Author(s):
Silva, A. ; Sousa, Ana Margarida ; Alves, Diana ; Lourenço, Anália ; Pereira, Maria Olívia
Date: 2016
Persistent ID: http://hdl.handle.net/1822/44723
Origin: RepositóriUM - Universidade do Minho
Project/scholarship:
info:eu-repo/grantAgreement/FCT/5876/147337/PT;
info:eu-repo/grantAgreement/FCT/5876-PPCDTI/113196/PT
;
info:eu-repo/grantAgreement/FCT/5876-PPCDTI/126270/PT
;
info:eu-repo/grantAgreement/FCT/COMPETE/126270/PT;
info:eu-repo/grantAgreement/EC/FP7/316265/EU;
info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F72551%2F2010/PT;
Subject(s): Klebsiella pneumoniae; Colistin; Heteroresistance; Biofilms; Small colony variants; biofilm; Science & Technology
Description
The emergence of Klebsiella pneumoniae multidrug-resistant strains pave the way to the re-introduction of colistin as a salvage therapy. However, recent planktonic studies have reported several cases of heteroresistance to this antimicrobial agent. The aim of the present work was to gain better understanding about the response of K. pneumoniae biofilms to colistin antibiotherapy and inspect the occurrence of heteroresistance in biofilm-derived cells. Biofilm formation and its susceptibility to colistin was evaluated through the determination of biofilm-cells viability. The profiling of planktonic and biofilm cell populations was conducted to assess the occurrence of heteroresistance. Colony morphology was further characterised in order to inspect the potential role of colistin in K. pneumoniae phenotypic differentiation. Results show that K. pneumoniae was susceptible to colistin in its planktonic form, but biofilms presented enhanced resistance. Population analysis profiles pointed out that K. pneumoniae manifest heteroresistance to colistin only when grown in biofilm arrangements, and it was possible to identify a resistant sub-population presenting a small colony morphology (diameter around 5 mm). To the best of our knowledge, this is the first report linking heteroresistance to biofilm formation and a morphological distinctive sub-population. Moreover, this is the first evidence that biofilm formation can trigger the emergence of heteroresistance in an apparently susceptible strain.
This work was supported by the Portuguese Foundation for Science and Technology (FCT), under the strategic funding of UID/BIO/04469/2013 unit, by FCT and the European Community fund FEDER, through Program COMPETE, under the scope of the projects AntiPep PTDC/SAU-SAP/113196/2009 (FCOMP-01-0124-FEDER-016012), RECI/BBBEBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and by the Agrupamento INBIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273) and the European Union's Seventh Framework Programme FP7/REGPOT-2012-2013.1 (grant number 316265), BIOCAPS. The authors also thank FCT for the PhD Grants of Diana Alves (SFRH/BD/78063/2011) and Ana Margarida Sousa (SFRH/BD/72551/2010). This document reflects only the author’s views and the European Union is not liable for any use that may be made of the information contained herein.PTDC/SAU-SAP/113196/2009 (FCOMP-01-0124-FEDER-016012), RECI/BBBEBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and by the Agrupamento INBIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273) and the European Union's Seventh Framework Programme FP7/REGPOT-2012-2013.1 (grant number 316265), BIOCAPS. The authors also thank FCT for the PhD Grants of Diana Alves (SFRH/BD/78063/2011) and Ana Margarida Sousa (SFRH/BD/72551/2010). This document reflects only the author’s views and the European Union is not liable for any use that may be made of the information contained herein.
