Very few antimicrobial agents remain active against Pseudomonas aeruginosa and Klebsiella pneumoniae in some geographic regions. We evaluated the in vitro activity of ceftazidime–avibactam, ceftolozane–tazobactam, and comparator agents against 6,210 P. aeruginosa and 6,041 K. pneumoniae isolates consecutively collected from 85 U.S. medical centers across 37 states in 2016–2018. Antimicrobial susceptibility was determined by reference broth microdilution method. K. pneumoniae isolates found to have elevated MICs for broad-spectrum cephalosporins were submitted to whole-genome sequencing analysis to detect resistance genes. Ceftazidime–avibactam (97.1% susceptible [S]) and ceftolozane–tazobactam (97.0%S) were the most active compounds against P. aeruginosa and retained activity against meropenem-nonsusceptible (88.5–89.0%S), piperacillin–tazobactam-nonsusceptible (86.6–87.0%S), and other resistant subsets of isolates. The most active agents against K. pneumoniae per CLSI criteria were ceftazidime–avibactam (>99.9%S), amikacin (98.4%S), and meropenem (97.1%S). Ceftolozane–tazobactam was active against 95.3% of K. pneumoniae but showed limited activity against extended-spectrum β-lactamase and carbapenemase producers (82.9% and 0.0%S, respectively).

中文翻译：

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头孢他啶-阿维巴坦、头孢他啶-他唑巴坦和对比剂在 2016-2018 年对来自美国医疗中心的铜绿假单胞菌和肺炎克雷伯菌分离株的抗菌活性

在某些地理区域，很少有抗菌剂对铜绿假单胞菌和肺炎克雷伯菌保持活性。我们评估了头孢他啶-阿维巴坦、头孢唑烷-他唑巴坦和对照剂对2016-2018 年从 37 个州的 85 个美国医疗中心连续收集的6,210株铜绿假单胞菌和 6,041株肺炎克雷伯菌分离株的体外活性。通过参考肉汤微量稀释法测定抗菌药物敏感性。肺炎克雷伯菌对广谱头孢菌素 MIC 升高的分离株进行全基因组测序分析以检测耐药基因。头孢他啶-阿维巴坦（97.1% 敏感 [S]）和头孢唑烷-他唑巴坦（97.0% S）是对铜绿假单胞菌最有效的化合物，并保留了对美罗培南不敏感（88.5-89.0%S）、哌拉西林-他唑巴坦不敏感（ 86.6–87.0%S) 和其他耐药菌株亚群。根据CLSI 标准，对肺炎克雷伯菌最有效的药物是头孢他啶-阿维巴坦 (>99.9%S)、阿米卡星 (98.4%S) 和美罗培南 (97.1%S)。头孢唑烷-他唑巴坦对 95.3% 的肺炎克雷伯菌有活性 但对超广谱 β-内酰胺酶和碳青霉烯酶生产者的活性有限（分别为 82.9% 和 0.0%S）。