Your browser doesn't support javascript.
loading
Unravelling of a mechanism of resistance to colistin in Klebsiella pneumoniae using atomic force microscopy.
Formosa, C; Herold, M; Vidaillac, C; Duval, R E; Dague, E.
Afiliación
  • Formosa C; CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse, France Université de Toulouse, LAAS, F-31400 Toulouse, France CNRS, UMR 7565, SRSMC, F-54506 Vandœuvre-lès-Nancy, France Université de Lorraine, UMR 7565, SRSMC, Faculté de Pharmacie, F-54001 Nancy, France.
  • Herold M; CNRS, UMR 7565, SRSMC, F-54506 Vandœuvre-lès-Nancy, France Université de Lorraine, UMR 7565, SRSMC, Faculté de Pharmacie, F-54001 Nancy, France ABC Platform, F-54001 Nancy, France.
  • Vidaillac C; CNRS, UMR 7565, SRSMC, F-54506 Vandœuvre-lès-Nancy, France Université de Lorraine, UMR 7565, SRSMC, Faculté de Pharmacie, F-54001 Nancy, France.
  • Duval RE; CNRS, UMR 7565, SRSMC, F-54506 Vandœuvre-lès-Nancy, France Université de Lorraine, UMR 7565, SRSMC, Faculté de Pharmacie, F-54001 Nancy, France ABC Platform, F-54001 Nancy, France.
  • Dague E; CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse, France Université de Toulouse, LAAS, F-31400 Toulouse, France edague@laas.fr.
J Antimicrob Chemother ; 70(8): 2261-70, 2015 Aug.
Article en En | MEDLINE | ID: mdl-26017037
OBJECTIVES: In this study we focused on the mechanism of colistin resistance in Klebsiella pneumoniae. METHODS: We used two strains of K. pneumoniae: a colistin-susceptible strain (K. pneumoniae ATCC 700603, KpATCC) and its colistin-resistant derivative (KpATCCm, MIC of colistin 16 mg/L). We performed a genotypic analysis based on the expression of genes involved in LPS synthesis and L-Ara4N moiety addition. We also explored the status of the mgrB gene. Then, a phenotypic analysis was performed using atomic force microscopy (AFM). The Young modulus was extracted from force curves fitted using the Hertz model, and stiffness values were extracted from force curves fitted using the Hooke model. RESULTS: We failed to observe any variation in the expression of genes implicated in LPS synthesis or L-Ara4N moiety addition in KpATCCm, in the absence of colistin or under colistin pressure (versus KpATCC). This led us to identify an insertional inactivation/mutation in the mgrB gene of KpATCCm. In addition, morphology results obtained by AFM showed that colistin removed the capsule from the susceptible strain, but not from the resistant strain. Nanomechanical data on the resistant strain showed that colistin increased the Young modulus of the capsule. Extend force curves recorded on top of the cells allowed us to make the following hypothesis about the nanoarchitecture of the capsule of the two strains: KpATCC has a soft capsule consisting of one layer, whereas the KpATCCm capsule is harder and organized in several layers. CONCLUSIONS: We hypothesize that capsular polysaccharides might be implicated in the mechanism of colistin resistance in K. pneumoniae, depending on its genotype.
Asunto(s)
Palabras clave
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Colistina / Microscopía de Fuerza Atómica / Farmacorresistencia Bacteriana / Klebsiella pneumoniae / Antibacterianos Idioma: En Revista: J Antimicrob Chemother Año: 2015 Tipo del documento: Article País de afiliación: Francia Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Colistina / Microscopía de Fuerza Atómica / Farmacorresistencia Bacteriana / Klebsiella pneumoniae / Antibacterianos Idioma: En Revista: J Antimicrob Chemother Año: 2015 Tipo del documento: Article País de afiliación: Francia Pais de publicación: Reino Unido