Please use this identifier to cite or link to this item:
https://hdl.handle.net/10216/123473
Author(s): | Merilin Rosenberg Nuno F. Azevedo Angela Ivask |
Title: | Propidium iodide staining underestimates viability of adherent bacterial cells |
Issue Date: | 2019 |
Abstract: | Combining membrane impermeable DNA-binding stain propidium iodide (PI) with membrane-permeable DNA-binding counterstains is a widely used approach for bacterial viability staining. In this paper we show that PI staining of adherent cells in biofilms may significantly underestimate bacterial viability due to the presence of extracellular nucleic acids (eNA). We demonstrate that gram-positive Staphylococcus epidermidis and gram-negative Escherichia coli 24-hour initial biofilms on glass consist of 76 and 96% PI-positive red cells in situ, respectively, even though 68% the cells of either species in these aggregates are metabolically active. Furthermore, 82% of E. coli and 89% S. epidermidis are cultivable after harvesting. Confocal laser scanning microscopy (CLSM) revealed that this false dead layer of red cells is due to a subpopulation of double-stained cells that have green interiors under red coating layer which hints at eNA being stained outside intact membranes. Therefore, viability staining results of adherent cells should always be validated by an alternative method for estimating viability, preferably by cultivation. |
URI: | https://hdl.handle.net/10216/123473 |
Related Information: | info:eu-repo/grantAgreement/Comissão de Coordenação e Desenvolvimento Regional do Norte/P2020|Norte2020-Projetos Integrados ICDT/NORTE-01-0145-FEDER-000005/LEPABE-2-ECO-INNOVATION/LEPABE-2-ECO-INNOVATION info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Programa de Financiamento Plurianual de Unidades de I&D/UID/EQU/00511/2019 /Projeto Estratégico do LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia/LEPABE |
Document Type: | Artigo em Revista Científica Internacional |
Rights: | openAccess |
Appears in Collections: | FEUP - Artigo em Revista Científica Internacional |
Files in This Item:
File | Description | Size | Format | |
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363114.pdf | 1.9 MB | Adobe PDF | View/Open |
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