Resistance to aztreonam in combination with non-ß-lactam ß-lactamase inhibitors due to the layering of mechanisms in Escherichia coli identified following mixed culture selection
Resistance to aztreonam in combination with non-ß-lactam ß-lactamase inhibitors due to the layering of mechanisms in Escherichia coli identified following mixed culture selection
复制标题
由于混合培养选择后确定的大肠杆菌分层机制，对氨曲南与非内酰胺酶抑制剂联合产生耐药性
DOI：
10.1101/615336
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Cheung C
中科院分区：
文献类型：
--
作者：
Cheung C
双环硼酸酯是一类新的具有潜在重要意义的β-内酰胺酶抑制剂，具有抑制所有分子类型的β-内酰胺酶（包括移动的金属β-内酰胺酶）的能力。方法将过夜培养物接种在含有递增浓度的氨曲南的琼脂上，10 mg/L浓度的抑制剂。结果当使用含有一个大肠杆菌（TEM-1，CTX-M-15，CMY-4生产者）和一个肺炎克雷伯菌（SHV-12，CTX-M-15，NDM-1生产者）的混合过夜培养物时，从K. pneumoniae进入E.大肠杆菌产生了氨曲南/硼酸盐耐药衍生物。ConclusionsHigh-level生产的三个双环硼酸盐敏感酶（CMY-4，CTX-M-15，SHV-12）能够水解氨曲南加上TEM-1，结合抑制剂，克服了固定的抑制剂剂量使用。这仅在使用混合培养物进行选择时才被发现。考虑到在人类定植的细菌群体中常见的无数β-内酰胺酶基因的合并，在临床前分析中检测产生β-内酰胺酶抑制剂耐药性的可能性时，这种混合培养方法应是标准方法，这似乎是谨慎的。
BackgroundBicyclic boronates are a new and potentially important class of β-lactamase inhibitor, with the ability to inhibit β-lactamases from all molecular classes, including mobile metallo-β-lactamases.ObjectiveOur objective was to identify mutants resistant to the actions of the bicyclic boronate inhibitor2, when being used in combination with aztreonam.MethodsOvernight cultures were plated on to agar containing increasing concentrations of aztreonam with a fixed 10 mg/L concentration of the inhibitor. Resistant derivatives and parent strains were analysed by whole genome sequencing and LC-MS/MS proteomics to identify mechanism of resistance.ResultsWhen using a mixed overnight culture containing oneEscherichia coli(TEM-1, CTX-M-15, CMY-4 producer) and oneKlebsiella pneumoniae(SHV-12, CTX-M-15, NDM-1 producer) mobilisation of an IncX3 plasmid carryingblaSHV-12from theK. pneumoniaeinto theE. coligenerated an aztreonam/boronate resistant derivative.ConclusionsHigh-level production of three bicyclic boronate susceptible enzymes (CMY-4, CTX-M-15, SHV-12) capable of hydrolysing aztreonam plus TEM-1, which binds the inhibitor, overcomes the fixed inhibitor dose used. This was only identified when using a mixed culture for selection. It would seem prudent that to allow for coalescence of the myriad β-lactamase genes commonly found in bacterial populations colonising humans, this mixed culture approach should be the norm when testing the potential for generating β-lactamase inhibitor resistance in pre-clinical analysis.