Deletion of luxS further attenuates the virulence of the avian pathogenic Escherichia coli aroA mutant
Deletion of luxS further attenuates the virulence of the avian pathogenic Escherichia coli aroA mutant
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luxS的缺失进一步减弱了禽类致病性大肠杆菌aroA突变体的毒力
DOI：
10.1016/j.micpath.2015.08.003
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发表时间：
2015-11-01
影响因子：
3.8
通讯作者：
Yu, Shengqing
中科院分区：
文献类型：
--
作者：
Han, Xiangan;Bai, Hao;Yu, Shengqing
本研究从禽致病性大肠杆菌（APEC）DE 17株出发，构建aroA缺失突变株（DE 17 Δ aroA）和aroA和/uxS双缺失APEC突变株（DE 17 Δ luxS Δ aroA）。结果表明，与DE 17 Δ aroA相比，DE 17 Δ luxS Δ aroA在雏鸭中的毒力分别进一步减弱了200倍和31.7倍，基于50%致死剂量。与野生型菌株DE 17相比，DE 17 Delta luxS Delta aroA和DE 17 Delta aroA的粘附和侵袭能力分别降低了36.5%/42.5%和25.8%/29.3%（分别为p < 0.05和0.01）。此外，体内研究表明，与野生型菌株DE 17相比，DE 17 Delta luxS Delta aroA的细菌载量在感染禽的脾脏和血液中分别减少了8400倍和11，333倍，而DE 17 Delta aroA的细菌载量分别减少了743倍和1000倍。组织学分析表明，突变体与鸭的肝、脾和肾的病理变化减少有关，并且DE 17 Delta luxS Delta aroA感染的鸭的变化比DE 17 Delta aroA感染的鸭减少的程度更大。实时聚合酶链反应分析进一步证明了毒力相关基因（即，tsh、ompA、vat、iucD、pfs、fyuA和fimC）在DE 17 Δ aroA中显著降低，尤其是在DE 17 Δ luxS Δ aroA中（p < 0.05）。为了评价DE 17 Δ luxS Δ aroA作为候选疫苗的潜在用途，将50只7日龄雏鸭随机分为5组，每组10只。结果表明，DE 17、DE 17 Δ luxS、DE 17 Δ aroA和DE 17 Δ luxS Δ aroA灭活疫苗免疫雏鸭的保护率分别为70.0%、70.0%、70.0%和80.0%;本研究结果表明，luxS和aroA的双缺失使APEC致病性减弱，DE 17 Δ luxS Δ aroA比DE 17 Δ aroA更适合于开发针对禽大肠杆菌病的未来疫苗。(C)2015爱思唯尔有限公司版权所有。
In this study, an aroA-deletion avian pathogenic Escherichia coli (APEC) mutant (strain DE17 Delta aroA) and aroA and /uxS double deletion APEC mutant (strain DE17 Delta luxS Delta aroA) were constructed from the APEC DE17 strain. The results showed that as compared to DE17 Delta aroA, the virulence of DE17 Delta luxS Delta aroA was further attenuated by 200- and 31.7-fold, respectively, in ducklings based on the 50% lethal dose. The adherence and invasion abilities of DE17 Delta luxS Delta aroA and DE17 Delta aroA were reduced by 36.5%/42.5% and 25.8%/29.3%, respectively, as compared to the wild-type strain DE17 (p < 0.05 and 0.01, respectively). Furthermore, in vivo studies showed that the bacterial loads of DE17 Delta luxS Delta aroA were reduced by 8400- and 11,333-fold in the spleen and blood of infected birds, respectively, while those of DE17 Delta aroA were reduced by 743- and 1000-fold, respectively, as compared to the wild-type strain DE17. Histopathological analysis showed both that the mutants were associated with reduced pathological changes in the liver, spleen, and kidney of ducklings, and changes in DE17 Delta luxS Delta aroA-infected ducklings were reduced to a greater degree than those infected with DE17 Delta aroA. Real-time polymerase chain reaction analysis further demonstrated that the mRNA levels of virulence-related genes (i.e., tsh, ompA, vat, iucD, pfs, fyuA, and fimC) were significantly decreased in DE17 Delta aroA, especially in DE17 Delta luxS Delta aroA, as compared to DE17 (p < 0.05). In addition, the deletion of aroA or the double deletion of aroA and luxS reduced bacterial motility.To evaluate the potential use of DE17 Delta luxS Delta aroA as a vaccine candidate, 50 7-day-old ducklings were divided randomly into five groups of ten each for the experiment. The results showed that the ducklings immunized with inactivated DE17, DE17 Delta luxS, DE17 Delta aroA, and DE17 Delta luxS Delta aroA were 70.0%, 70.0%, 70.0, and 80.0% protected, respectively, after challenge with strain APEC DE17.The results of this study suggest that the double deletion of luxS and aroA attenuated APEC pathogenicity and DE17 Delta luxS Delta aroA was more appropriate for development of a future vaccine against avian colibacillosis than DE17 Delta aroA. (C) 2015 Elsevier Ltd. All rights reserved.