目的探讨454高通量测序平台应用于临床样本快速检测的可能性。方法应用454高通量测序平台测定血液、呼吸道和消化道临床样本中微生物菌群的16S r DNA基因的V3-V4高变异区段序列,采用BLAST方法与RDP数据库进行比对,基于比对结果,获得不同种属的病原菌的所匹配的read数。结果 8份临床模拟样本中,7份检测出目标菌属,检出率为87.5%。在血液、肺泡灌洗液和咽拭子这类正常状态下的无菌体液,检测结果较为明确,检出的细菌较为集中,显示了检测结果的可靠性。而对本身含有较多种类细菌的粪便样本,其目标菌比例明显降低。结论实现了80 h内得到血液、呼吸道和消化道临床样本中含有病原菌情况的检测报告,并探讨了高通量测序技术在今后临床实际应用时进一步提高检测速度和灵敏度的方法。
Secretion systems, macromolecules to pass which can mediate the across cellular membranes, are essential for virulent and genetic material exchange among bacterial species[1]. Type IV secretion system （T4SS） is one of the secretion systems and it usually consists of 12 genes： VirB1, VirB2 ...VirB11, and VirD4[2]. The structure and molecular mechanisms of these genes have been well analyzed in Gram-negative strains[3] and Gram-positive strains were once believed to be lack of T4SS. However, some recent studies revealed that one or more virB/D genes also exist in some kinds of Gram-positive bacteria and play similar role, and form a T4SS-like system[3]. The VirBl-like, VirB4, VirB6, and VirD4 genes were identified in the chromosome of Gram-positive bacterium Streptococcus suis in our previous studies and their role as important mobile elements for horizontal transfer to recipients in an 89 K pathogenicity island （PAl） was demonstrated[45]. However, their structure and molecular mechanisms in other strains, especially in Gram-positive strains, are remained unclear.
ZHANG WenYU Wei WenLIU DiLI MingDU Peng ChengWU Yi LeiGeorge F. GAOCHEN Chen
