健康人携带的沙门菌中沙门菌基因组岛1的鉴定及特性分析

Identification and characterization of Salmonella genomic island 1 among Salmonella strains from healthy persons

目的检测健康人携带的沙门菌中沙门菌基因组岛(SGI1)的分布情况及特性,分析其与细菌耐药性的关系。方法采用PCR方法对5株第一类整合子阳性的沙门菌检测SGI1,分别检测其左侧、右侧部分和其中间的部分基因,以及环状形式和切除状态,通过接合转移及自然转化检测其可移动性。结果一株鼠伤寒沙门菌携带SGI1,位于thdF和int2之间,且其多重耐药区含aadA2,floR,tetG,blaPSE-1基因,存在环状形式及切除状态,且可通过自然转化方式转移至其他菌株。结论 SGI1可通过自然转化方式转移到其他菌株,介导多重耐药的传播。

Objective To identify and characterize Salmonella genomic island 1 （SGII） in Salmonella strains--from healthy person, and to analyze the relationship between SGI1 and antibiotic resistance. Methods Five class 1 integron positive strains were tested for the presence of SGI1 with PCR method, and the positive amplicons were sequenced and analyzed. To detect the mobilization of the SGI1, the extrachromosome circle forms or the excision as well as conjugation and natural genetic transformation were examined. Results SGI1 was detected in a Salmonella enterica serovar Typhoid murine strain, with the aadA2, floR, tetG, and blapsE_l genes in its multidrug-resistant region, and it was located between thdF and a retronphage （int2）. Both the extrachromosome circle form of SGI1 and the excision of SGI1 were detected, and it could transfer through natural genetic transformation. Conclusion The presence of SGII in Salmonella strains from healthy person suggests that widespread surveillance of antibiotic resistance should be conducted at the gene level.