Proteus mirabilis clinical isolate harbouring a new variant of Salmonella genomic island 1 containing the multiple antibiotic resistance region
Proteus mirabilis clinical isolate harbouring a new variant of Salmonella genomic island 1 containing the multiple antibiotic resistance region
复制标题
DOI：
10.1093/jac/dkl471
复制
发表时间：
2007-02-01
影响因子：
5.2
通讯作者：
Shimamoto, Tadashi
中科院分区：
文献类型：
--
作者：
Ahmed, Ashraf M.;Hussein, Amjad I. A.;Shimamoto, Tadashi
目的：检测一株具有沙门氏菌基因组岛1多药耐药表型的奇异变形杆菌18306株临床分离株是否存在该岛及其多重耐药区。方法：奇异变形杆菌18306株是2006年3月从巴勒斯坦一例糖尿病足感染患者中分离到的。结果：奇异假单胞菌18306对氨苄西林、氯霉素、链霉素、磺胺类和四环素耐药，对甲氧苄氨嘧啶和奈立地酸耐药，表现出典型的多重耐药表型。分子鉴定表明，奇异假单胞菌18306具有与SGI1相似的结构，不同之处在于标准SGI1的抗链霉素和壮观霉素的aadA2基因已被耐甲氧氨嘧啶的dfrA15所取代。此外，奇异沙门氏菌SGI1的染色体外环状结构与鼠伤寒沙门氏菌DT104的核苷酸序列完全相同。然而，聚合酶链式反应结果表明，奇异P.mirabilis 18306的左右两个连接处均为阴性，这代表了SGI1整合到肠沙门氏菌染色体上的位置。因此，这个新的SGI1变异体可能在不同的位置整合到奇异拟青霉18306的染色体上。在该菌株中还发现了TN 1826衍生的2类整合子，它只携带SAT2和AADA 1两个基因盒。结论：在本研究中，我们在一株多药耐药株中发现了一个新的含有多重耐药基因组区域的SGI1变异株。这是在沙门氏菌以外的属中首次发现SGI1。
Objectives: A clinical isolate of Proteus mirabilis strain 18306, which displayed the multidrug resistance phenotype of Salmonella genomic island 1 (SGI1), was examined for the presence of this island including its multiple antibiotic resistance genomic region.Methods: P. mirabilis 18306 was isolated in March 2006 from a patient in Palestine with diabetic foot infection. Antibiotic susceptibility tests and various molecular techniques, including PCR, cloning and DNA sequencing were used for detection and characterization of SGI1 in P. mirabilis 18306.Results: P. mirabilis 18306 showed the typical multidrug resistance phenotype of SGI1 as it was resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracycline, in addition to trimethoprim and nalidixic acid. Molecular characterization showed that P. mirabilis 18306 harboured a structure similar to SGI1, except that the aadA2 gene, which confers resistance to streptomycin and spectinomycin, of standard SGI1 had been replaced with dfrA15, which confers resistance to trimethoprim. Furthermore, the nucleotide sequence of the extrachromosomal circular form of SGI1 in P. mirabilis was found to be identical to that of Salmonella Typhimurium DT104. However, PCR results showed that P. mirabilis 18306 was negative for the left and right junctions which represent the integration sites of SGI1 into Salmonella enterica chromosome. Hence, this new variant of SGI1 may be integrated at a different site into the chromosome of P. mirabilis 18306. Tn 1826-derived class 2 integron, which carries only two gene cassettes, sat2 and aadA 1, was also identified in this strain.Conclusions: In this study, we identified a new variant SGI1 containing the multiple resistance genomic region in a multidrug-resistant strain of P. mirabilis. This is the first report for SGI1 in a genus other than Salmonella.