scholarly journals Established Gardnerella biofilms can survive metronidazole treatment by reducing metabolic activity

2021 ◽  
Author(s):  
Salahuddin Khan ◽  
Janet E Hill
Keyword(s):  
Bacterial Vaginosis ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
Inhibitory Concentration ◽  
Growth Media ◽  
Growth Modes ◽  
Resazurin Assay ◽  
Bactericidal Effects ◽  
Planktonic Form ◽  
Highly Correlated

Gardnerella spp., a hallmark of bacterial vaginosis, can form biofilm and it has been suggested that failure of antibiotic treatment of bacterial vaginosis and recurrent vaginosis are linked to its ability to form biofilm. Here, we tested the hypothesis that biofilm formation provides protection from the effects of metronidazole. We performed a broth microdilution assay to measure the minimum inhibitory concentration (MIC) of metronidazole for thirty-five Gardnerella isolates in two different growth media: one medium in which Gardnerella spp. grow primarily as biofilm and the other medium in which Gardnerella spp. grow primarily in planktonic form. The MIC of Gardnerella isolates observed in the two conditions were highly correlated (R2= 0.69, p <0.001) and 27/35 isolates had no difference in MIC between the two growth modes. When established biofilms were treated with metronidazole, live Gardnerella could be recovered following treatment in most cases (7/9 isolates tested). Metabolic activity of established biofilms of thirty-one isolates with and without metronidazole treatment was measured using a resazurin assay. Most (27/31) isolates showed reduced metabolic activity following treatment with μ128 g/ml of metronidazole relative to untreated controls. The amount of biofilm produced by Gardnerella isolates was not enhanced by sub-inhibitory concentrations of metronidazole and scanning electron microscopy revealed no architectural differences between treated and untreated biofilms. Our results suggest that Gardnerella spp. growing in established biofilms reduce metabolic activity as a mechanism of protection from the bactericidal effects of metronidazole.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

scholarly journals Action ofCoriandrum sativumL. Essential Oil upon OralCandida albicansBiofilm Formation

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
V. F. Furletti ◽  
I. P. Teixeira ◽  
G. Obando-Pereda ◽  
R. C. Mardegan ◽  
A. Sartoratto ◽  
...  
Keyword(s):  
Essential Oil ◽  
Biofilm Formation ◽  
Plant Material ◽  
Inhibitory Concentration ◽  
Chemical Characterization ◽  
Synergistic Action ◽  
Biofilm Growth ◽  
Water Distillation ◽  
Microdilution Method

The efficacy of extracts and essential oils fromAllium tuberosum, Coriandrum sativum, Cymbopogon martini, Cymbopogon winterianus,andSantolina chamaecyparissuswas evaluated againstCandidaspp. isolates from the oral cavity of patients with periodontal disease. The most active oil was fractionated and tested againstC. albicansbiofilm formation. The oils were obtained by water-distillation and the extracts were prepared with macerated dried plant material. The Minimal Inhibitory Concentration—MIC was determined by the microdilution method. Chemical characterization of oil constituents was performed using Gas Chromatography and Mass Spectrometry (GC-MS). C. sativum activity oil upon cell and biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). The best activities against planktonicCandidaspp. were observed for the essential oil and the grouped F8–10fractions fromC. sativum. The crude oil also affected the biofilm formation inC. albicanscausing a decrease in the biofilm growth. Chemical analysis of the F8–10fractions detected as major active compounds, 2-hexen-1-ol, 3-hexen-1-ol and cyclodecane. Standards of these compounds tested grouped provided a stronger activity than the oil suggesting a synergistic action from the major oil constituents. The activity ofC. sativumoil demonstrates its potential for a new natural antifungal formulation.

scholarly journals Starvation Survival and Biofilm Formation under Subminimum Inhibitory Concentration of QAMs

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sanjay Kumar Tiwari ◽  
Suping Wang ◽  
Yannan Huang ◽  
Xuedong Zhou ◽  
Hockin H. K. Xu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Biofilm Formation ◽  
Acid Production ◽  
Inhibitory Concentration ◽  
Lactic Acid Production ◽  
Oral Bacteria ◽  
Laser Scanning Microscopy ◽  
Prolonged Starvation ◽  
Survival And Development ◽  
Development Of Tolerance

Quaternary ammonium methacrylates (QAMs) are useful antimicrobial compounds against oral bacteria. Here, we investigated the effects of two QAMs, dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM), on biofilm formation, survival and development of tolerance by biofilm, and survival and development of tolerance against QAMs after prolonged starvation. Enterococcus faecalis (E. faecalis), Streptococcus gordonii (S. gordonii), Lactobacillus acidophilus (L. acidophilus), and Actinomyces naeslundii (A. naeslundii) were used. Minimum inhibitory concentration (MIC) of QAMs against multispecies biofilm was determined. Biofilm formed under sub-MIC was observed by crystal violet staining and confocal laser scanning microscopy (CLSM). Metabolic activity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid production measurement. Development of tolerance was determined by MIC values before and after exposure to QAMs or after prolonged starvation. It was found that E. faecalis and S. gordonii could survive and form biofilm under sub-MIC of QAMs. Lactic acid production from biofilms formed under sub-MIC was significantly higher than control specimens ( p < 0.05 ). The exposure to sub-MIC of QAMs promoted biofilm formation, and prolonged starvation or prolonged contact with sub-MIC helped bacteria develop tolerance against killing by QAMs.

scholarly journals Antimicrobial and antibiofilm properties of essential oils from Piper marginatum Jacq.

2021 ◽  
Vol 10 (11) ◽  
pp. e514101119967
Author(s):  
Ana Lúcia Mendes dos Santos ◽  
Filipe Augusto Matos Araújo ◽  
Érika da Silva Matisui ◽  
Luiz Antonio Mendonça Alves da Costa ◽  
Alexandre José Macêdo ◽  
...  
Keyword(s):  
Essential Oils ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Folk Medicine ◽  
Gram Negative Bacteria ◽  
Biofilm Inhibition ◽  
Future Developments ◽  
Phytochemical Constituents ◽  
Amazonian Region

A low shrub growing in the Amazonian region, Piper marginatum Jacq. has been related to the treatment of a disease variety in folk medicine, however, still lacking scientific support. This study aimed to describe the composition of essential oils obtained from leaves (EOL) and branches (EOB) of P. marginatum and their antimicrobial effects on six relevant pathogenic bacteria. A combination of GC-FID and GC-MS was used to identify the phytochemical constituents. As antimicrobial assays, the oils were screened at the minimum inhibitory concentration (MIC) of 3 µg/ml for planktonic and biofilm inhibition. EOL revealed the presence of trans–nerolidol, o–cymene, spathulenol, elemicin, and α–copaene, while EOB composition was mainly of myristicin, trans-caryophyllene, trans-nerolidol, caryophyllene oxide, α–copaene, γ–muurolene and spathulenol. The strongest inhibition of planktonic growth was achieved against Pseudomonas aeruginosa (EOB) and Escherichia coli (EOB). Overall, Gram negative bacteria were more sensitive to both EOB/EOL showing less ability of growth and biofilm formation. The Gram-positive strains seemed to react to the essential oils by massive adhesion. Our results corroborate the relevance of Piperaceae and indicate the possible use of P. marginatum in future developments of antimicrobials.

scholarly journals Darunavir inhibits Cryptococcus neoformans/Cryptococcus gattii species complex growth and increases the susceptibility of biofilms to antifungal drugs

2020 ◽  
Vol 69 (6) ◽  
pp. 830-837
Author(s):  
Raimunda Sâmia Nogueira Brilhante ◽  
José Alexandre Telmos Silva ◽  
Géssica dos Santos Araújo ◽  
Vandbergue Santos Pereira ◽  
Wilker Jose Perez Gotay ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
Species Complex ◽  
Cryptococcus Gattii ◽  
Antifungal Drugs ◽  
Planktonic Cells ◽  
Species Activity ◽  
Checkerboard Assay

Introduction. Cryptococcus species are pathogens commonly associated with cases of meningoencephalitis in individuals who are immunosuppressed due to AIDS. Aim. The aim was to evaluate the effects of the antiretroviral darunavir alone or associated with fluconazole, 5-flucytosine and amphotericin B against planktonic cells and biofilms of Cryptococcus species. Methodology. Susceptibility testing of darunavir and the common antifungals against 12 members of the Cryptococcus neoformans/Cryptococcus gattii species complex was evaluated by broth microdilution. The interaction between darunavir and antifungals against planktonic cells was tested by a checkerboard assay. The effects of darunavir against biofilm metabolic activity and biomass were evaluated by the XTT reduction assay and crystal violet staining, respectively. Results. Darunavir combined with amphotericin B showed a synergistic interaction against planktonic cells. No antagonistic interaction was observed between darunavir and the antifungals used. All Cryptococcus species strains were strong biofilm producers. Darunavir alone reduced biofilm metabolic activity and biomass when added during and after biofilm formation (P<0.05). The combination of darunavir with antifungals caused a significant reduction in biofilm metabolic activity and biomass when compared to darunavir alone (P<0.05). Conclusion. Darunavir presents antifungal activity against planktonic cells of Cryptococcus species and synergism with amphotericin B. In addition, darunavir led to reduced biofilm formation and showed activity against mature biofilms of Cryptococcus species. Activity of the antifungals against mature biofilms was enhanced in the presence of darunavir.

Evidence that the mechanisms of fungitoxicity of 8-quinolinol and its bischelate with copper(II) are different

1985 ◽  
Vol 31 (8) ◽  
pp. 707-710 ◽  
Author(s):  
Herman Gershon ◽  
Anthony T. Grefig ◽  
David J. Cady
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Graphite Furnace ◽  
Trichoderma Viride ◽  
Atomic Absorption Spectrophotometry ◽  
Test System ◽  
Growth Media ◽  
Minimal Inhibitory Concentrations ◽  
Absorption Spectrophotometry ◽  
Inhibition Of Growth

The copper(II) contents of the growth media, Sabouraud dextrose and Czapek–Dox broths, and of the spore inocula of Aspergillus niger (ATCC 1004), Aspergillus oryzae (ATCC 1011), Trichoderma viride (ATCC 8678), and Myrothecium verrucaria (ATCC 9095) were determined by atomic absorption spectrophotometry in a graphite furnace. The test systems composed of Sabouraud dextrose broth and spore inocula of the four fungi contained only a little over 3% of the copper(II) required to form a minimal inhibitory concentration of bis(8-quinolinolato)copper(II). The test system of Czapek–Dox broth and A. oryzae contained slightly less than 65% of the copper(II) required to form a minimal inhibitory concentration of the bischelate of 8-quinolinol with copper(II). When the minimal inhibitory concentrations of 8-quinolinol and bis(8-quinolinolato)copper(II) were added simultaneously to the test system of Czapek–Dox broth and A. oryzae, 10% of the combined mixture of toxicants caused complete inhibition of growth indicating synergism between the toxicants. These results together with the observation that α-lipoic acid as well as small aliphatic thiol-containing compounds (cysteine, glutathione, dithioerythritol, and dithiothreitol) reversed the toxicity of 8-quinolinol but not the toxicity of bis(8-quinolinolato)copper(II) led to the conclusion that the mechanisms of fungitoxicity of both toxicants are different.

scholarly journals Evaluation of Alternative Methods to Assess the Biological Properties of Propolis on Metabolic Activity and Biofilm Formation in Streptococcus mutans

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jorge Jesús Veloz ◽  
Marysol Alvear ◽  
Luis A. Salazar
Keyword(s):  
Flow Cytometry ◽  
Confocal Microscopy ◽  
Streptococcus Mutans ◽  
Metabolic Activity ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Biological Activities ◽  
Biological Properties ◽  
Alternative Methods ◽  
Flow Cytometry Analysis

Several biological activities have been reported for the Chilean propolis, among their antimicrobial and antibiofilm properties, due to its high polyphenol content. In this study, we evaluate alternative methods to assess the effect of Chilean propolis on biofilm formation and metabolic activity of Streptococcus mutans (S. mutans), a major cariogenic agent in oral cavity. Biofilm formation was studied by using crystal violet and by confocal microscopy. The metabolic activity of biofilm was evaluated by MTT and by flow cytometry analysis. The results show that propolis reduces biofilm formation and biofilm metabolic activity in S. mutans. When the variability of the methods to measure biofilm formation was compared, the coefficient of variation (CV) fluctuated between 12.8 and 23.1% when using crystal violet methodology. On the other hand, the CV ranged between 2.2 and 3.3% with confocal microscopy analysis. The CV for biofilm’s metabolic activity measured by MTT methodology ranged between 5.0 and 11.6%, in comparison with 1.9 to 3.2% when flow cytometry analysis was used. Besides, it is possible to conclude that the methods based on colored compounds presented lower precision to study the effect of propolis on biofilm properties. Therefore, we recommend the use of flow cytometry and confocal microscopy in S. mutans biofilm analysis.

scholarly journals Protein A-Mediated Multicellular Behavior in Staphylococcus aureus

2008 ◽  
Vol 191 (3) ◽  
pp. 832-843 ◽  
Author(s):  
Nekane Merino ◽  
Alejandro Toledo-Arana ◽  
Marta Vergara-Irigaray ◽  
Jaione Valle ◽  
Cristina Solano ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Protein A ◽  
Surface Proteins ◽  
Growth Media ◽  
Dependent Manner ◽  
Chronic Infections ◽  
The Matrix ◽  
Implanted Medical Devices ◽  
Biofilm Development

ABSTRACT The capacity of Staphylococcus aureus to form biofilms on host tissues and implanted medical devices is one of the major virulence traits underlying persistent and chronic infections. The matrix in which S. aureus cells are encased in a biofilm often consists of the polysaccharide intercellular adhesin (PIA) or poly-N-acetyl glucosamine (PNAG). However, surface proteins capable of promoting biofilm development in the absence of PIA/PNAG exopolysaccharide have been described. Here, we used two-dimensional nano-liquid chromatography and mass spectrometry to investigate the composition of a proteinaceous biofilm matrix and identified protein A (spa) as an essential component of the biofilm; protein A induced bacterial aggregation in liquid medium and biofilm formation under standing and flow conditions. Exogenous addition of synthetic protein A or supernatants containing secreted protein A to growth media induced biofilm development, indicating that protein A can promote biofilm development without being covalently anchored to the cell wall. Protein A-mediated biofilm formation was completely inhibited in a dose-dependent manner by addition of serum, purified immunoglobulin G, or anti-protein A-specific antibodies. A murine model of subcutaneous catheter infection unveiled a significant role for protein A in the development of biofilm-associated infections, as the amount of protein A-deficient bacteria recovered from the catheter was significantly lower than that of wild-type bacteria when both strains were used to coinfect the implanted medical device. Our results suggest a novel role for protein A complementary to its known capacity to interact with multiple immunologically important eukaryotic receptors.

scholarly journals Candida guilliermondii Complex Is Characterized by High Antifungal Resistance but Low Mortality in 22 Cases of Candidemia

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Laura Judith Marcos-Zambrano ◽  
Mireia Puig-Asensio ◽  
Felipe Pérez-García ◽  
Pilar Escribano ◽  
Carlos Sánchez-Carrillo ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Sensu Stricto ◽  
Candida Guilliermondii ◽  
Molecular Techniques ◽  
Content Type ◽  
Content Model ◽  
Crystal Violet Assay

ABSTRACT The objectives of our study were to describe the characteristics of patients with Candida guilliermondii candidemia and to perform an in-depth microbiological characterization of isolates and compare them with those of patients with C. albicans candidemia. We described the risk factors and outcomes of 22 patients with candidemia caused by the C. guilliermondii complex. Incident isolates were identified using molecular techniques, and susceptibility to fluconazole, anidulafungin, and micafungin was studied. Biofilm formation was measured using the crystal violet assay (biomass production) and the XTT reduction assay (metabolic activity), and virulence was studied using the Galleria mellonella model. Biofilm formation was compared with that observed for C. albicans. The main conditions predisposing to infection were malignancy (68%), immunosuppressive therapy (59%), and neutropenia (18%). Clinical presentation of candidemia was less severe in patients infected by the C. guilliermondii complex than in patients infected by C. albicans, and 30-day mortality was lower in C. guilliermondii patients (13.6% versus 33.9%, respectively; P = 0.049). Isolates were identified as C. guilliermondii sensu stricto (n = 17) and Candida fermentati (n = 5). The isolates produced biofilms with low metabolic activity and moderate biomass. The G. mellonella model showed that C. guilliermondii was less virulent than C. albicans (mean of 6 days versus 1 day of survival, respectively; P < 0.001). Patients with candidemia caused by the C. guilliermondii complex had severe and debilitating underlying conditions. Overall, the isolates showed diminished susceptibility to fluconazole and echinocandins, although poor biofilm formation and the low virulence were associated with a favorable outcome.

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