Emergence of Ceftazidime-Avibactam Resistance Due to Plasmid-Borne blaKPC-3 Mutations during Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infections
Emergence of Ceftazidime-Avibactam Resistance Due to Plasmid-Borne blaKPC-3 Mutations during Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infections
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DOI：
10.1128/aac.02097-16
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发表时间：
2017-03-01
影响因子：
4.9
通讯作者：
Clancy, Cornelius J.
中科院分区：
文献类型：
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作者：
Shields, Ryan K.;Chen, Liang;Clancy, Cornelius J.
头孢他啶-阿维巴坦是一种新型的β-内酰胺/β-内酰胺酶抑制剂，对产生碳青霉烯类肺炎克雷伯菌碳青霉烯酶(KPC)的耐碳青霉烯类肠杆菌(CRE)具有抗菌活性。我们报告了在治疗CRE感染过程中出现的第一例头孢他啶美韦巴坦耐药病例，并确定了耐药机制。3例头孢他啶-阿维巴坦耐药肺炎克雷伯菌在治疗10-19天后出现。对肺炎克雷伯菌对头孢他啶-阿维巴坦敏感和耐药的纵向分离株进行全基因组测序(WGS)以确定潜在的耐药机制。WGS发现了质粒携带的BLA(KPC-3)的突变，这在基线分离株中不存在。BLA(KPC-3)突变独立出现在一个新的序列类型258亚系的分离株中，并导致KPC-3酶的变异。通过测定头孢他啶-阿维巴坦和其他药物在肺炎克雷伯菌中的靶向基因破坏、质粒转移和blaKPC克隆到感受态大肠杆菌中的MIC值，证实这些突变是耐药决定因素。KPC-3基因变异对头孢他啶-阿维巴坦MICs的影响顺序为：D179Y/T243M双取代>；D179Y>；V240G。值得注意的是，突变使美罗培南最低抑菌浓度比基线降低了4倍，恢复了两名患者对肺炎克雷伯菌的敏感性。头孢吡肟和头孢曲松对D179Y/T243M和D179Y变异株的最低抑菌浓度也降低了4倍，但敏感性没有恢复。逆转录-聚合酶链式反应显示，在基线分离株中，编码D179Y/T243M和D179Y变异体的bla(Kpc-3)的表达低于bla(kpc-3)的表达。总之，肺炎克雷伯菌在接触头孢他啶-阿巴坦后10至19天内出现耐药相关BLA(KPC-3)突变是令人担忧的，但如果某些分离株恢复对碳青霉烯的敏感性，临床影响可能会得到改善。
Ceftazidime-avibactam is a novel beta lactam/ beta-lactamase inhibitor with activity against carbapenem-resistant Enterobacteriaceae (CRE) that produce Kleb-siella pneumoniae carbapenemase (KPC). We report the first cases of ceftazidimeavibactam resistance to develop during treatment of CRE infections and identify resistance mechanisms. Ceftazidime-avibactam-resistant K. pneumoniae emerged in three patients after ceftazidime-avibactam treatment for 10 to 19 days. Wholegenome sequencing (WGS) of longitudinal ceftazidime-avibactam-susceptible and -resistant K. pneumoniae isolates was used to identify potential resistance mechanisms. WGS identified mutations in plasmid-borne bla(KPC-3), which were not present in baseline isolates. bla(KPC-3) mutations emerged independently in isolates of a novel sequence type 258 sublineage and resulted in variant KPC-3 enzymes. The mutations were validated as resistance determinants by measuring MICs of ceftazidime-avibactam and other agents following targeted gene disruption in K. pneumoniae, plasmid transfer, and blaKPC cloning into competent Escherichia coli. In rank order, the impact of KPC-3 variants on ceftazidime-avibactam MICs was as follows: D179Y/T243M double substitution > D179Y > V240G. Remarkably, mutations reduced meropenem MICs >= 4-fold from baseline, restoring susceptibility in K. pneumoniae from two patients. Cefepime and ceftriaxone MICs were also reduced >= 4-fold against D179Y/T243M and D179Y variant isolates, but susceptibility was not restored. Reverse transcription-PCR revealed that expression of bla(KPC-3) encoding D179Y/T243M and D179Y variants was diminished compared to bla(KPC-3) expression in baseline isolates. In conclusion, the development of resistance-conferring bla(KPC-3) mutations in K. pneumoniae within 10 to 19 days of ceftazidime-avibactam exposure is troubling, but clinical impact may be ameliorated if carbapenem susceptibility is restored in certain isolates.