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上传于 2019-3-26 05:41 (167 KB)

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JANEWANGJK55 发表了评论   2019-5-30 22:09
It seems likely that complex dissemination of mcr-like genes relies on the diffusion of promiscuous plasmids, rather than on the clonal expansion of mcr-1-bearing bacteria.  Although the prevalence of particular plasmids may vary depending on the source and geographical site, they have been increasingly isolated from bacteria of human, animal and environmental origin, highlighting the frequent exchange of genetic material between different niches.
JANEWANGJK55 发表了评论   2019-5-30 22:12
The companion animal carrying the mcr-1 isolate in this study was from an urban area of Tianjin, so it had minimal or no contact with food-producing animals in which colistin may have been used.  Thus sick pets may contribute to the pool of clinically relevant antibiotic-resistant bacteria (Hartantyo et al., 2018) and transmit colistin-resistant to Enterobacteriaceae.
JANEWANGJK55 发表了评论   2019-5-31 22:17
The latter was located in a typical ISEcp1-blaCTX-M-55 transposition unit.  BLASTn comparison of the plasmid pCQ9-4 with plasmids pHNSHP45 and pA31-12 revealed a 99% similarity (88% query coverage) and a 99% similarity (90% query coverage).
JANEWANGJK55 发表了评论   2019-6-1 01:24
All mcr-1-harboring isolates were belonged to different multilocus sequence types (MLST) and harbored diverse blaESBL genes (blaCTX-M-24/27/55/64).
JANEWANGJK55 发表了评论   2019-6-1 11:06
The colocalization of mcr-1 with an ESBL gene on a conjugative plasmid may accelerate the dissemination of both genes by coselection.

co-resistant isolates could be detected along the food chain (food-producing animals, companion animals and food) increasing the risk to humans arising from transmission of foodborne/zoonotic resistant bacteria.   ***may provide insight into the distinct manner of their transmission/dissemination; hence, further studies on the epidemiology and microbiology of these strains are needed.
Interventions are necessary to minimise further dissemination of mcr-1, which would limit the future usefulness of colistin as a last-resort antibiotic. We found two ESBL and mcr-1 coproducing plasmids.

The co-selection aspect may contribute to a further spread of these mcr-1-bearing plasmids and future study on this phenomenon is necessary to aid in determining effective antibiotic treatment protocols and for assessing the risks of antibiotic use.

It is notable that all the isolates transferred the colistin resistance marker to the recipient with high transfer rates. It is notable that the cafotaxime could select the mcr-1-harbouring plasmid, IncI2. …… In contrast, …….

It is noteworthy that this is the first description of ….
The colocalization of mcr-1 with an ESBL gene on a conjugative plasmid may accelerate the dissemination of both genes by coselection.
Indicating a complex evolutionary process for these IncI2 plasmids carrying mcr-1.
This situation could give rise to the co-selection, promoting the dissemination of ESBL-genotypes among bacteria of healthy food-producing animal and human origins alike.
JANEWANGJK55 发表了回复   2022-6-22 10:09
围绕对我国畜牧业养殖危害巨大的致病菌进行其耐药性与致病毒力等方面的研究,开展了耐药基因的传播机制及致病菌的诊断防治技术等基础前沿研究,取得了重要创新成果。
(1)研究发现替加环素耐药基因tet(X4)在大肠杆菌中主要由IncX1型质粒传播,并且不同质粒和细菌染色体中有相似的核心遗传结构abh-tet(X4)-ISCR2和ISCR2-abh-tet(X4)-ISCR2。通过对不动杆菌中tet(X3)基因环境的分析发现其核心遗传结构为IS26-xerD-tet(X3)-resolvase-hp-ISCR2,并通过实验证实插入元件 IS26 也可以形成环状中间体,以促进tet(X3)在细菌间传播。(2)首次分析了西部四省(陕西,宁夏,青海和内蒙古)在不同饲养条件下(集约化养殖和放牧),羊源耐药性大肠杆菌的流行与传播情况,集约化饲养的绵羊大肠杆菌耐药性高于放牧模式下分离的菌株,另外发现etrA为最常见毒力基因。(3)本团队于2021年在陕西、甘肃、青海、宁夏和新疆分离产气荚膜梭菌约50株左右。通过比较青海省放牧羊和甘肃省集约化饲养绵羊产气荚膜梭菌生物特征不同,发现1株生长速度较快和溶血能力较强产气荚膜梭菌,并首次发现噁唑烷酮类耐药基因optrA,正在进行相关新型高效疫苗研究。

主持国家自然科学基金、中国博士后基金特别资助、陕西省自然科学基金、中国博士后面上项目、陕西省博士后特别资助等国家和省部级科研项目十余项。以第一或通讯作者在VM等权威期刊发表SCI论文近30篇。参与撰写农业行业标准《伪结核棒状杆菌的分离鉴定》一项,参与“国家动物源(羊源)细菌耐药性监测计划”和“陕西省农业专项资金项目—山羊伪结核病的防控技术”等国家和省级重大羊病防控项目。2021年4月起被委任为陕西省病原微生物实验室生物安全专家委员会委员。协助指导的博士生获国家奖学金,协助指导的硕士生获校级优秀硕士学位论文。

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