Current USCAST STIC
2025 USCAST Interpretive Tables
The 2025 edition of the USCAST STIC in a searchable PDF format can be downloaded.
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| A. baumannii | |||
|---|---|---|---|
| | Susceptible | Resistant | Doses and relevant notes |
| Ceftazidime | ≤ 32 | ≥ 64 | 2g every 8 hours |
| Ceftazidime-pneumonia | ≤ 8 | ≥ 16 | |
| Cefiderocol | IE | Currently available data do not support the usage of cefiderocol for A. baumannii infections | |
| Ciprofloxacin | ≤ 1 | ≥ 2 | 400 mg IV q8h |
| Minocycline | ≤ 0.5 / ≤ 1 | ≥ 1 / ≥ 2 | Susceptible breakpoints of ≤0.5 and ≤1 correspond to standard and high dose regimens of 100 mg q12h and 200 mg q12h, respectively. |
| Amikacin | ≤ 8 | ≥ 16 | 20 mg/kg IV q24 hours |
| Colistin (No breakpoints for respiratory tract infections) | ≤ 2 | ≥ 4 |
Polymyxin MIC determinations should be performed with broth microdilution. Colistin susceptibility can be used to infer polymyxin B susceptibility and vice versa. Colistin dosing based on EMA package insert or algorithm by Nation and colleagues*. Polymyxin B dosing 2.5 mg/kg/day Polymyxins should be combined with a second active agent whenever possible. |
| Polymyxin B (No breakpoints for respiratory tract infections or lower urinary tract infections) | ≤ 2 | ≥ 4 | |
| P. aeruginosa | ||||
|---|---|---|---|---|
| | Susceptible | Intermediate | Resistant | Doses and relevant notes |
| Cefepime | ≤ 8 | 16 | ≥ 32 | 1 g q8h or 2g q12h |
| Ceftazidime | ≤ 8 | 16 | ≥ 32 | 1 g q6h or 2g q8h |
| Cefiderocol | ≤ 4 | ≥ 8 | 2g q8h (3-hour infusion) | |
| Cefiderocol-pneumonia | ≤ 2 | ≥ 4 | ||
| Piperacillin-Tazobactam | ≤ 16/4 | ≥ 32/4 | 4.5g q6h (3-hour infusion) or 4.5g q8h (4-hour infusion) | |
| Aztreonam | ≤ 8 | 16 | ≥ 32 | 1 g q6h or 2g q8h |
| Ciprofloxacin | ≤ 0.5 | ≥ 1 | 400 mg IV q8h | |
| Levofloxacin | ≤ 1 | ≥ 2 | 750 mg q24h | |
| Colistin (No breakpoints for respiratory tract infections) | ≤ 2 | ≥ 4 |
Polymyxin MIC determinations should be performed with broth microdilution. Colistin susceptibility can be used to infer polymyxin B susceptibility and vice versa. Colistin dosing based on EMA package insert or algorithm by Nation and colleagues*. Polymyxin B dosing 2.5 mg/kg/day Polymyxins should be combined with a second active agent whenever possible |
|
| Polymyxin B (No breakpoints for respiratory tract infections or lower urinary tract infections) | ≤ 2 | ≥ 4 | ||
| | Susceptible | Susceptible-TDM2 | Resistant | |
| Gentamicin1 | ≤ 0.5 | 1 | ≥ 2 |
1STIC are based on the use of the extended interval aminoglycoside dosing recommendations provided in Table X. Trough monitoring is recommended for safety in all patients receiving aminoglycosides. 2The recommended doses are too low to reliably achieve PK/PD targets for efficacy (AUC/MIC ratio of approximately 80) for isolates with an MIC value in the S-TDM category. Therapeutic drug monitoring with dose adjustment as necessary to achieve both AUC/MIC and trough targets is required in this category, otherwise isolates with these MIC values should be considered resistant. |
| Tobramycin1 | ≤ 0.5 | 1 | ≥ 2 | |
| Amikacin1 | ≤ 2 | 4 | ≥ 8 | |
| Enterobacterales | ||||
|---|---|---|---|---|
| | Susceptible | Intermediate | Resistant | Doses and relevant notes |
| Cephalexin | No breakpoint recommended | The available evidence does not support the use of either cephalexin or oral cefuroxime for any systemic infection due to Enterobacterales. | ||
| Cefuroxime (oral) | No breakpoint recommended | |||
| Cefpodoxime | ≤ 1 | ≥ 2 | These STIC are based on high-dose cefpodoxime (400 mg every 12 hours) and a net bacterial stasis endpoint. Therefore, they should only be applied to non-severe, uncomplicated infections. | |
| Ceftriaxone | ≤ 1 | 2 | ≥ 4 | 1 g q24h |
| Cefotaxime | ≤ 1 | 2 | ≥ 4 | 1 g q8h |
| Ceftazidime | ≤ 4 | 8 | ≥ 16 | 1 g q8h |
| Cefiderocol | ≤ 4 | ≥ 8 | 2 g q8h (3-hour infusion) | |
| Cefiderocol — pneumonia | ≤ 2 | ≥ 4 | ||
| Piperacillin–Tazobactam | ||||
| AmpC Enterobacterales | No breakpoint recommended | This category consists of E. cloacae, K. aerogenes, and C. freundii. | ||
| 3GC-R Enterobacterales | No breakpoint recommended | 3GC stands for third-generation cephalosporin. | ||
| 3GC-S Enterobacterales | ≤ 16/4 | ≥ 32/4 | 4.5 g q6h (3-hour infusion) or 4.5 g q8h (4-hour infusion) | |
| Aztreonam | ≤ 4 | 8 | ≥ 16 | 1 g q8h |
| Ciprofloxacin | ≤ 0.25 | 0.5 | ≥ 1 | 400 mg IV q8h |
| Levofloxacin | ≤ 0.5 | 1 | ≥ 2 | 750 mg q24h |
| Moxifloxacin | ≤ 0.25 | ≥ 0.5 | 400 mg q24h | |
| Trimethoprim–Sulfamethoxazole | ≤ 4/76 | ≥ 8/152 | STIC are for uncomplicated urinary tract infection only and based on a dose of 1 double-strength tablet (160/800) q12h. | |
| Colistin (No breakpoints for respiratory tract infections) | ≤ 2 | ≥ 4 |
Polymyxin MIC determinations should be performed with broth microdilution. Colistin susceptibility can be used to infer polymyxin B susceptibility and vice versa. Colistin dosing based on EMA package insert or algorithm by Nation and colleagues*. Polymyxin B dosing 2.5 mg/kg/day. Polymyxins should be combined with a second active agent whenever possible. |
|
| Polymyxin B (No breakpoints for respiratory tract infections or lower urinary tract infections) | ≤ 2 | ≥ 4 | ||
| | Susceptible | Susceptible-TDM2 | Resistant | |
| Gentamicin1 | ≤ 0.5 | 1 | ≥ 2 |
1 STIC are based on the use of the extended-interval aminoglycoside dosing
(i.e., Tobramycin/Gentamicin 7 mg/kg q24h and Amikacin 20 mg/kg q24h). Trough monitoring is recommended
for safety in all patients receiving aminoglycosides. 2 The recommended doses are too low to reliably achieve PK/PD targets for efficacy (AUC/MIC ratio of approximately 80) for isolates with an MIC value in the S-TDM category. Therapeutic drug monitoring with dose adjustment as necessary to achieve both AUC/MIC and trough targets is required in this category; otherwise, isolates with these MIC values should be considered resistant. |
| Tobramycin1 | ≤ 0.5 | 1 | ≥ 2 | |
| Amikacin1 | ≤ 2 | 4 | ≥ 8 | |
*Nation RL, Garonzik SM, Thamlikitkul V, Giamarellos-Bourboulis EJ, Forrest A, Paterson DL, Li J, Silveira FP. Dosing guidance for intravenous colistin in critically-ill patients. Clin Infect Dis. 2017 Mar 1;64(5):565-571. doi: 10.1093/cid/ciw839. Epub 2016 Dec 23. PMID: 28011614; PMCID: PMC5850520.
Supporting rationale for the current STIC can be found here.