PDF(Pubmed)
Abstract：
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 blaDIM-2 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. In vitro passaging assay combined with whole-genome sequencing revealed mutations in the pbpA 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 pbpA gene might be a major cause of evolved resistance to WCK 5222 in clinical settings. IMPORTANCE 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 in vitro 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.
摘要：
WCK5222（头孢吡肟/zidebartam）是一种β-内酰胺/β-内酰胺酶抑制剂组合，可有效对抗多种高度耐药的细菌病原体，包括那些产生金属-β-内酰胺酶的。在这项研究中,我们分离出一株对多种β-内酰胺类抗生素和头孢他啶-阿维巴坦联合耐药的铜绿假单胞菌临床菌株。在该菌株的自传播大质粒上鉴定出金属β-内酰胺酶基因blaDIM-2，这赋予了对β-内酰胺抗生素的耐药性，离开WCK5222可能是最后的治疗手段之一。与全基因组测序相结合的体外传代测定揭示了进化的抗性突变体中pbpA基因（编码齐达巴坦靶蛋白PBP2）的突变。在突变中，V516M突变增加了小鼠急性肺炎模型中的细菌毒力。参考菌株PAO1中突变的重建验证了它们在对齐德巴坦的抗性中的作用，并揭示了在不存在和存在齐德巴坦的情况下它们对细胞形态的影响。微尺度热电泳（MST）测定表明，突变在不同程度上降低了PBP2和zidebartam之间的亲和力。总的来说,我们的结果显示,pbpA基因突变可能是临床环境中WCK5222进化耐药的主要原因.重要性抗生素耐药性对人类健康构成严重威胁。WCK5222是一种β-内酰胺/β-内酰胺酶抑制剂组合，由头孢吡肟和齐达巴坦组成。它是临床试验中为数不多的对多重耐药铜绿假单胞菌有效的抗生素之一，包括产生金属-β-内酰胺酶的那些。了解细菌对WCK5222的抗性机制和发展可能为制定抑制抗性进化的策略提供线索。在这项研究中,我们使用耐多药铜绿假单胞菌临床分离株进行了体外传代试验.我们的结果表明，齐达巴坦靶蛋白PBP2的突变在细菌对WCK5222的抗性中起主要作用。我们进一步证明，这些突变降低了PBP2和齐德巴坦之间的亲和力，并导致PBP2对齐德巴坦的功能抗性。
