Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.

<h4>Background</h4>Nalidixic acid resistance among Salmonella Typhimurium clinical isolates has steadily increased, whereas the level of ciprofloxacin resistance remains low. The main objective of this study was to characterize the fluoroquinolone resistance mechanisms acquired in a S. T...

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Autores principales:	Anna Fàbrega, Laurence du Merle, Chantal Le Bouguénec, M Teresa Jiménez de Anta, Jordi Vila
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2009
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/f6800048a0f24bee9dcc6967f1516a0e
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spelling	oai:doaj.org-article:f6800048a0f24bee9dcc6967f1516a0e2021-11-25T06:27:48ZRepression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.1932-620310.1371/journal.pone.0008029https://doaj.org/article/f6800048a0f24bee9dcc6967f1516a0e2009-11-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19946377/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>Nalidixic acid resistance among Salmonella Typhimurium clinical isolates has steadily increased, whereas the level of ciprofloxacin resistance remains low. The main objective of this study was to characterize the fluoroquinolone resistance mechanisms acquired in a S. Typhimurium mutant selected with ciprofloxacin from a susceptible isolate and to investigate its invasion ability.<h4>Methodology/principal findings</h4>Three different amino acid substitutions were detected in the quinolone target proteins of the resistant mutant (MIC of ciprofloxacin, 64 microg/ml): D87G and G81C in GyrA, and a novel mutation, E470K, in ParE. A protein analysis revealed an increased expression of AcrAB/TolC and decreased expression of OmpC. Sequencing of the marRAB, soxRS, ramR and acrR operons did not show any mutation and neither did their expression levels in a microarray analysis. A decreased percentage of invasion ability was detected when compared with the susceptible clinical isolate in a gentamicin protection assay. The microarray results revealed a decreased expression of genes which play a role during the invasion process, such as hilA, invF and the flhDC operon. Of note was the impaired growth detected in the resistant strain. A strain with a reverted phenotype (mainly concerning the resistance phenotype) was obtained from the resistant mutant.<h4>Conclusions/significance</h4>In conclusion, a possible link between fluoroquinolone resistance and decreased cell invasion ability may exist explaining the low prevalence of fluoroquinolone-resistant S. Typhimurium clinical isolates. The impaired growth may appear as a consequence of fluoroquinolone resistance acquisition and down-regulate the expression of the invasion genes.Anna FàbregaLaurence du MerleChantal Le BouguénecM Teresa Jiménez de AntaJordi VilaPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 4, Iss 11, p e8029 (2009)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Anna Fàbrega Laurence du Merle Chantal Le Bouguénec M Teresa Jiménez de Anta Jordi Vila Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
description	<h4>Background</h4>Nalidixic acid resistance among Salmonella Typhimurium clinical isolates has steadily increased, whereas the level of ciprofloxacin resistance remains low. The main objective of this study was to characterize the fluoroquinolone resistance mechanisms acquired in a S. Typhimurium mutant selected with ciprofloxacin from a susceptible isolate and to investigate its invasion ability.<h4>Methodology/principal findings</h4>Three different amino acid substitutions were detected in the quinolone target proteins of the resistant mutant (MIC of ciprofloxacin, 64 microg/ml): D87G and G81C in GyrA, and a novel mutation, E470K, in ParE. A protein analysis revealed an increased expression of AcrAB/TolC and decreased expression of OmpC. Sequencing of the marRAB, soxRS, ramR and acrR operons did not show any mutation and neither did their expression levels in a microarray analysis. A decreased percentage of invasion ability was detected when compared with the susceptible clinical isolate in a gentamicin protection assay. The microarray results revealed a decreased expression of genes which play a role during the invasion process, such as hilA, invF and the flhDC operon. Of note was the impaired growth detected in the resistant strain. A strain with a reverted phenotype (mainly concerning the resistance phenotype) was obtained from the resistant mutant.<h4>Conclusions/significance</h4>In conclusion, a possible link between fluoroquinolone resistance and decreased cell invasion ability may exist explaining the low prevalence of fluoroquinolone-resistant S. Typhimurium clinical isolates. The impaired growth may appear as a consequence of fluoroquinolone resistance acquisition and down-regulate the expression of the invasion genes.
format	article
author	Anna Fàbrega Laurence du Merle Chantal Le Bouguénec M Teresa Jiménez de Anta Jordi Vila
author_facet	Anna Fàbrega Laurence du Merle Chantal Le Bouguénec M Teresa Jiménez de Anta Jordi Vila
author_sort	Anna Fàbrega
title	Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
title_short	Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
title_full	Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
title_fullStr	Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
title_full_unstemmed	Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.
title_sort	repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant salmonella typhimurium mutant.
publisher	Public Library of Science (PLoS)
publishDate	2009
url	https://doaj.org/article/f6800048a0f24bee9dcc6967f1516a0e
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Repression of invasion genes and decreased invasion in a high-level fluoroquinolone-resistant Salmonella typhimurium mutant.

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