Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, P.O. Box 66, FI-00014 University of Helsinki, Helsinki, Finland.
Appl Environ Microbiol. 2011 Feb;77(4):1196-203. doi: 10.1128/AEM.02412-10. Epub 2010 Dec 23.
In two previous studies dealing with lactic acid bacteria (LAB) from modified-atmosphere-packaged (MAP) broiler products and a broiler processing plant, several isolates remained unidentified. According to 16S rRNA gene sequence analysis, 36 isolates were assigned to the genus Enterococcus. Numerical analysis of combined HindIII and EcoRI ribopatterns of these isolates resulted in species-specific clusters that were congruent with the clusters obtained by both DNA-directed RNA polymerase subunit A (rpoA) and phenylalanyl-tRNA synthetase α chain (pheS) housekeeping gene analyses. In the analyses, a group of five isolates distinct from any known enterococcal species clustered together. The five isolates were positioned in the Enterococcus avium group, with E. devriesei being the closest phylogenetic neighbor. The DNA-DNA hybridization levels with E. devriesei ranged from 28.8 to 54.3% and indicated that these strains represented a novel species. The name Enterococcus viikkiensis sp. nov. is proposed, with strain DSM 24043(T) (LMG 26075(T)) being the type strain. Our study demonstrated that the identification of enterococci within the E. avium phylogenetic group demands polyphasic taxonomic approaches. The rpoA and pheS gene similarities (99.0 to 99.2% and 94.3 to 95.4%, respectively) between E. viikkiensis and its closest phylogenetic neighbor, E. devriesei, were higher than those previously reported within the enterococci. In addition, the phenotypic profiles of the species in the E. avium group were also highly similar, and some traits were found to be misleading for enterococci, such as E. viikkiensis does not grow at 45°C. The numerical analysis of combined HindIII and EcoRI ribopatterns was of considerable assistance in distinguishing enterococcal species within the E. avium group.
在之前两项关于经改良气氛包装（MAP）包装的肉鸡产品和肉鸡加工厂中的乳酸菌（LAB）的研究中，有一些分离株仍然无法鉴定。根据 16S rRNA 基因序列分析，36 个分离株被分配到肠球菌属。这些分离株的 HindIII 和 EcoRI 核糖体图谱组合的数值分析导致形成了与通过 DNA 指导的 RNA 聚合酶亚基 A（rpoA）和苯丙氨酸-tRNA 合成酶α链（pheS）看家基因分析获得的聚类一致的种特异性聚类。在分析中，一组与任何已知肠球菌种都不同的五个分离株聚集在一起。这五个分离株位于肠球菌天蓝色亚种群中，与肠球菌德氏亚种最为接近。与肠球菌德氏亚种的 DNA-DNA 杂交水平在 28.8%至 54.3%之间，表明这些菌株代表了一个新的种。提议将其命名为viikkiensis 肠球菌新种，DSM 24043(T)（LMG 26075(T)）株为模式株。我们的研究表明，在肠球菌天蓝色亚种群内鉴定肠球菌需要多相分类学方法。与最接近的亲缘种肠球菌德氏亚种相比，viikkiensis 肠球菌的 rpoA 和 pheS 基因相似性（分别为 99.0%至 99.2%和 94.3%至 95.4%）高于肠球菌内先前报道的相似性。此外，肠球菌天蓝色亚种群内的种的表型谱也非常相似，一些特征被发现对肠球菌具有误导性，例如，viikkiensis 肠球菌不能在 45°C 下生长。组合 HindIII 和 EcoRI 核糖体图谱的数值分析对于区分肠球菌天蓝色亚种群内的肠球菌种具有重要帮助。
