Department of Rehabilitation Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, China.
Blood Center of Zhejiang Provincegrid.410621.0, Hangzhou, Zhejiang, China.
Microbiol Spectr. 2022 Feb 23;10(1):e0186921. doi: 10.1128/spectrum.01869-21. Epub 2022 Jan 12.
Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has become a serious challenge in the clinic. Recently, the prevalence of CRPA isolates carrying the gene has been increasing in China. Ceftazidime-avibactam (CZA) has shown good efficacy against large portions of KPC-2-producing CRPA strains. However, with the increasing usage of this drug, CZA resistance in CRPA strains has been reported. Here, we reported for the first time that resistance of the ST463 CRPA strain to CZA was caused by a novel variant in the KPC gene that arose after CZA exposure. The CRPA strain PA2207 is a carbapenem- and CZA-resistant strain that harbors a mutated gene, named . Cloning and expression of in Escherichia coli DH5α revealed that KPC-90 led to a 64-fold increase in the MIC value of CZA. Conjugation experiments further confirmed that was located on a conjugative plasmid. Whole-genome sequencing analysis showed that this plasmid had high sequence similarity to a previously reported novel -harboring plasmid in a clinical P. aeruginosa strain isolated in China. In addition, overexpression of an efflux pump (MexXY-OprM) might be associated with the CZA resistance phenotype, as determined by reverse transcription-quantitative PCR and efflux pump inhibition experiments. For the first time, we reported a KPC variant, KPC-90, in a clinical ST463 CRPA strain with CZA resistance that was mediated by a 2 amino acid insertion outside the KPC omega-loop region. Our study further highlights that diverse KPC variants that mediate CZA resistance have emerged in the CRPA strain. Furthermore, KPC-90 mutation combined with efflux pump overexpression resulted in a high level of resistance to CZA in the PA2207 isolate. Effective surveillance should be conducted to prevent CZA resistance from spreading in the CRPA strain. For the first time, we reported a KPC variant, KPC-90, in a clinical ST463 CRPA strain with CZA resistance. CZA resistance was mediated by a 2 amino acid insertion outside the KPC omega-loop region in CRPA. Our study further emphasized that CZA resistance caused by gene mutation could be selected in CRPA after CZA therapy. Considering the widespread presence of the ST463 CRPA strain in China, clinicians should pay attention to the risk of the development of CZA resistance in CRPA strains under treatment pressure.
耐碳青霉烯铜绿假单胞菌（CRPA）在临床上已成为严重的挑战。最近，在中国，携带 基因的 CRPA 分离株的流行率一直在增加。头孢他啶-阿维巴坦（CZA）对大部分 KPC-2 产生的 CRPA 菌株具有良好的疗效。然而，随着该药物的使用日益增加，已经报道了 CRPA 菌株对 CZA 的耐药性。在这里，我们首次报道，CRPA 菌株 ST463 对 CZA 的耐药性是由于 CZA 暴露后 KPC 基因发生的一种新型变异引起的。PA2207 是一种耐碳青霉烯类和 CZA 的 CRPA 菌株，携带一种突变的 基因，命名为 。在大肠杆菌 DH5α 中克隆和表达 表明，KPC-90 导致 CZA 的 MIC 值增加了 64 倍。接合实验进一步证实 位于可接合质粒上。全基因组测序分析表明，该质粒与中国临床分离的铜绿假单胞菌中先前报道的一种新型 携带质粒具有高度相似性。此外，通过逆转录定量 PCR 和外排泵抑制实验确定，外排泵（MexXY-OprM）的过度表达可能与 CZA 耐药表型有关。我们首次报道了一种临床 ST463 CRPA 菌株中的 KPC 变体 KPC-90，该变体介导 CZA 耐药性是由于 KPC omega 环区域外的 2 个氨基酸插入所致。我们的研究进一步强调，在 CRPA 菌株中出现了多种介导 CZA 耐药性的 KPC 变体。此外，KPC-90 突变与外排泵过度表达相结合，导致 PA2207 分离株对 CZA 的耐药水平很高。应进行有效的监测，以防止 CZA 耐药性在 CRPA 菌株中传播。我们首次报道了一种临床 ST463 CRPA 菌株中的 KPC 变体 KPC-90，该变体介导 CZA 耐药性是由于 CRPA 中的 KPC omega 环区域外的 2 个氨基酸插入所致。我们的研究进一步强调，在 CZA 治疗后，CRPA 中 基因的突变可选择 CZA 耐药性。鉴于中国 ST463 CRPA 菌株的广泛存在，临床医生应注意在治疗压力下 CRPA 菌株中 CZA 耐药性的发展风险。
