Bergman S, Selig M, Collins M D, Farrow J A, Baron E J, Dickersin G R, Ruoff K L
Pathology Department, Massachusetts General Hospital, Boston 02114, USA.
Int J Syst Bacteriol. 1995 Apr;45(2):235-9. doi: 10.1099/00207713-45-2-235.
Isolates belonging to the "Streptococcus milleri" species group that appear to exhibit a gliding type of motility, which is expressed as spreading growth on certain types of agar media, are described. These strains resembled a biotype of "S. milleri" that is usually isolated from genitourinary sources and is notable for its ability to ferment a wide array of carbohydrates. This biotype, which is currently included in the species Streptococcus anginosus, has been implicated in cases of neonatal infection. The "S. milleri" isolates which we studied lacked any observable organelles of motility and gave negative results when they were tested in conventional motility test medium stab cultures. Colonies growing on certain agar media, however, spread over the surfaces of plates and increased in area with increasing time of incubation. Chocolate agar supported maximum spreading, while this characteristic was barely discernible on blood agar. Electron microscopy studies revealed that there was more production of extracellular glycocalyx by motile strains than by a nonmotile isolate having a similar biotype. The results of an analysis of 16S rRNA gene sequences suggested that the motile strains are closely related to S. anginosus and represent a distinct rRNA population within the "S. milleri" species complex.
本文描述了属于“米勒链球菌”种组的分离株，这些分离株似乎表现出一种滑动型运动性，在某些类型的琼脂培养基上表现为扩散生长。这些菌株类似于“米勒链球菌”的一个生物型，通常从泌尿生殖系统来源分离得到，以其发酵多种碳水化合物的能力而闻名。这种目前归入咽峡炎链球菌种的生物型，已涉及新生儿感染病例。我们研究的“米勒链球菌”分离株缺乏任何可观察到的运动细胞器，在传统的运动性测试培养基穿刺培养中进行测试时结果为阴性。然而，在某些琼脂培养基上生长的菌落会扩散到平板表面，并随着培养时间的增加而扩大面积。巧克力琼脂支持最大程度的扩散，而在血琼脂上这种特征几乎难以辨别。电子显微镜研究表明，与具有相似生物型的非运动性分离株相比，运动性菌株产生的细胞外糖萼更多。16S rRNA基因序列分析结果表明，运动性菌株与咽峡炎链球菌密切相关，代表了“米勒链球菌”种复合体中的一个独特rRNA群体。
