Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface

<i>Staphylococcus aureus</i> are frequently associated with biofilm formation on intravascular devices. Biofilms limit antimicrobial penetration and promote phenotypic resistance, challenging conventional treatment strategies. Vancomycin (VAN) and gentamicin (GEN) have been used clinical...

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Main Authors: Nicolas Henrique Borges, Paula Hansen Suss, Gabriel Burato Ortis, Leticia Ramos Dantas, Felipe Francisco Tuon
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/5/1119
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author Nicolas Henrique Borges
Paula Hansen Suss
Gabriel Burato Ortis
Leticia Ramos Dantas
Felipe Francisco Tuon
author_facet Nicolas Henrique Borges
Paula Hansen Suss
Gabriel Burato Ortis
Leticia Ramos Dantas
Felipe Francisco Tuon
author_sort Nicolas Henrique Borges
collection DOAJ
description <i>Staphylococcus aureus</i> are frequently associated with biofilm formation on intravascular devices. Biofilms limit antimicrobial penetration and promote phenotypic resistance, challenging conventional treatment strategies. Vancomycin (VAN) and gentamicin (GEN) have been used clinically, but their combined antibiofilm activity remains underexplored. This study evaluates the efficacy of VAN and GEN, alone and in combination, against biofilms formed by methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) and methicillin-sensitive <i>S. aureus</i> (MSSA) on polyurethane. MICs were determined for VAN and GEN. Biofilm biomass and metabolic activity were quantified using crystal violet and MTT assays, respectively. Biofilm viability was assessed through fluorescence microscopy and a modified Calgary Biofilm Device. A continuous-flow peristaltic model was developed to test treatment under simulated catheter conditions. While monotherapy with VAN or GEN had modest effects, their combination significantly reduced biomass and metabolic activity. VAN 20 mg/L + GEN 8 mg/L and VAN 40 mg/L + GEN 8 mg/L achieved over 70% reduction in MRSA biofilm viability and complete eradication in MBEC assays. Dynamic model assays confirmed biofilm reduction with combination therapy. The combination of VAN/GEN exhibits synergistic antibiofilm activity against <i>S. aureus</i>, particularly MRSA. These findings support its potential application in catheter salvage strategies, including antibiotic lock therapy.
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spelling doaj-art-8508cc12ea544167bc7da4b1d3a06ecd2025-08-20T03:14:35ZengMDPI AGMicroorganisms2076-26072025-05-01135111910.3390/microorganisms13051119Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane SurfaceNicolas Henrique Borges0Paula Hansen Suss1Gabriel Burato Ortis2Leticia Ramos Dantas3Felipe Francisco Tuon4Laboratory of Emerging Infectious Diseases, School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, BrazilLaboratory of Emerging Infectious Diseases, School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, BrazilLaboratory of Emerging Infectious Diseases, School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, BrazilLaboratory of Emerging Infectious Diseases, School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, BrazilLaboratory of Emerging Infectious Diseases, School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil<i>Staphylococcus aureus</i> are frequently associated with biofilm formation on intravascular devices. Biofilms limit antimicrobial penetration and promote phenotypic resistance, challenging conventional treatment strategies. Vancomycin (VAN) and gentamicin (GEN) have been used clinically, but their combined antibiofilm activity remains underexplored. This study evaluates the efficacy of VAN and GEN, alone and in combination, against biofilms formed by methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) and methicillin-sensitive <i>S. aureus</i> (MSSA) on polyurethane. MICs were determined for VAN and GEN. Biofilm biomass and metabolic activity were quantified using crystal violet and MTT assays, respectively. Biofilm viability was assessed through fluorescence microscopy and a modified Calgary Biofilm Device. A continuous-flow peristaltic model was developed to test treatment under simulated catheter conditions. While monotherapy with VAN or GEN had modest effects, their combination significantly reduced biomass and metabolic activity. VAN 20 mg/L + GEN 8 mg/L and VAN 40 mg/L + GEN 8 mg/L achieved over 70% reduction in MRSA biofilm viability and complete eradication in MBEC assays. Dynamic model assays confirmed biofilm reduction with combination therapy. The combination of VAN/GEN exhibits synergistic antibiofilm activity against <i>S. aureus</i>, particularly MRSA. These findings support its potential application in catheter salvage strategies, including antibiotic lock therapy.https://www.mdpi.com/2076-2607/13/5/1119vancomycingentamicinbiofilm<i>Staphylococcus aureus</i>catheterlock therapy
spellingShingle Nicolas Henrique Borges
Paula Hansen Suss
Gabriel Burato Ortis
Leticia Ramos Dantas
Felipe Francisco Tuon
Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
Microorganisms
vancomycin
gentamicin
biofilm
<i>Staphylococcus aureus</i>
catheter
lock therapy
title Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
title_full Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
title_fullStr Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
title_full_unstemmed Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
title_short Synergistic Activity of Vancomycin and Gentamicin Against <i>Staphylococcus aureus</i> Biofilms on Polyurethane Surface
title_sort synergistic activity of vancomycin and gentamicin against i staphylococcus aureus i biofilms on polyurethane surface
topic vancomycin
gentamicin
biofilm
<i>Staphylococcus aureus</i>
catheter
lock therapy
url https://www.mdpi.com/2076-2607/13/5/1119
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AT gabrielburatoortis synergisticactivityofvancomycinandgentamicinagainstistaphylococcusaureusibiofilmsonpolyurethanesurface
AT leticiaramosdantas synergisticactivityofvancomycinandgentamicinagainstistaphylococcusaureusibiofilmsonpolyurethanesurface
AT felipefranciscotuon synergisticactivityofvancomycinandgentamicinagainstistaphylococcusaureusibiofilmsonpolyurethanesurface