Molecular analysis of antibiotic resistance gene clusters in Vibrio cholerae O139 and O1SXT constins
Molecular analysis of antibiotic resistance gene clusters in Vibrio cholerae O139 and O1SXT constins
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DOI：
10.1128/aac.45.11.2991-3000.2001
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发表时间：
2001-11-01
影响因子：
4.9
通讯作者：
Waldor, MK
中科院分区：
文献类型：
--
作者：
Hochhut, B;Lotfi, Y;Waldor, MK
许多最近的亚洲临床霍乱弧菌El Tor O1和O139分离株对抗生素磺胺甲恶唑（Su）、甲氧苄啶（Tm）、氯霉素（Cm）和链霉素（Sm）具有耐药性。相应的抗性基因位于整合到霍乱弧菌染色体上的prfC中的大接合元件（SXT constins）上。我们测定了O139分离株MO10的SXT constin中抗生素抗性基因的DNA序列。在SXTMO10中，这些基因聚集在元件5'端附近发现的复合转座子样结构内。赋予对Cm（floR）、So（sul II）和Sm（strA和strB）的抗性的基因对应于先前描述的基因，而赋予对Tm的抗性的基因，命名为dfr 18，是新的。在其他O139分离株中，抗生素抗性基因簇被发现从SXT相关的constin中缺失。El Tor O1 SXT constin（SXT ET）不含与SXTMO 10相同的抗性基因。Tin抗性决定簇位于一种新的整合子中，与其它抗性基因相距约70 kbp，构成第四类抗性整合子。这些研究表明，有相当大的流量中发现的抗生素耐药基因的SXT家族的constins和点的进化模型，这些相关的移动的元素。
Many recent Asian clinical Vibrio cholerae El Tor O1 and O139 isolates are resistant to the antibiotics sulfamethoxazole (Su), trimethoprim (Tm), chloramphenicol (Cm), and streptomycin (Sm). The corresponding resistance genes are located on large conjugative elements (SXT constins) that are integrated into prfC on the V. cholerae chromosome. We determined the DNA sequences of the antibiotic resistance genes in the SXT constin in MO10, an O139 isolate. In SXTMO10, these genes are clustered within a composite transposon-like structure found near the element's 5' end. The genes conferring resistance to Cm (floR), So (sulII), and Sm (strA and strB) correspond to previously described genes, whereas the gene conferring resistance to Tm, designated dfr18, is novel. In some other O139 isolates the antibiotic resistance gene cluster was found to be deleted from the SXT-related constin. The El Tor O1 SXT constin, SXT ET, does not contain the same resistance genes as SXTMO10. In this constin, the Tin resistance determinant was located nearly 70 kbp away from the other resistance genes and found in a novel type of integron that constitutes a fourth class of resistance integrons. These studies indicate that there is considerable flux in the antibiotic resistance genes found in the SXT family of constins and point to a model for the evolution of these related mobile elements.