Class 1 integrons lacking qacEΔ1 and sul1 genes in Escherichia coli isolates of food, animal and human origins
Class 1 integrons lacking qacEΔ1 and sul1 genes in Escherichia coli isolates of food, animal and human origins
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DOI：
10.1016/j.vetmic.2010.01.026
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发表时间：
2010-08-26
影响因子：
3.3
通讯作者：
Torres, C.
中科院分区：
文献类型：
--
作者：
Saenz, Y.;Vinue, L.;Torres, C.
目的：目的研究不同来源的intl 1阳性大肠杆菌中缺失3 '端保守片段（CS）的1类整合子的频率和多样性。方法：在84例大肠杆菌中检测到intl 1的存在。来源于食物（21株）、动物（32株）和健康人志愿者（31株）的大肠杆菌分离株。通过PCR分析qacE Delta 1-sul 1基因，并将缺乏这些基因的分离株纳入本工作。用PCR和测序引物步移法确定1类整合子的遗传结构。结果：在84株intl 1阳性的大肠杆菌中，有13株存在缺失3 '-CS的1类整合子。大肠杆菌分离株（15.5%）的食物，动物和人类的起源。所有13株分离株显示不相关模式的REP-PCR。在这13个菌株的1类整合子内鉴定了以下基因盒排列：dfrA 1; dfrA 5; dfrA 1 2-orfF-aadA 2-cmlA 1-aadA 1-qacH-IS 440-sul 3; dfrA 1 2-orjF-aadA 2-cmlA 1-aadA 1 - 1 S440-sul 3; estX-psp-aadA 2-cmlA 1-aadA 1-qacH-1 S440-sul 3;以及一种新的排列estX-psp-aadA 2-cmlA 1 Delta-1 S1294-Delta cmlA 1-aadA 1-qacH-IS 440-sul 3，其将IS 1294插入cmlA 1基因（包括在GenBank中，编号为EU 704128）。在该型整合子中，在sul 3基因上游检测到完整或截短的mef（B）基因。通过PCR-复制子分型，检测IncY、I1、FIC、FIB、FIB质粒的不同组合，在所研究的四个菌株中鉴定质粒。结论：intl 1阳性大肠杆菌中存在缺失3 '-CS的1类整合子，且整合子的多样性较高。不同来源的大肠埃希菌分离株相对较高。在大多数缺失3 '-CS的1类整合子中检测到sul 3基因。(C)2010 Elsevier B. V.保留所有权利。
Objectives: To study the frequency and diversity of class 1 integrons lacking the 3'-conserved segment (CS) in intl1-positive Escherichia coli isolates of different origins. Methods: The presence of intl1 was previously detected in 84 E. coli isolates of food (21 isolates), animal (32) and healthy-human volunteer (31) origins. The qacE Delta 1-sul1 genes were analyzed by PCR and those isolates that lacked these genes were included in this work. The genetic structure of class 1 integrons was determined, using the PCR and sequencing primer-walking strategy. Isolates and plasmids were typed.Results: Class 1 integrons lacking the 3'-CS were found in 13 of the 84 intl1-positive E. coli isolates (15.5%) of food, animal, and human origins. All 13 isolates showed unrelated patterns by REP-PCR. The following gene cassette arrangements were identified inside the class 1 integrons of these 13 strains: dfrA1; dfrA5; dfrAl2-orfF-aadA2-cmlA1-aadA1-qacH-IS440-sul3; dfrAl2-orjF-aadA2-cm1A1-aadA1-1S440-sul3; estX-psp-aadA2-cmlA1-aadA1-qacH-1S440-sul3; and a new arrangement estX-psp-aadA2-cmlA1 Delta-1S1294-Delta cm1A1-aadA1-qacH-IS440-sul3 that contain the IS 1294 into the cmlA1 gene (included in GenBank, number EU704128). Complete or truncated mef(B) gene was detected upstream of sul3 gene in this type of integrons. Plasmids were identified in four of the studied strains by PCR-replicon-typing, detecting different combinations of IncY, I1, FIC, FII, FIB plasmids. Non-classic integrons were located into plasmids of 100-150 kb in four studied strains.Conclusions: Occurrence and diversity of class 1 integrons lacking 3'-CS among the studied intl1-positive E. coli isolates of different origins were relatively high. The sul3 gene was detected in most of class 1 integrons lacking 3'-CS. (C) 2010 Elsevier B.V. All rights reserved.