Liu Chih-Chin, Kuo Han-Yueh, Tang Chuan Yi, Chang Kai-Chih, Liou Ming-Li
Department of Bioinformatics, Chung Hua University, Hsin-Chu City, Taiwan; Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan.
Department of Medicine, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu City, Taiwan; School of Medicine, National Taiwan University, Taipei City, Taiwan.
Genomics. 2014 Sep;104(3):215-23. doi: 10.1016/j.ygeno.2014.07.011. Epub 2014 Jul 27.
We investigated the prevalence of a type IV secretion system (T4SS)-bearing plasmid among clinical isolates of carbapenem-resistant Acinetobacter baumannii (CRAB) using plasmid replicon typing. The complete sequence of a T4SS-bearing plasmid, pAB_CC, isolated from A. baumannii TYTH-1 was determined, and a comparative analysis of the T4SS gene modules was performed. Of the 129 isolates studied, GR6 (repAci6) was the most common (45 of 96 isolates) and was strongly linked with the T4SS. A comparative analysis of the T4SS locus in seven plasmid genomes, including pAB_CC, pACICU2, pABKp1, pABTJ1, p1BJAB0714, p2BJAB0868, and p2ABTCDC0715, indicated that fourteen genes on these plasmids were highly conserved compared to those of the F plasmid. Additionally, the chromosomes in the seven representative isolates may be evolutionarily distinct from their intrinsic T4SS-bearing plasmids, suggesting that the two T4SS lineages emerged long before the appearance of EC II. These two lineages are now widespread in A. baumannii strains.
我们使用质粒复制子分型方法，调查了耐碳青霉烯鲍曼不动杆菌（CRAB）临床分离株中携带IV型分泌系统（T4SS）质粒的流行情况。测定了从鲍曼不动杆菌TYTH-1分离出的携带T4SS的质粒pAB_CC的完整序列，并对T4SS基因模块进行了比较分析。在所研究的129株分离株中，GR6（repAci6）最为常见（96株中有45株），且与T4SS密切相关。对包括pAB_CC、pACICU2、pABKp1、pABTJ1、p1BJAB0714、p2BJAB0868和p2ABTCDC0715在内的七个质粒基因组中的T4SS位点进行比较分析，结果表明，与F质粒相比，这些质粒上的14个基因高度保守。此外，七个代表性分离株中的染色体在进化上可能与其内在的携带T4SS的质粒不同，这表明这两个T4SS谱系在EC II出现之前很久就已出现。这两个谱系现在在鲍曼不动杆菌菌株中广泛存在。
