The growing prevalence and diversity of carbapenemase producers among carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates warrants an expansion of detection capabilities. The purpose of this study was to evaluate the performance of the commercially available Xpert Carba-R (Carba-R) and the research-use-only Xpert Carba-R NxG (Carba-R NxG) in a global collection of P. aeruginosa. The challenge set included 123 P. aeruginosa clinical isolates from 12 countries. Isolates were previously categorized via PCR or whole-genome sequencing. Carbapenemase classes tested include VIM, IMP, NDM, SPM, KPC, and GES. Non-carbapenemase (non-CP)-harboring isolates were also tested (negative control). Isolates were tested using the Carba-R NxG and the Carba-R tests per the manufacturer’s instructions. Carba-R NxG testing was completed by Cepheid (Sunnyvale, CA), blinded to genotype. Both assays gave negative results for all non-CP isolates and positive results for all VIM, NDM, and KPC isolates. An improvement in IMP detection among isolates was observed (100% detection by Carba-R NxG versus 58% by Carba-R). All SPM and GES isolates, targets not present in commercially available Carba-R, were positive by Carba-R NxG. Two isolates harbored both VIM and GES, while a third isolate contained VIM and NDM. The Carba-R NxG identified both targets in all 3 isolates, while the Carba-R was negative for both GES-containing isolates. Overall, the Carba-R NxG successfully categorized 100% of isolates tested compared with 68% for its predecessor. The Carba-R NxG will expand the detection spectrum of the current Carba-R assay to include SPM, GES, and expanded IMP variants, increasing the global utility of the test.

中文翻译：

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Xpert Carba-R NxG检测用于铜绿假单胞菌分离物全球攻击组中碳青霉烯酶基因检测的评估。

耐碳青霉烯的铜绿假单胞菌（CRPA）分离株中碳青霉烯酶生产者的流行和多样性不断增加，因此有必要扩大检测能力。这项研究的目的是评估铜绿假单胞菌在全球范围内的市售Xpert Carba-R（Carba-R）和仅供研究使用的Xpert Carba-R NxG（Carba-R NxG）的性能。挑战集包括123铜绿假单胞菌来自12个国家/地区的临床分离株。分离物以前是通过PCR或全基因组测序进行分类的。测试的碳青霉烯酶类别包括VIM，IMP，NDM，SPM，KPC和GES。还测试了非卡巴培南酶（非CP）的分离株（阴性对照）。按照制造商的说明，使用Carba-R NxG和Carba-R测试对分离物进行测试。不知基因型的Cepheid（加利福尼亚州桑尼维尔）完成了Carba-R NxG测试。两种检测均对所有非CP分离物给出阴性结果，对所有VIM，NDM和KPC分离物给出阳性结果。观察到分离株中IMP检测的改善（Carba-R NxG检测为100％，而Carba-R检测为58％）。Carba-R NxG对所有SPM和GES分离株（市售Carba-R中不存在的靶标）呈阳性。VIM和GES都有两个隔离株，而第三个隔离区包含VIM和NDM。Carba-R NxG在所有3个分离株中都鉴定出了两个靶标，而Carba-R对两个包含GES的分离株均呈阴性。总体而言，Carba-R NxG成功地将100％的分离株进行了分类，而之前的分离株为68％。Carba-R NxG将扩大当前Carba-R分析的检测范围，使其包括SPM，GES和扩展的IMP变体，从而提高测试的全球实用性。