發(fā)布者：抗性基因網(wǎng) 時(shí)間：2023-06-12 瀏覽量：592
摘要
? ? ? 對(duì)甲氧芐啶的耐藥性主要是通過(guò)獲得可移動(dòng)的dfrA基因介導(dǎo)的，其中大多數(shù)是在腸桿菌中發(fā)現(xiàn)的。2014年至2020年，共從中國(guó)不同農(nóng)場(chǎng)采集了139株鴨疫里默氏菌分離株。鴨疫病毒分離株的全基因組測(cè)序（WGS）和基因組分析顯示，有一個(gè)504bp的開(kāi)放閱讀框（ORF）編碼一個(gè)推定的dfrA基因。該DfrA變體與DfrA36具有66.47%的氨基酸序列同一性，與任何其他先前鑒定的DfrA蛋白具有≤51.20%的同一性。新的dfrA基因被命名為dfrA49，當(dāng)被克隆到大腸桿菌BL21（DE3）中時(shí)，賦予了甲氧芐啶（TMP）抗性。從江蘇和廣東省分離到30株dfrA49陽(yáng)性菌株（分別為5/38，13.16%和25/101，24.75%）。38個(gè)分離株中有5個(gè)獲得了完整的基因組序列。基因組分析顯示，dfrA49基因位于染色體或質(zhì)粒上（其中四個(gè)位于染色體上，一個(gè)位于質(zhì)粒上）。質(zhì)粒p20190305E2-2_2攜帶dfrA49、catB、ermF、ereD、blaOXA（與blaOXA-29的同一性為88.36%）、Δarr和tet（X18）。進(jìn)一步的研究表明，鴨疫霉中dfrA49通常與catB共存。在本研究中，利用WGS和生物信息學(xué)方法，在鴨疫霉的染色體和質(zhì)粒序列中鑒定并表征了一個(gè)新的甲氧芐啶抗性基因dfrA49。它進(jìn)一步擴(kuò)展了對(duì)甲氧芐啶產(chǎn)生耐藥性的可移動(dòng)dfrA基因庫(kù)的知識(shí)，并提供了關(guān)于鴨疫霉抗生素耐藥性基因的信息，在鴨疫霉中，耐藥性基因庫(kù)的循環(huán)尚不清楚。
ABSTRACT
Resistance to trimethoprim is mainly mediated by the acquisition of mobile dfrA genes, and most of them were discovered in Enterobacteriales. A total of 139 Riemerella anatipestifer isolates were collected from different farms in China during 2014 to 2020. Whole genome sequencing (WGS) and genome analysis of R. anatipestifer isolates revealed a 504-bp open reading frame (ORF) encoding a putative dfrA gene. This DfrA variant shared 66.47% amino acid sequence identity with DfrA36 and shared ≤51.20% identity with any other previously identified DfrA proteins. The novel dfrA gene, designated dfrA49, conferred trimethoprim (TMP) resistance when cloned into Escherichia coli BL21(DE3). Thirty dfrA49-positive isolates were identified from Jiangsu and Guangdong province (5/38, 13.16%, and 25/101, 24.75%, respectively). Five of the 38 isolates had obtained the complete genome sequences. Genomic analysis showed that the dfrA49 gene was located on chromosomes or a plasmid (four of them were on chromosomes and one was located on a plasmid). The plasmid p20190305E2-2_2 carried dfrA49, catB, ermF, ereD, blaOXA (88.36% identity with blaOXA-209), Δarr, and tet(X18). Further research indicated that dfrA49 usually coexisted with catB in R. anatipestifer. In this study, a novel trimethoprim resistance gene, dfrA49, was identified and characterized in chromosome and plasmid sequences from R. anatipestifer using WGS and bioinformatic methods. It further expands knowledge about the pool of mobile dfrA genes that confer resistance to trimethoprim and provides information about antibiotic resistance genes in R. anatipestifer, where the resistance gene pool circulating is not well understood.
https://journals.asm.org/doi/full/10.1128/spectrum.04747-22