
| MicroScan | 347 | 182 (52.4) | 19 | 15 (78.9) | ||
| Vitek 2 | 572 | 354 (61.9) | 122 | 102 (83.6) | ||
| Enterobacterales | Ceftriaxone | Phoenix | 70 | 62 (88.6) | 37 | 34 (91.9) |
| MicroScan | 360 | 214 (59.4) | 14 | 10 (71.4) | ||
| Vitek 2 | 638 | 391 (61.3) | 111 | 91 (82.0) | ||
| Enterobacterales | Ciprofloxacin | Phoenix | 63 | 22 (34.9) | 35 | 23 (65.7) |
| MicroScan | 332 | 50 (15.1) | 19 | 9 (47.4) | ||
| Vitek 2 | 579 | 204 (35.2) | 127 | 80 (63.0) | ||
| Enterobacterales | Levofloxacin | Phoenix | 63 | 23 (36.5) | 33 | 20 (60.6) |
| MicroScan | 307 | 51 (16.6) | 18 | 10 (55.6) | ||
| Vitek 2 | 555 | 195 (35.1) | 81 | 45 (55.6) | ||
| Enterobacterales | Meropenem | Phoenix | 65 | 57 (87.7) | 36 | 33 (91.7) |
| MicroScan | 322 | 180 (55.9) | 19 | 16 (84.2) | ||
| Vitek 2 | 507 | 321 (63.3) | 107 | 82 (76.6) | ||
| Pseudomonas aeruginosa | Piperacillin-/tazobactam | Phoenix | 65 | 55 (84.6) | 35 | 31 (88.6) |
| MicroScan | 353 | 189 (53.5) | 19 | 14 (73.7) | ||
| Vitek 2 | 553 | 266 (48.1) | 113 | 86 (76.1) | ||
| Acinetobacter baumannii | Imipenem | Phoenix | 49 | 38 (77.6) | 33 | 29 (87.9) |
| MicroScan | 258 | 115 (44.6) | 17 | 12 (70.6) | ||
| Vitek 2 | 381 | 161 (42.3) | 101 | 79 (78.2) | ||
Significant system differences for US laboratories:
Ceftazidime: Phoenix – MicroScan, P = .003; MicroScan – Vitek 2, P = .04.
Ceftriaxone: Phoenix – MicroScan, P < .001; Phoenix – Vitek 2, P < .001.
Ciprofloxacin: Phoenix – MicroScan, P = .003; MicroScan – Vitek 2, P < .001.
Levofloxacin: Phoenix – MicroScan, P = .004; MicroScan – Vitek 2, P < .001.
Meropenem: Phoenix – MicroScan, P < .001; Phoenix – Vitek 2, P = .002.
Piperacillin-tazobactam: Phoenix – MicroScan, P < .001; Phoenix – Vitek 2, P < .001.
Imipenem: Phoenix – MicroScan, P < .001; Phoenix – Vitek 2, P < .001.
Significant system differences between US and international laboratories:
Ceftazidime: Vitek 2, P < .001.
Ceftriaxone: Vitek 2, P < .001.
Ciprofloxacin: Phoenix, P = .04; MicroScan, P < .001; Vitek 2, P < .001.
Levofloxacin: MicroScan, P = .002; Vitek 2, P = .005.
Piperacillin-tazobactam: Vitek 2, P < .001.
Imipenem: Vitek 2, P < .001.