Intégrons de classe 3 : aspects mécanistiques et épidémiologiques

Abstract : Integrons are bacterial genetic elements able to capture and express genes embedded within gene cassettes. They are widely described among Gram-negative bacteria and generally confer a multidrug resistance phenotype. Resistance integrons (RI) play an important role in the acquisition of antibiotic resistance. There are 3 main classes of RI. Class 3 RI has been poorly studied class with less than ten fully IR3 characterized. Objectives of this thesis were (i) to conduct an epidemiological study of class 3 RI in France and Cameroon and (ii) to better understand the modes of expression of the integrase and cassettes of IR3. We described 3 new class 3 RI isolated from environmental bacteria belonging to genus Aeromonas, Acinetobacter and Citrobacter. Gene cassettes encoded resistance to betalactams, aminoglycosides and quaternary ammonium compounds. We also described IR3 from three Delftia strains (2 D.acidovorans and 1 D.tsuruhatensis) in Africa containing cassettes that do not encode antibiotic resistance. The fundamental part of the work showed that the PintI3(1) promoter is involved in the expression of the intI3 gene. Furthermore, we demonstrated that variants of the Pc promoter and variants of the PintI3(1) promoter are functional with different strengths. These results showed that the environment may constitute a reservoir of class 3 integrons and that these genetic elements could play an important role in the spread of the resistance in this ecosystem.
Document type :
Theses
Complete list of metadatas

Cited literature [151 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01314131
Contributor : Abes Star <>
Submitted on : Tuesday, May 10, 2016 - 6:56:31 PM
Last modification on : Thursday, July 5, 2018 - 3:25:06 PM
Long-term archiving on : Wednesday, May 25, 2016 - 8:57:59 AM

File

2016LIMO0009.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01314131, version 1

Collections

Citation

Pierrette Landrie Simo Tchuinte. Intégrons de classe 3 : aspects mécanistiques et épidémiologiques. Médecine humaine et pathologie. Université de Limoges, 2016. Français. ⟨NNT : 2016LIMO0009⟩. ⟨tel-01314131⟩

Share

Metrics

Record views

427

Files downloads

1593