State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai Universitygrid.216938.7, Tianjin, China.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
Microbiol Spectr. 2022 Feb 23;10(1):e0267821. doi: 10.1128/spectrum.02678-21.
WCK 5222 (cefepime/zidebactam) is a β-lactam/β-lactamase inhibitor combination that is effective against a broad range of highly drug-resistant bacterial pathogens, including those producing metallo-β-lactamase. In this study, we isolated a multidrug-resistant Pseudomonas aeruginosa clinical strain that is resistant to a variety of β-lactam antibiotics and the ceftazidime-avibactam combination. A metallo-β-lactamase gene was identified on a self-transmissible megaplasmid in the strain, which confers the resistance to β-lactam antibiotics, leaving WCK 5222 potentially one of the last treatment resorts. passaging assay combined with whole-genome sequencing revealed mutations in the gene (encoding the zidebactam target protein PBP2) in the evolved resistant mutants. Among the mutations, a V516M mutation increased the bacterial virulence in a murine acute pneumonia model. Reconstitution of the mutations in the reference strain PAO1 verified their roles in the resistance to zidebactam and revealed their influences on cell morphology in the absence and presence of zidebactam. Microscale thermophoresis (MST) assays demonstrated that the mutations reduced the affinity between PBP2 and zidebactam to various extents. Overall, our results revealed that mutations in the gene might be a major cause of evolved resistance to WCK 5222 in clinical settings. Antibiotic resistance imposes a severe threat on human health. WCK 5222 is a β-lactam/β-lactamase inhibitor combination that is composed of cefepime and zidebactam. It is one of the few antibiotics in clinical trials that are effective against multidrug-resistant Pseudomonas aeruginosa, including those producing metallo-β-lactamases. Understanding the mechanisms and development of bacterial resistance to WCK 5222 may provide clues for the development of strategies to suppress resistant evolvement. In this study, we performed an passaging assay by using a multidrug-resistant P. aeruginosa clinical isolate. Our results revealed that mutations in the zidebactam target protein PBP2 play a major role in the bacterial resistance to WCK 5222. We further demonstrated that the mutations reduced the affinities between PBP2 and zidebactam and resulted in functional resistance of PBP2 to zidebactam.
WCK 5222（头孢吡肟/齐他培南）是一种β-内酰胺/β-内酰胺酶抑制剂合剂，对广泛的高度耐药细菌病原体有效，包括产金属β-内酰胺酶的病原体。在这项研究中，我们分离到一株对多种β-内酰胺抗生素和头孢他啶-阿维巴坦合剂耐药的多药耐药铜绿假单胞菌临床分离株。在该菌株中，一种金属β-内酰胺酶基因位于一个可自我传递的大型质粒上，该基因赋予对β-内酰胺抗生素的耐药性，使 WCK 5222 成为潜在的最后治疗手段之一。通过传代实验结合全基因组测序，我们在进化的耐药突变体中发现了 基因（编码齐他培南靶蛋白 PBP2）的突变。在这些突变中，V516M 突变增加了细菌在小鼠急性肺炎模型中的毒力。在参考菌株 PAO1 中重建这些突变，证实了它们在对齐他培南耐药中的作用，并揭示了它们在没有和存在齐他培南时对细胞形态的影响。微量热泳动（MST）测定表明，这些突变在不同程度上降低了 PBP2 与齐他培南之间的亲和力。总的来说，我们的研究结果表明， 基因中的突变可能是临床环境中对 WCK 5222 进化耐药的主要原因。
抗生素耐药性对人类健康构成严重威胁。WCK 5222 是一种β-内酰胺/β-内酰胺酶抑制剂合剂，由头孢吡肟和齐他培南组成。它是临床试验中为数不多的对包括产金属β-内酰胺酶在内的多药耐药铜绿假单胞菌有效的抗生素之一。了解细菌对 WCK 5222 耐药性的机制和发展可能为抑制耐药性演变提供策略制定的线索。在这项研究中，我们通过使用多药耐药铜绿假单胞菌临床分离株进行传代实验。结果表明，齐他培南靶蛋白 PBP2 的突变在细菌对 WCK 5222 的耐药性中起主要作用。我们进一步证明，这些突变降低了 PBP2 与齐他培南之间的亲和力，并导致 PBP2 对齐他培南产生功能性耐药。
