在俄亥俄州东北部的一家儿童和青年长期护理机构中，“沉默”传播产碳青霉烯酶肺炎克雷伯菌的分离株。
"Silent" dissemination of Klebsiella pneumoniae isolates bearing K. pneumoniae carbapenemase in a long-term care facility for children and young adults in Northeast Ohio.
机构信息
Department of Medicine, Jacobi Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA.
出版信息
Clin Infect Dis. 2012 May;54(9):1314-21. doi: 10.1093/cid/cis036.
BACKGROUND
Klebsiella pneumoniae isolates harboring the K. pneumoniae carbapenemase gene (bla(KPC)) are creating a significant healthcare threat in both acute and long-term care facilities (LTCFs). As part of a study conducted in 2004 to determine the risk of stool colonization with extended-spectrum cephalosporin-resistant gram-negative bacteria, 12 isolates of K. pneumoniae that exhibited nonsusceptibility to extended-spectrum cephalosporins were detected. All were gastrointestinal carriage isolates that were not associated with infection.
METHODS
Reassessment of the carbapenem minimum inhibitory concentrations using revised 2011 Clinical Laboratory Standards Institute breakpoints uncovered carbapenem resistance. To further investigate, a DNA microarray assay, PCR-sequencing of bla genes, immunoblotting, repetitive-sequence-based PCR (rep-PCR) and multilocus sequence typing (MLST) were performed.
RESULTS
The DNA microarray detected bla(KPC) in all 12 isolates, and bla(KPC-3) was identified by PCR amplification and sequencing of the amplicon. In addition, a bla(SHV-11) gene was detected in all isolates. Immunoblotting revealed "low-level" production of the K. pneumoniae carbapenemase, and rep-PCR indicated that all bla(KPC-3)-positive K. pneumoniae strains were genetically related (≥98% similar). According to MLST, all isolates belonged to sequence type 36. This sequence type has not been previously linked with bla(KPC) carriage. Plasmids from 3 representative isolates readily transferred the bla(KPC-3) to Escherichia coli J-53 recipients.
CONCLUSIONS
Our findings reveal the "silent" dissemination of bla(KPC-3) as part of Tn4401b on a mobile plasmid in Northeast Ohio nearly a decade ago and establish the first report, to our knowledge, of K. pneumoniae containing bla(KPC-3) in an LTCF caring for neurologically impaired children and young adults.
背景
产碳青霉烯酶肺炎克雷伯菌（Klebsiella pneumoniae carbapenemase gene，bla(KPC)) 的分离株对急性和长期护理机构（long-term care facilities，LTCFs）的医疗保健构成了重大威胁。作为 2004 年进行的一项旨在确定对广谱头孢菌素耐药革兰氏阴性菌粪便定植风险的研究的一部分，检测到 12 株对广谱头孢菌素表现出不敏感性的肺炎克雷伯菌分离株。所有这些都是与感染无关的胃肠道定植分离株。
方法
使用修订后的 2011 年临床实验室标准协会（Clinical Laboratory Standards Institute）折点重新评估碳青霉烯类药物的最低抑菌浓度，发现碳青霉烯类药物耐药。为了进一步研究，进行了 DNA 微阵列分析、bla 基因的 PCR 测序、免疫印迹、重复序列基元 PCR（repetitive-sequence-based PCR，rep-PCR）和多位点序列分型（multilocus sequence typing，MLST）。
结果
12 株分离株的 DNA 微阵列均检测到 bla(KPC)，PCR 扩增和扩增子测序鉴定出 bla(KPC-3)。此外，所有分离株均检测到 bla(SHV-11)基因。免疫印迹显示“低水平”产 K. pneumoniae 碳青霉烯酶，rep-PCR 表明所有 bla(KPC-3)-阳性 K. pneumoniae 菌株在遗传上具有相关性（≥98%相似）。根据 MLST，所有分离株均属于序列型 36。该序列型以前与 bla(KPC)携带无关。3 个代表性分离株的质粒可将 bla(KPC-3)轻易转移至 E. coli J-53 受体。
结论
我们的研究结果揭示了 bla(KPC-3)作为 Tn4401b 一部分在近十年前在俄亥俄州东北部的移动质粒中“沉默”传播，并建立了第一个报告，据我们所知，在一家照顾神经损伤儿童和年轻人的长期护理机构中发现了携带 bla(KPC-3)的肺炎克雷伯菌。
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