Abstract

Background

Multidrug-resistant (MDR) bacteria are frequently defined using the criteria established by Magiorakos et al [Clin Microbiol Infect 2012;18:268–81]. Difficult-to-treat resistance (DTR) [Kadri et al, Clin Infect Dis 2018;67:1803–14] is a novel approach to defining resistance in gram-negative bacilli focusing on treatment-limiting resistance to first-line agents (all β-lactams and fluoroquinolones).

Methods

Clinical and Laboratory Standards Institute–defined broth microdilution minimum inhibitory concentrations (MICs) were determined for imipenem/relebactam, ceftolozane/tazobactam, and comparators against respiratory, intraabdominal, and urinary isolates of Enterobacterales (n = 10 516) and Pseudomonas aeruginosa (n = 2732) collected in 26 US hospitals in 2015–2017.

Results

Among all Enterobacterales, 1.0% of isolates were DTR and 15.6% were MDR; 8.4% of P. aeruginosa isolates were DTR and 32.4% were MDR. MDR rates for Enterobacterales and DTR and MDR rates for P. aeruginosa were significantly higher (P < .05) in isolates collected in intensive care units (ICUs) than in non-ICUs and in respiratory tract isolates than in intraabdominal or urinary tract isolates. In addition, 82.4% of DTR and 92.1% of MDR Enterobacterales and 62.2% of DTR and 82.2% of MDR P. aeruginosa were imipenem/relebactam-susceptible, and 1.5% of DTR and 65.8% of MDR Enterobacterales and 67.5% of DTR and 84.0% of MDR P. aeruginosa were ceftolozane/tazobactam-susceptible.

Conclusions

MDR phenotypes defined using the Magiorakos criteria may overcall treatment-limiting resistance in gram-negative bacilli. In the US, DTR Enterobacterales were infrequent, while MDR Enterobacterales isolates and DTR and MDR P. aeruginosa were common. Imipenem/relebactam (Enterobacterales, P. aeruginosa) and ceftolozane/tazobactam (P. aeruginosa) retained in vitro activity against most DTR and MDR isolates.

中文翻译：

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亚胺培南/瑞巴坦和头孢洛扎/他唑巴坦对难治耐药和多重耐药表型革兰氏阴性杆菌临床分离株的体外活性——监测抗菌素耐药趋势的研究，美国 2015-2017

摘要

背景

多重耐药 (MDR) 细菌经常使用 Magiorakos 等人建立的标准进行定义 [Clin Microbiol Infect 2012;18:268-81]。难治性耐药 (DTR) [Kadri 等人，Clin Infect Dis 2018;67:1803-14] 是一种定义革兰氏阴性杆菌耐药性的新方法，重点是对一线药物的治疗限制性耐药性（所有β-内酰胺类和氟喹诺酮类）。

方法

临床和实验室标准协会确定了亚胺培南/瑞巴坦、头孢唑烷/他唑巴坦以及针对呼吸道、腹腔内和泌尿系统肠杆菌（n = 10 516）和铜绿假单胞菌（n = 2732) 于 2015-2017 年在 26 家美国医院收集。

结果

在所有肠杆菌中，1.0% 的分离株为 DTR，15.6% 为 MDR；8.4% 的铜绿假单胞菌分离株为 DTR，32.4% 为 MDR。在重症监护病房 (ICU) 收集的分离株中，肠杆菌属的MDR 率和 DTR 以及铜绿假单胞菌的MDR 率显着高于非 ICU 中的分离株（P <  .05），呼吸道分离株中的MDR 率显着高于腹内或泌尿道内分离株。此外，82.4% 的 DTR 和 92.1% 的耐多药肠杆菌以及 62.2% 的 DTR 和 82.2% 的耐多药铜绿假单胞菌对亚胺培南/瑞巴坦敏感，1.5% 的 DTR 和 65.8% 的耐多药肠杆菌和 67% MDR 的 84.0%铜绿假单胞菌对ceftolozane/他唑巴坦敏感。

结论

使用 Magiorakos 标准定义的 MDR 表型可能会夸大革兰氏阴性杆菌的治疗限制性耐药性。在美国，DTR肠杆菌属不常见，而 MDR肠杆菌属分离株和 DTR 和 MDR铜绿假单胞菌很常见。亚胺培南/瑞巴坦（肠杆菌属，铜绿假单胞菌）和头孢洛扎/他唑巴坦（铜绿假单胞菌）在体外对大多数 DTR 和 MDR 分离株的活性保持不变。