The Rapid Emergence of Tigecycline Resistance in bla(KPC-2) Harboring Klebsiella pneumoniae, as Mediated in Vivo by Mutation in tetA During Tigecycline Treatment.
The Rapid Emergence of Tigecycline Resistance in bla(KPC-2) Harboring Klebsiella pneumoniae, as Mediated in Vivo by Mutation in tetA During Tigecycline Treatment.
复制标题
替加环素治疗期间，tetA 突变在体内介导肺炎克雷伯菌 bla(KPC-2) 中替加环素耐药性的迅速出现
DOI：
10.3389/fmicb.2018.00648
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发表时间：
2018
影响因子：
5.2
通讯作者：
Yu Y
中科院分区：
文献类型：
--
作者：
Du X;He F;Shi Q;Zhao F;Xu J;Fu Y;Yu Y
替加环素是碳青霉烯类耐药肺炎克雷伯菌（CRKP）感染的最后治疗手段之一。替加环素耐药是CRKP临床治疗中常见的耐药现象，其机制尚未完全阐明。本研究分析了替加环素治疗期间感染CRKP的56岁女性患者的临床分离株中产生的替加环素耐药机制。连续克隆一致K.在替加环素治疗期间获得肺炎分离株。对分离株进行全基因组测序，并在敏感和耐药分离株中分析推定的单核苷酸多态性和插入和缺失突变。通过涉及转化和缀合的实验来检查所鉴定的感兴趣的基因。从患者体内采集了4株分离株，其中2株敏感，2株耐药。所有分离株均属于序列类型11（ST 11），并被归类为广泛耐药（XDR）。在替加克林耐药菌株中鉴定出TetA的一个氨基酸替换S251A。随后的转化实验证实了TetA变体（S251A）对替加环素耐药性的贡献。通过缀合实验证实了通过该突变转移替加环素耐药性的能力。通过Southern杂交和PCR检测，进一步证明tetA基因位于一个可转移的质粒上。在大肠杆菌EC 600转移接合子中的65 kb。我们的研究结果提供了直接的体内证据，tetA基因的进化可能导致携带tetA的CRKP临床菌株中替加环素治疗失败。此外，由突变的tetA介导的替加环素耐药性的转移能力是一个威胁。
Tigecycline is one of the last resort treatments for carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. Tigecycline resistance often occurs during the clinical treatment of CRKP, yet its mechanism has still not been clearly elucidated. This study presents an analysis of a tigecycline resistance mechanism that developed in clinical isolates from a 56-year-old female patient infected with CRKP during tigecycline treatment. Consecutive clonal consistent K. pneumoniae isolates were obtained during tigecycline treatment. Whole genome sequencing of the isolates was performed, and putative single nucleotide polymorphisms and insertion and deletion mutations were analyzed in susceptible and resistant isolates. The identified gene of interest was examined through experiments involving transformations and conjugations. Four isolates, two of which were susceptible and two resistant, were collected from the patient. All of the isolates belonged to Sequence Type 11 (ST11) and were classified as extensively drug resistant (XDR). One amino acid substitution S251A in TetA was identified in the tigecycline-resistant isolates. Subsequent transformation experiments confirmed the contribution of the TetA variant (S251A) to tigecycline resistance. The transfer capacity of tigecycline resistance via this mutation was confirmed by conjugation experiments. Using southern blot hybridization and PCR assays, we further proved that the tetA gene was located on a transferable plasmid of ca. 65 kb in an Escherichia coli EC600 transconjugant. Our results provide direct in vivo evidence that evolution in the tetA gene can lead to tigecycline treatment failure in CRKP clinical strains that carry tetA. Moreover, the transfer capacity of tigecycline resistance mediated by mutated tetA is a threat.