Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore.
Division of Infectious Diseases, University Medicine Cluster, National University Health System, Singapore.
Sci Rep. 2016 Jul 13;6:29316. doi: 10.1038/srep29316.
Hypervirulent Klebsiella pneumoniae is an emerging cause of community-acquired pyogenic liver abscess. First described in Asia, it is now increasingly recognized in Western countries, commonly afflicting those with Asian descent. This raises the question of genetic predisposition versus geospecific strain acquisition. We leveraged on the Antibiotics for Klebsiella Liver Abscess Syndrome Study (A-KLASS) clinical trial ongoing in ethnically diverse Singapore, to prospectively examine the profiles of 70 patients together with their isolates' genotypic and phenotypic characteristics. The majority of isolates belonged to capsule type K1, a genetically homogenous group corresponding to sequence-type 23. The remaining K2, K5, K16, K28, K57 and K63 isolates as well as two novel cps isolates were genetically heterogeneous. K1 isolates carried higher frequencies of virulence-associated genes including rmpA (regulator of mucoid phenotype A), kfu (Klebsiella ferric uptake transporter), iuc (aerobactin), iro (salmochelin) and irp (yersiniabactin) than non-K1 isolates. The Chinese in our patient cohort, mostly non-diabetic, had higher prevalence of K1 infection than the predominantly diabetic non-Chinese (Malays, Indian and Caucasian). This differential susceptibility to different capsule types among the various ethnic groups suggests patterns of transmission (e.g. environmental source, familial transmission) and/or genetic predisposition unique to each race despite being in the same geographical location.
高毒力肺炎克雷伯菌是一种新兴的社区获得性化脓性肝脓肿的病因。它最初在亚洲被描述,现在在西方国家也越来越被认识到,通常影响具有亚洲血统的人。这就提出了遗传易感性与地理特异性菌株获得之间的问题。我们利用正在新加坡进行的具有多种族的抗生素治疗肝脓肿综合征研究(A-KLASS)临床试验,前瞻性地检查了 70 名患者及其分离株的基因型和表型特征。大多数分离株属于荚膜类型 K1,这是一个遗传上同质的群体,对应于序列型 23。其余的 K2、K5、K16、K28、K57 和 K63 分离株以及两个新的 cps 分离株在遗传上是异质的。K1 分离株携带更高频率的与毒力相关的基因,包括 rmpA(粘液表型 A 的调节剂)、kfu(肺炎克雷伯氏菌铁摄取转运蛋白)、iuc(aerobactin)、iro(salmochelin)和 irp(yersiniabactin),比非 K1 分离株更高。在我们的患者队列中,中国人大多没有糖尿病,K1 感染的发生率高于主要是糖尿病的非中国人(马来人、印度人和高加索人)。不同种族之间对不同荚膜类型的这种不同敏感性表明了传播模式(例如环境源、家族传播)和/或每个种族特有的遗传易感性,尽管它们处于同一地理位置。