Christensen H, Møller P L, Vogensen F K, Olsen J E
Department of Veterinary Microbiology, and Centre for Advanced Food Studies, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark.
Res Microbiol. 2000 Jan-Feb;151(1):37-42. doi: 10.1016/s0923-2508(00)00129-7.
The possibility for identification of Salmonella enterica serotypes by sequence analysis of the 16S to 23S rRNA internal transcribed spacer was investigated by direct sequencing of polymerase chain reaction-amplified DNA from all operons simultaneously in a collection of 25 strains of 18 different serotypes of S. enterica, and by sequencing individual cloned operons from a single strain. It was only possible to determine the first 117 bases upstream from the 23S rRNA gene by direct sequencing because of variation between the rrn operons. Comparison of sequences from this region allowed separation of only 15 out of the 18 serotypes investigated and was not specific even at the subspecies level of S. enterica. To determine the differences between internal transcribed spacers in more detail, the individual rrn operons of strain JEO 197, serotype IV 43:z4,z23:-, were cloned and sequenced. The strain contained four short internal transcribed spacer fragments of 382-384 bases in length, which were 98.4-99.7% similar to each other and three long fragments of 505 bases with 98.0-99.8% similarity. The study demonstrated a higher degree of interbacterial variation than intrabacterial variation between operons for serotypes of S. enterica.
通过对来自18种不同血清型的25株肠炎沙门氏菌同时进行聚合酶链反应扩增DNA的所有操纵子的直接测序，以及对单一菌株的单个克隆操纵子进行测序，研究了通过16S至23S rRNA内部转录间隔区的序列分析来鉴定肠炎沙门氏菌血清型的可能性。由于rrn操纵子之间存在差异，通过直接测序仅能确定23S rRNA基因上游的前117个碱基。对该区域序列的比较仅能区分所研究的18种血清型中的15种，甚至在肠炎沙门氏菌亚种水平上也不具有特异性。为了更详细地确定内部转录间隔区之间的差异，对血清型IV 43:z4,z23:-的JEO 197菌株的单个rrn操纵子进行了克隆和测序。该菌株包含四个长度为382 - 384个碱基的短内部转录间隔区片段，它们彼此之间的相似性为98.4 - 99.7%，以及三个长度为505个碱基、相似性为98.0 - 99.8%的长片段。该研究表明，肠炎沙门氏菌血清型的操纵子之间，细菌间变异程度高于细菌内变异程度。
