{"title":"Insertion with long target duplication in polymyxin B-induced resistant mutant of Salmonella","authors":"","doi":"10.1016/j.jgar.2024.07.002","DOIUrl":null,"url":null,"abstract":"<div><h3>Objectives</h3><p>A <em>Salmonella enterica</em> subsp. <em>diarizonae</em> (hereafter <em>S. diarizonae</em>) clinical strain S499 demonstrated unique genomic features. The strain S499 was treated with polymyxin B in vitro to investigate the mechanism of resistance.</p></div><div><h3>Methods</h3><p>S499 was treated with polymyxin B by increasing concentration gradually to obtain a resistant mutant S499V. Whole genomes of the two strains were sequenced using Illumina HiSeq X<strong>-</strong>10 and PacBio RS II platforms. Reverse transcription–quantitative polymerase chain reaction (RT-qPCR) was performed to compare the gene expression.</p></div><div><h3>Results</h3><p>The chromosome of strain S499 contained a 40-kb DNA region that was replicated after treatment with polymyxin B and generated a triple tandem DNA repeat region in the chromosome of mutant strain S499V. This repeat region in S499V was flanked by IS<em>1</em> and contained <em>pmrD, pmrG</em>, and <em>arnBCADTEF</em> operon<em>.</em> In comparison to the homologous 40-kb DNA region of strain S499, a few genes in the repeat DNA region of strain S499V contained truncating mutations that generate two open reading frames (ORFs). The expression of <em>pmrD, pmrG</em>, and <em>arnT</em> was significantly upregulated in S499V.</p></div><div><h3>Conclusion</h3><p>The duplication and overexpression of <em>pmrD, pmrG</em>, and <em>arnT</em> operon may be responsible for the polymyxin B resistance of mutant strain S499V.</p></div>","PeriodicalId":15936,"journal":{"name":"Journal of global antimicrobial resistance","volume":null,"pages":null},"PeriodicalIF":3.7000,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213716524001334/pdfft?md5=b614bd4747185be867b00655dbb4f751&pid=1-s2.0-S2213716524001334-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of global antimicrobial resistance","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2213716524001334","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"INFECTIOUS DISEASES","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives
A Salmonella enterica subsp. diarizonae (hereafter S. diarizonae) clinical strain S499 demonstrated unique genomic features. The strain S499 was treated with polymyxin B in vitro to investigate the mechanism of resistance.
Methods
S499 was treated with polymyxin B by increasing concentration gradually to obtain a resistant mutant S499V. Whole genomes of the two strains were sequenced using Illumina HiSeq X-10 and PacBio RS II platforms. Reverse transcription–quantitative polymerase chain reaction (RT-qPCR) was performed to compare the gene expression.
Results
The chromosome of strain S499 contained a 40-kb DNA region that was replicated after treatment with polymyxin B and generated a triple tandem DNA repeat region in the chromosome of mutant strain S499V. This repeat region in S499V was flanked by IS1 and contained pmrD, pmrG, and arnBCADTEF operon. In comparison to the homologous 40-kb DNA region of strain S499, a few genes in the repeat DNA region of strain S499V contained truncating mutations that generate two open reading frames (ORFs). The expression of pmrD, pmrG, and arnT was significantly upregulated in S499V.
Conclusion
The duplication and overexpression of pmrD, pmrG, and arnT operon may be responsible for the polymyxin B resistance of mutant strain S499V.
期刊介绍:
The Journal of Global Antimicrobial Resistance (JGAR) is a quarterly online journal run by an international Editorial Board that focuses on the global spread of antibiotic-resistant microbes.
JGAR is a dedicated journal for all professionals working in research, health care, the environment and animal infection control, aiming to track the resistance threat worldwide and provides a single voice devoted to antimicrobial resistance (AMR).
Featuring peer-reviewed and up to date research articles, reviews, short notes and hot topics JGAR covers the key topics related to antibacterial, antiviral, antifungal and antiparasitic resistance.