Although multiple antimicrobial resistance (AMR) determinants can confer the same in vitro antimicrobial susceptibility testing (AST) phenotype, their differing effect on optimal therapeutic choices is uncertain. Using a large population-based collection of clinical strains spanning a 3.5-year period, we applied WGS to detect inhibitor resistant (IR), extended-spectrum β-lactamase (ESBL), and carbapenem resistant (CR) β-lactamase (bla) genes and compared the genotype to the AST phenotype in select isolates. All bla_NDM-1 (9/9) and the majority of bla_NDM-1/OXA-48 (3/4) containing isolates were resistant to CAZ/AVI as predicted by WGS. The combination of ATM and CAZ/AVI restored susceptibility by disk diffusion assay. Unexpectedly, clinical Kp isolates bearing bla_KPC-8 (V240G) and bla_KPC-14 (G242 and T243 deletion) did not test fully resistant to CAZ/AVI. Lastly, despite the complexity of the β-lactamase background, CAZ/AVI retained potency. Presumed phenotypes conferred by AMR determinants need to be tested if therapeutic decisions are being guided by their presence or absence.

尽管多种抗菌素耐药性 (AMR) 决定因素可以赋予相同的体外抗菌药敏试验 (AST) 表型，但它们对最佳治疗选择的不同影响尚不确定。使用跨越 3.5 年的大量基于人群的临床菌株集合，我们应用 WGS 来检测抑制剂抗性 (IR)、超广谱 β-内酰胺酶 (ESBL) 和碳青霉烯抗性 (CR) β-内酰胺酶 ( bla )基因并将基因型与选定分离株中的 AST 表型进行比较。所有bla _NDM-1 (9/9) 和大部分bla _NDM-1/OXA-48WGS 预测，含有 (3/4) 的分离株对 CAZ/AVI 具有抗性。ATM 和 CAZ/AVI 的组合通过磁盘扩散试验恢复了敏感性。出乎意料的是，带有bla _KPC-8 (V240G) 和bla _KPC-14（G242 和 T243 缺失）的临床Kp分离株并未测试对 CAZ/AVI 具有完全抗性。最后，尽管 β-内酰胺酶背景复杂，CAZ/AVI 仍保持效力。如果治疗决策是由 AMR 决定因素赋予的假定表型，则需要对其进行测试。