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目的比较志贺菌耐药信息与其spacer同源质粒或噬菌体耐药信息的关系。方法应用CRISPR Target和BLAST寻找spacer同源质粒和噬菌体,根据登记号在NCBI或GenBank中寻找目标质粒或噬菌体上的耐药信息;应用Bioedit软件寻找GenBank中志贺菌的的耐药信息。结果数据库及临床分离株志贺菌共52条spacer中有7个spacer与4个携带耐药基因的质粒同源;间隔序列CRISPR2-mel-3同源质粒pUMNF18_IncFV及携带该间隔序列的志贺菌mel-ss1998011/zz、mel-ss1998024/zz、mel-sf2005082/sx、mel-sf2013004/bj均含有相同耐药基因blaTEM、aadA2和dfrA12,间隔序列CRISPR-Q1-S1、CRISPR-Q4-S1同源的质粒pM5A24P及该间隔序列所在志贺菌sd1012均携带耐药基因ampC和tetB;间隔序列CRISPR3-mel-33同源质粒plasmid:5与该间隔序列所在志贺菌mel-sf2000102/zz均携带相同耐药基因ampH、mrdA,且二者均携带毒力相关基因yafO、yafN、virK、ldrB、ychO。该质粒上还存在I-F型CRISPR/Cas系统。结论志贺菌spacer同源质粒与该菌耐药信息分布存在相似性;CRISPR可能对志贺菌的耐药和毒力实现共调控。因此推测在最初前间隔序列整合到CRISPR基因座形成一个新的间隔序列的过程中,志贺菌可能将携带前间隔序列外源遗传物质的其他基因片段如耐药基因和毒力基因也整合到志贺菌基因组中,影响其生存及性状。
Objective To compare the resistance of Shigella to its spacer homologous plasmid or phage resistance information. Methods CRISPR Target and BLAST were used to search for spacer homologous plasmids and phage. According to the accession numbers, the target plasmids or phage were searched for in NCBI or GenBank. Bioedit software was used to search for the drug resistance of Shigella in GenBank. Results Database and clinical isolates Shigella has a total of 52 out of 52 spacer, which is homologous to four plasmids carrying the resistance gene. The homologous plasmid pUMNF18_IncFV with the spacer sequence CRISPR2-mel-3 and Shigella mel-ss1998024 / zz, mel-sf2005082 / sx and mel-sf2013004 / bj all contain the same drug resistance genes blaTEM, aadA2 and dfrA12, the homology of CRISPR-Q1-S1 and CRISPR-Q4-S1 Of the plasmid pM5A24P and Shigella sd1012 where the spacer sequence carries the resistance genes ampC and tetB; the spacer sequence CRISPR3-mel-33 homologous plasmid plasmid: 5 carries the same sequence as the Shigella mel-sf2000102 / zz Resistance genes ampH, mrdA, and both carry virulence related genes yafO, yafN, virK, ldrB, ychO. This plasmid also has a type I-F CRISPR / Cas system. Conclusion The homology of Shigella spacer homology plasmid and the drug resistance distribution of this strain are similar. CRISPR may co-regulate the resistance and virulence of Shigella. Therefore, it is hypothesized that Shigella may also integrate other gene fragments carrying exogenous genetic elements of the pre-spacer sequence, such as drug resistance genes and virulence genes, in the process of integrating the initial pre-spacer sequence into the CRISPR locus to form a new spacer sequence Shigella genome, affecting its survival and traits.