Publications by authors named "Sophie Guillier"

5 Publications

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Genomic and RT-qPCR analysis of trimethoprim-sulfamethoxazole and meropenem resistance in Burkholderia pseudomallei clinical isolates.

PLoS Negl Trop Dis 2021 02 16;15(2):e0008913. Epub 2021 Feb 16.

Bacteriology Unit, UMR-MD1 INSERM 1261, French Armed Biomedical Research Institut, Brétigny-sur-Orge, France.

Background: Melioidosis is an endemic disease in southeast Asia and northern Australia caused by the saprophytic bacteria Burkholderia pseudomallei, with a high mortality rate. The clinical presentation is multifaceted, with symptoms ranging from acute septicemia to multiple chronic abscesses. Here, we report a chronic case of melioidosis in a patient who lived in Malaysia in the 70s and was suspected of contracting tuberculosis. Approximately 40 years later, in 2014, he was diagnosed with pauci-symptomatic melioidosis during a routine examination. Four strains were isolated from a single sample. They showed divergent morphotypes and divergent antibiotic susceptibility, with some strains showing resistance to trimethoprim-sulfamethoxazole and fluoroquinolones. In 2016, clinical samples were still positive for B. pseudomallei, and only one type of strain, showing atypical resistance to meropenem, was isolated.

Principal Findings: We performed whole genome sequencing and RT-qPCR analysis on the strains isolated during this study to gain further insights into their differences. We thus identified two types of resistance mechanisms in these clinical strains. The first one was an adaptive and transient mechanism that disappeared during the course of laboratory sub-cultures; the second was a mutation in the efflux pump regulator amrR, associated with the overexpression of the related transporter.

Conclusion: The development of such mechanisms may have a clinical impact on antibiotic treatment. Indeed, their transient nature could lead to an undiagnosed resistance. Efflux overexpression due to mutation leads to an important multiple resistance, reducing the effectiveness of antibiotics during treatment.
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http://dx.doi.org/10.1371/journal.pntd.0008913DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7909661PMC
February 2021

Natural outbreaks and bioterrorism: How to deal with the two sides of the same coin?

J Glob Health 2020 Dec;10(2):020317

Bacteriology Unit, French Armed Forces Biomedical Research Institute (IRBA), Bretigny sur Orge, France.

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http://dx.doi.org/10.7189/jogh.10.020317DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7535343PMC
December 2020

Transcriptomic studies and assessment of Yersinia pestis reference genes in various conditions.

Sci Rep 2019 02 21;9(1):2501. Epub 2019 Feb 21.

Institut de Recherche Biomédicale des Armées (IRBA), Brétigny-sur-Orge, France.

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is a very sensitive widespread technique considered as the gold standard to explore transcriptional variations. While a particular methodology has to be followed to provide accurate results many published studies are likely to misinterpret results due to lack of minimal quality requirements. Yersinia pestis is a highly pathogenic bacterium responsible for plague. It has been used to propose a ready-to-use and complete approach to mitigate the risk of technical biases in transcriptomic studies. The selection of suitable reference genes (RGs) among 29 candidates was performed using four different methods (GeNorm, NormFinder, BestKeeper and the Delta-Ct method). An overall comprehensive ranking revealed that 12 following candidate RGs are suitable for accurate normalization: gmk, proC, fabD, rpoD, nadB, rho, thrA, ribD, mutL, rpoB, adk and tmk. Some frequently used genes like 16S RNA had even been found as unsuitable to study Y. pestis. This methodology allowed us to demonstrate, under different temperatures and states of growth, significant transcriptional changes of six efflux pumps genes involved in physiological aspects as antimicrobial resistance or virulence. Previous transcriptomic studies done under comparable conditions had not been able to highlight these transcriptional modifications. These results highlight the importance of validating RGs prior to the normalization of transcriptional expression levels of targeted genes. This accurate methodology can be extended to any gene of interest in Y. pestis. More generally, the same workflow can be applied to identify and validate appropriate RGs in other bacteria to study transcriptional variations.
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http://dx.doi.org/10.1038/s41598-019-39072-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6385181PMC
February 2019

Engineering of large numbers of highly specific homing endonucleases that induce recombination on novel DNA targets.

J Mol Biol 2006 Jan 15;355(3):443-58. Epub 2005 Nov 15.

CELLECTIS S.A., 102 route de Noisy 93235 Romainville, France.

The last decade has seen the emergence of a universal method for precise and efficient genome engineering. This method relies on the use of sequence-specific endonucleases such as homing endonucleases. The structures of several of these proteins are known, allowing for site-directed mutagenesis of residues essential for DNA binding. Here, we show that a semi-rational approach can be used to derive hundreds of novel proteins from I-CreI, a homing endonuclease from the LAGLIDADG family. These novel endonucleases display a wide range of cleavage patterns in yeast and mammalian cells that in most cases are highly specific and distinct from I-CreI. Second, rules for protein/DNA interaction can be inferred from statistical analysis. Third, novel endonucleases can be combined to create heterodimeric protein species, thereby greatly enhancing the number of potential targets. These results describe a straightforward approach for engineering novel endonucleases with tailored specificities, while preserving the activity and specificity of natural homing endonucleases, and thereby deliver new tools for genome engineering.
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http://dx.doi.org/10.1016/j.jmb.2005.10.065DOI Listing
January 2006

In vivo selection of engineered homing endonucleases using double-strand break induced homologous recombination.

Nucleic Acids Res 2005 Nov 23;33(20):e178. Epub 2005 Nov 23.

CELLECTIS S.A., 102 route de Noisy 93235, Romainville, France.

Homing endonucleases, endonucleases capable of recognizing long DNA sequences, have been shown to be a tool of choice for precise and efficient genome engineering. Consequently, the possibility to engineer novel endonucleases with tailored specificities is under strong investigation. In this report, we present a simple and efficient method to select meganucleases from libraries of variants, based on their cleavage properties. The method has the advantage of directly selecting for the ability to induce double-strand break induced homologous recombination in a eukaryotic environment. Model selections demonstrated high levels of enrichments. Moreover, this method compared favorably with phage display for enrichment of active mutants from a mutant library. This approach makes possible the exploration of large sequence spaces and thereby represents a valuable tool for genome engineering.
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http://dx.doi.org/10.1093/nar/gni175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1289081PMC
November 2005