Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.
Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.
Clin Microbiol Infect. 2021 Apr;27(4):583-589. doi: 10.1016/j.cmi.2020.05.012. Epub 2020 May 24.
The 'hypervirulent' variant of Klebsiella pneumoniae (hvKp) is a predominant cause of community-acquired pyogenic liver abscess in Asia, and is an emerging pathogen in Western countries. hvKp infections have demonstrated 'metastatic' dissemination in immunocompetent hosts, an unusual mode of infection associated with severe complications. Two cases alerted us to the possible presence of hvKp at our hospital, both involving elderly Hispanic males who presented with recurrent fever, bacteraemia, epigastric pain and liver abscesses/phlegmon, thus prompting an assessment of hvKp prevalence.
A surveillance of K. pneumoniae blood, body fluid and wound isolates was conducted using real-time PCR to detect virulence-associated genes (uni-rmpA, iucA and peg344). Positive isolates were further characterized by wzi gene sequencing to determine capsular types (K-type) and by multilocus sequence typing and pulsed-field gel electrophoresis to determine strain relatedness.
Four-hundred and sixty-three K. pneumoniae isolates, derived from 412 blood, 21 body fluids and 30 abdominal wound specimens, were screened over a 3-year period. Isolates included 98 multidrug-resistant strains. Eighteen isolates from 17 patients, including two from the index patient, screened positive for all three virulence genes. Sixteen of 18 positive isolates had K-types associated with hvKp, and isolates from different patients were unrelated strains, indicating likely community acquisition. Of 13 patients with significant morbidity, five died; eight patients had co-existing hepatobiliary disease, and six had diabetes mellitus.
Multiple strains of hvKp are emerging in New York City and are associated with high mortality relative to multidrug-resistant and classical Klebsiella infections. Co-existing hepatobiliary disease appears to be a potential risk factor for these infections.
产酸克雷伯菌（Klebsiella pneumoniae）的“超级毒力”变异株（hvKp）是亚洲社区获得性化脓性肝脓肿的主要病原体，也是西方国家新兴的病原体。hvKp 感染在免疫功能正常的宿主中表现出“转移性”播散，这是一种与严重并发症相关的不常见感染模式。两例病例引起了我们对医院中可能存在 hvKp 的警觉，这两例病例均涉及老年西班牙裔男性，他们表现为反复发热、菌血症、上腹痛和肝脓肿/蜂窝织炎，因此促使我们评估 hvKp 的流行率。
使用实时 PCR 对来自 412 份血液、21 份体液和 30 份腹部伤口标本的 463 株肺炎克雷伯菌血、体液和伤口分离株进行检测，以检测与毒力相关的基因（uni-rmpA、iucA 和 peg344）。阳性分离株进一步通过 wzi 基因测序进行特征分析，以确定荚膜型（K 型），并通过多位点序列分型和脉冲场凝胶电泳确定菌株相关性。
在 3 年期间筛查了 463 株肺炎克雷伯菌分离株，这些分离株来自 412 份血液、21 份体液和 30 份腹部伤口标本。其中包括 98 株多药耐药菌株。17 例患者的 18 株分离株均携带所有 3 种毒力基因，其中包括 2 株来自首发患者。18 株阳性分离株中的 16 株与 hvKp 相关的 K 型，且不同患者的分离株是无关菌株，表明可能是社区获得性感染。在 13 例有显著发病的患者中，有 5 例死亡；8 例患者合并肝胆疾病，6 例患有糖尿病。
多重 hvKp 菌株正在纽约市出现，与多药耐药和经典肺炎克雷伯菌感染相比，死亡率更高。合并肝胆疾病似乎是这些感染的一个潜在危险因素。
