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Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates

Enterococcus faecalis is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24–70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observe...

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Autores principales: Bernardi, Sara, Anderson, Annette, Macchiarelli, Guido, Hellwig, Elmar, Cieplik, Fabian, Vach, Kirstin, Al-Ahmad, Ali
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8300655/
https://www.ncbi.nlm.nih.gov/pubmed/34356795
http://dx.doi.org/10.3390/antibiotics10070874
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author Bernardi, Sara
Anderson, Annette
Macchiarelli, Guido
Hellwig, Elmar
Cieplik, Fabian
Vach, Kirstin
Al-Ahmad, Ali
author_facet Bernardi, Sara
Anderson, Annette
Macchiarelli, Guido
Hellwig, Elmar
Cieplik, Fabian
Vach, Kirstin
Al-Ahmad, Ali
author_sort Bernardi, Sara
collection PubMed
description Enterococcus faecalis is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24–70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observed for a wide variety of bacterial pathogens and is associated with increased resistance. In this study, therefore, six E. faecalis isolates from an endodontic environment and two control strains were exposed to subinhibitory concentrations of Penicillin G, Amoxicillin, Doxycycline, Fosfomycin, Tetracycline and Vancomycin and examined for their biofilm formation abilities. The minimum inhibitory concentration (MIC) was determined for all E. faecalis isolates. A culture of the isolate was mixed with a serial dilution series of the respective antibiotic, incubated overnight and the biofilm formation was analyzed using a microtiter plate assay. All isolates were able to form biofilms in the absence of an antibiotic. A significant increase in biofilm formation of up to more than 50% was found in the isolates exposed to subinhibitory concentrations of various antibiotics. Most isolates showed a significant increase in Fosfomycin (7/8), Doxycycline (6/8) and Tetracycline (6/8). Three endodontic isolates showed a significant increase in five of the antibiotics examined at the same time. On exposure to Vancomycin, three endodontic isolates and the two control strains showed an increase. The increase in the ability to form biofilms extended over a concentration range from 1/2 to 1/64 of the MIC concentration. Antibiotics may reach certain niches in the oral cavity at subinhibitory concentrations only. This can increase the biofilm formation by enterococci, and in turn lead to decreased susceptibility of these taxa to antibiotics.
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spelling pubmed-83006552021-07-24 Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates Bernardi, Sara Anderson, Annette Macchiarelli, Guido Hellwig, Elmar Cieplik, Fabian Vach, Kirstin Al-Ahmad, Ali Antibiotics (Basel) Article Enterococcus faecalis is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24–70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observed for a wide variety of bacterial pathogens and is associated with increased resistance. In this study, therefore, six E. faecalis isolates from an endodontic environment and two control strains were exposed to subinhibitory concentrations of Penicillin G, Amoxicillin, Doxycycline, Fosfomycin, Tetracycline and Vancomycin and examined for their biofilm formation abilities. The minimum inhibitory concentration (MIC) was determined for all E. faecalis isolates. A culture of the isolate was mixed with a serial dilution series of the respective antibiotic, incubated overnight and the biofilm formation was analyzed using a microtiter plate assay. All isolates were able to form biofilms in the absence of an antibiotic. A significant increase in biofilm formation of up to more than 50% was found in the isolates exposed to subinhibitory concentrations of various antibiotics. Most isolates showed a significant increase in Fosfomycin (7/8), Doxycycline (6/8) and Tetracycline (6/8). Three endodontic isolates showed a significant increase in five of the antibiotics examined at the same time. On exposure to Vancomycin, three endodontic isolates and the two control strains showed an increase. The increase in the ability to form biofilms extended over a concentration range from 1/2 to 1/64 of the MIC concentration. Antibiotics may reach certain niches in the oral cavity at subinhibitory concentrations only. This can increase the biofilm formation by enterococci, and in turn lead to decreased susceptibility of these taxa to antibiotics. MDPI 2021-07-19 /pmc/articles/PMC8300655/ /pubmed/34356795 http://dx.doi.org/10.3390/antibiotics10070874 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Bernardi, Sara
Anderson, Annette
Macchiarelli, Guido
Hellwig, Elmar
Cieplik, Fabian
Vach, Kirstin
Al-Ahmad, Ali
Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title_full Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title_fullStr Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title_full_unstemmed Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title_short Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates
title_sort subinhibitory antibiotic concentrations enhance biofilm formation of clinical enterococcus faecalis isolates
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8300655/
https://www.ncbi.nlm.nih.gov/pubmed/34356795
http://dx.doi.org/10.3390/antibiotics10070874
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