Pediatric Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
J Microbiol Methods. 2012 Jun;89(3):159-66. doi: 10.1016/j.mimet.2012.03.014. Epub 2012 Mar 30.
The notoriously multi-resistant Staphylococcus haemolyticus is an emerging pathogen causing serious infections in immunocompromised patients. Defining the population structure is important to detect outbreaks and spread of antimicrobial resistant clones. Currently, the standard typing technique is pulsed-field gel electrophoresis (PFGE). In this study we describe novel molecular typing schemes for S. haemolyticus using multi locus sequence typing (MLST) and multi locus variable number of tandem repeats (VNTR) analysis. Seven housekeeping genes (MLST) and five VNTR loci (MLVF) were selected for the novel typing schemes. A panel of 45 human and veterinary S. haemolyticus isolates was investigated. The collection had diverse PFGE patterns (38 PFGE types) and was sampled over a 20 year-period from eight countries. MLST resolved 17 sequence types (Simpsons index of diversity [SID]=0.877) and MLVF resolved 14 repeat types (SID=0.831). We found a low sequence diversity. Phylogenetic analysis clustered the isolates in three (MLST) and one (MLVF) clonal complexes, respectively. Taken together, neither the MLST nor the MLVF scheme was suitable to resolve the population structure of this S. haemolyticus collection. Future MLVF and MLST schemes will benefit from addition of more variable core genome sequences identified by comparing different fully sequenced S. haemolyticus genomes.
众所周知，溶血葡萄球菌是一种多耐药病原体，可导致免疫功能低下患者发生严重感染。明确其种群结构对于发现暴发疫情和耐药克隆的传播非常重要。目前，标准的分型技术是脉冲场凝胶电泳（PFGE）。本研究通过多位点序列分型（MLST）和多位点可变数目串联重复分析（MLVF），描述了溶血葡萄球菌的新型分子分型方案。选择了七个看家基因（MLST）和五个 VNTR 基因座（MLVF）用于新型分型方案。本panel 包含了 45 株人源和兽医源溶血葡萄球菌分离株。该分离株集具有多样化的 PFGE 图谱（38 种 PFGE 型），并且在 20 年的时间内，从 8 个国家进行了采样。MLST 鉴定出 17 种序列型（多样性指数[SID]=0.877），MLVF 鉴定出 14 种重复型（SID=0.831）。我们发现分离株的序列多样性较低。系统进化分析将分离株聚类为三个（MLST）和一个（MLVF）克隆复合体。总的来说，无论是 MLST 方案还是 MLVF 方案，都无法解决该溶血葡萄球菌分离株集的种群结构问题。未来的 MLVF 和 MLST 方案将受益于通过比较不同完全测序的溶血葡萄球菌基因组，添加更多由核心基因组序列差异识别的可变基因座。
