Characterization of an Enterococcus faecium small-colony variant isolated from blood culture
Characterization of an Enterococcus faecium small-colony variant isolated from blood culture
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DOI：
10.1016/j.ijmm.2011.07.001
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发表时间：
2012-01-01
影响因子：
4.1
通讯作者：
Schulte, Bent
中科院分区：
文献类型：
--
作者：
Groebner, Sabine;Beck, Julia;Schulte, Bent
细菌的小菌落变体（SCV）是生长缓慢的亚群，与野生型相比，由于细胞内存活率更高，可能导致潜伏或复发性感染。不典型的菌落形态和改变的生化谱可能导致SCV菌株鉴定失败。我们在这里报告的第一次屎肠球菌SCV表型的分离。一个65岁的妇女急性髓性白血病谁开发的诱导化疗期间出现脓毒症的症状的情况下。E.从血培养物中分离出具有正常和SCV表型的屎肠菌。同时尿培养E.粪菌表明菌血症起源于泌尿道。SCV表型的特点是非典型的生长行为。电子显微镜分析显示扰动的子细胞的分离和细胞壁材料的积累。因此，SCV变异体表现出功能障碍或缺乏自发性自溶，而正常表型则没有。通过本实验室实施的MALDI-TOF MS分析精确鉴定了屎囊菌SCV。因此，越来越多地使用MALDI-TOF MS分析来鉴定细菌可能是检测SCV变体的适当工具，SCV变体的诊断对于临床结果和抗生素治疗具有重要意义。(C)2011年由Elsevier GmbH出版。
Small-colony variants (SCVs) of bacteria are slow-growing subpopulations which can cause latent or recurrent infections due to better intracellular survival compared to their wild-type counterparts. Atypical colony morphology and altered biochemical profile may lead to failure in identification of SCV strains. We here report for the first time the isolation of an Enterococcus faecium SCV phenotype. The case of a 65-year-old woman with acute myeloid leukaemia who developed symptoms of sepsis during induction chemotherapy is presented. E. faecium with normal and SCV phenotype was isolated from blood cultures. At the same time urine culture was positive with E. faecium suggesting that bacteraemia originated from the urinary tract. The SCV phenotype was characterized by atypical growth behaviour. Electron microscopic analyses revealed perturbation of the separation of daughter cells and the accumulation of cell wall material. Accordingly, the SCV variant showed a dysfunction or lack of spontaneous autolysis whereas the normal phenotype did not.In contrast to conventional identification systems based on biochemical characteristics, the E. faecium SCV was precisely identified by MALDI-TOF MS analysis implemented in our laboratory. Hence, the increasing use of MALDI-TOF MS analysis for the identification of bacteria might be an appropriate tool for the detection of SCV variants, the diagnosis of which is of importance for the clinical outcome and the antibiotic treatment. (C) 2011 Published by Elsevier GmbH.