scholarly journals Trichosporon asahii and Trichosporon inkin Biofilms Produce Antifungal-Tolerant Persister Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Rossana de Aguiar Cordeiro ◽  
Ana Luiza Ribeiro Aguiar ◽  
Bruno Nascimento da Silva ◽  
Lívia Maria Galdino Pereira ◽  
Fernando Victor Monteiro Portela ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Growth Control ◽  
Persister Cells ◽  
Biofilm Growth ◽  
Trichosporon Asahii ◽  
Microbial Biofilms ◽  
Microtiter Plates ◽  
Trichosporon Inkin ◽  
Dormant Cells ◽  
High Doses

Persister cells are metabolically inactive dormant cells that lie within microbial biofilms. They are phenotypic variants highly tolerant to antimicrobials and, therefore, associated with recalcitrant infections. In the present study, we investigated if Trichosporon asahii and T. inkin are able to produce persister cells. Trichosporon spp. are ubiquitous fungi, commonly found as commensals of the human skin and gut microbiota, and have been increasingly reported as agents of fungemia in immunocompromised patients. Biofilms derived from clinical strains of T asahii (n=5) and T. inkin (n=7) were formed in flat-bottomed microtiter plates and incubated at 35°C for 48 h, treated with 100 μg/ml amphotericin B (AMB) and incubated at 35°C for additional 24 h. Biofilms were scraped from the wells and persister cells were assayed for susceptibility to AMB. Additionally, we investigated if these persister cells were able to generate new biofilms and studied their ultrastructure and AMB susceptibility. Persister cells were detected in both T asahii and T. inkin biofilms and showed tolerance to high doses of AMB (up to 256 times higher than the minimum inhibitory concentration). Persister cells were able to generate biofilms, however they presented reduced biomass and metabolic activity, and reduced tolerance to AMB, in comparison to biofilm growth control. The present study describes the occurrence of persister cells in Trichosporon spp. and suggests their role in the reduced AMB susceptibility of T. asahii and T. inkin biofilms.

scholarly journals Transcription Factors of CAT1, EFG1, and BCR1 Are Effective in Persister Cells of Candida albicans-Associated HIV-Positive and Chemotherapy Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Elham Aboualigalehdari ◽  
Maryam Tahmasebi Birgani ◽  
Mahnaz Fatahinia ◽  
Mehran Hosseinzadeh
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Agents ◽  
Rna Extraction ◽  
Persister Cells ◽  
Biofilm Growth ◽  
Microdilution Method ◽  
The Mean ◽  
High Doses ◽  
Chemotherapy Patients ◽  
Biofilm Development

BackgroundBiofilm is an accumulation of cells, which are formed on mucosal surfaces of the host as well as on medical devices. The inherent resistance of Candida strains producing biofilms to antimicrobial agents is an important and key feature for biofilm growth, which can lead to treatment failure. This resistance is due to the regulatory increase of the output pumps, the presence of extracellular matrix, and the existence of persister cells. Persister cells are phenotypic variants that have MICs similar to antibiotic-sensitive populations and are able to tolerate high doses of antibiotics. The current study investigated the possible role of EFG1, BCR1, and CAT1 in the establishment or maintenance of persister cells in Candida albicans strains that produce biofilms.MethodsAfter identifying Candida isolates by molecular methods, C. albicans isolates were confirmed by sequencing. Isolation of persister cells and determination of their MIC were performed by microdilution method. Then, RNA extraction and cDNA synthesis were performed from 60 C. albicans isolates under promoting and inducing conditions. Afterward, the mean expression of BCR1, EFG1, and CAT1 genes in both persister and non-persister groups was calculated using real-time qPCR. Phylogeny tree of persister and non-persister group isolates was drawn using ITS fragment.ResultsA total of 77 persister isolates were taken from the oral cavity of HIV patients as well as from patients undergoing chemotherapy. Biofilm intensity in persister isolates separated from HIV-infected patients was different from the non-persister group. The mean fold change of BCR1 (10.73), CAT1 (15.34), and EFG1 (2.41) genes in persister isolates was significantly higher than these genes in isolates without persister.ConclusionIt can be concluded that the most important factor in the production of persister cells is biofilm binding and production, not biofilm development or mature biofilm production, which was found in the expression of BCR1 gene without change in the expression of EFG1 gene in the persister group. Also, catalase plays an essential role in the production of persister in C. albicans biofilm producers with ROS detoxification.

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 The Effect of Gold and Iron-Oxide Nanoparticles on Biofilm-Forming Pathogens

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Madhu Bala Sathyanarayanan ◽  
Reneta Balachandranath ◽  
Yuvasri Genji Srinivasulu ◽  
Sathish Kumar Kannaiyan ◽  
Guruprakash Subbiahdoss
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Immune Cells ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Medical Applications ◽  
Oxide Nanoparticles ◽  
Biofilm Growth ◽  
Microbial Biofilms ◽  
Exopolymeric Substances

Microbial biofilms on biomaterial implants or devices are hard to eliminate by antibiotics due to their protection by exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune-cells. Application of metals in their nanoparticulated form is currently considered to resolve bacterial infections. Gold and iron-oxide nanoparticles are widely used in different medical applications, but their utilisation to eradicate biofilms on biomaterials implants is novel. Here, we studied the effect of gold and iron oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa biofilms. We report that biofilm growth was reduced at higher concentrations of gold and iron-oxide nanoparticles compared to absence of nanoparticles. Thus nanoparticles with appropriate concentration could show significant reduction in biofilm formation.

scholarly journals Effects of pipe materials on biofouling under controlled hydrodynamic conditions

2015 ◽  
Vol 6 (1) ◽  
pp. 167-174 ◽  
Author(s):  
S. Gamri ◽  
A. Soric ◽  
S. Tomas ◽  
B. Molle ◽  
N. Roche
Keyword(s):  
Growth Control ◽  
Surface Characteristics ◽  
Primary Role ◽  
Pipe Material ◽  
Hydrodynamic Conditions ◽  
Biofilm Growth ◽  
Pipe Surface ◽  
Biofilm Detachment ◽  
Pvc Pipe ◽  
Pipe Materials

Experiments were carried out to investigate pipe material impacts on biofouling, at high effluent concentration levels and under controlled hydrodynamic conditions. Two velocities (0.4 and 0.8 m s−1) were used to monitor biofilm growth on polyethylene (PE) and polyvinylchloride (PVC) pipe walls, respectively. These conditions were established based on wastewater irrigation practices. A decrease in biomass is observed after 49 days of experiments for both velocities and may be related to biofilm detachment. Biofilm growth is greater at 0.8 m s−1. For both velocities, PVC is less sensitive to biofilm growth than PE. Pipe straightness plays a primary role in biofilm growth control. This effect is more significant than pipe surface characteristics (roughness, hydrophobic/hydrophilic properties).

scholarly journals Head-to-Head Comparison of Inhibitory and Fungicidal Activities of Fluconazole, Itraconazole, Voriconazole, Posaconazole, and Isavuconazole against Clinical Isolates of Trichosporon asahii

2013 ◽  
Vol 57 (10) ◽  
pp. 4841-4847 ◽  
Author(s):  
Gulsen Hazirolan ◽  
Emilia Canton ◽  
Selma Sahin ◽  
Sevtap Arikan-Akdagli
Keyword(s):  
Rank Order ◽  
Growth Control ◽  
Clinical Isolates ◽  
Content Type ◽  
Trichosporon Asahii ◽  
Killing Activity ◽  
Fungistatic Activity ◽  
Microdilution Method ◽  
Inhibition Of Growth ◽  
Time Kill

ABSTRACTTreatment of disseminatedTrichosporoninfections still remains difficult. Amphotericin B frequently displays inadequate fungicidal activity and echinocandins have no meaningful antifungal effect against this genus. Triazoles are currently the drugs of choice for the treatment ofTrichosporoninfections. This study evaluates the inhibitory and fungicidal activities of five triazoles against 90 clinical isolates ofTrichosporon asahii. MICs (μg/ml) were determined according to Clinical and Laboratory Standards Institute microdilution method M27-A3 at 24 and 48 h using two endpoints, MIC-2 and MIC-0 (the lowest concentrations that inhibited ∼50 and 100% of growth, respectively). Minimum fungicidal concentrations (MFCs; μg/ml) were determined by seeding 100 μl of all clear MIC wells (using an inoculum of 104CFU/ml) onto Sabouraud dextrose agar. Time-kill curves were assayed against four clinicalT. asahiiisolates and theT. asahiiATCC 201110 strain. The MIC-2 (∼50% reduction in turbidity compared to the growth control well)/MIC-0 (complete inhibition of growth)/MFC values that inhibited 90% of isolates at 48 h were, respectively, 8/32/64 μg/ml for fluconazole, 1/2/8 μg/ml for itraconazole, 0.12/0.5/2 μg/ml for voriconazole, 0.5/2/4 μg/ml for posaconazole, and 0.25/1/4 μg/ml for isavuconazole. The MIC-0 endpoints yielded more consistent MIC results, which remained mostly unchanged when extending the incubation to 48 h (98 to 100% agreement with 24-h values) and are easier to interpret. Based on the time-kill experiments, none of the drugs reached the fungicidal endpoint (99.9% killing), killing activity being shown but at concentrations not reached in serum. Statistical analysis revealed that killing rates are dose and antifungal dependent. The lowest concentration at which killing activity begins was for voriconazole, and the highest was for fluconazole. These results suggest that azoles display fungistatic activity and lack fungicidal effect againstT. asahii. By rank order, the most active triazole is voriconazole, followed by itraconazole ∼ posaconazole ∼ isavuconazole > fluconazole.

Effect of Human Milk and its Components on Streptococcus Mutans Biofilm Formation

2015 ◽  
Vol 39 (3) ◽  
pp. 255-261 ◽  
Author(s):  
LM Allison ◽  
LA Walker ◽  
BJ Sanders ◽  
Z Yang ◽  
G Eckert ◽  
...  
Keyword(s):  
Breast Milk ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Current Knowledge ◽  
Post Partum ◽  
Human Breast Milk ◽  
Human Breast ◽  
Flat Bottom ◽  
Biofilm Growth ◽  
Microtiter Plates

Objective: This study investigated the effects of human breast milk and its components on the nutritional aspect of the caries process due to Streptococcus mutans UA159 biofilm formation. Study design: Human breast milk was collected from 11 mothers during 3-9 months postpartum. To test for the effect on biofilm formation, a 16-hour culture of S. mutans was treated with dilutions of human breast milk and several major components of human breast milk, lactose, lactoferrin, IgA, and bovine casein in sterile 96-well flat bottom microtiter plates for 24 hours. The biofilms were fixed, washed, stained with crystal violet, and extracted. Absorbance was measured to evaluate biofilm growth mass. Results: Dilutions 1:10-1:2,560 of the human breast milk samples increased biofilm formation by 1.5-3.8 fold compared to the control. Lactoferrin decreased biofilm formation significantly in all dilutions (average milk concentration of 3 mg/ml). Lactose had no effect at average breast milk concentrations (60 mg/ml) except at its lowest concentration (15 mg/ml) where it was increased. IgA significantly decreased biofilm formation at its highest concentration of 2,400 μg/ml (average milk concentration 600 μg/ml). Casein caused significantly increased biofilm formation at all concentrations tested above the average milk content (2.3 mg/ml). Conclusions: The results of this study demonstrate an increase in S. mutans biofilm formation by human breast milk 3-9 months post partum. Among its major components, only casein significantly increased biofilm formation among the concentrations analyzed. Lactose had no effect except at 15 mg/ml. Lactoferrin and IgA significantly decreased S. mutans biofilm formation at their highest concentrations. This information expands the current knowledge regarding the nutritional influence of breastfeeding and validates the necessity to begin an oral hygiene regimen once the first tooth erupts.

Antibodies against lepirudin are polyspecific and recognize epitopes on bivalirudin

Blood ◽  
2004 ◽  
Vol 103 (2) ◽  
pp. 613-616 ◽  
Author(s):  
Petra Eichler ◽  
Norbert Lubenow ◽  
Ulrike Strobel ◽  
Andreas Greinacher
Keyword(s):  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Testing ◽  
Recombinant Hirudin ◽  
Elisa System ◽  
Microtiter Plates ◽  
Clinical Consequences ◽  
High Concentrations ◽  
Clinically Significant ◽  
High Doses

Abstract Bivalirudin is a synthetic antithrombin sharing a sequence of 11 amino acids with the recombinant hirudin lepirudin. We investigated whether antilepirudin antibodies recognize epitopes on bivalirudin. Antilepirudin antibody–positive sera of 43 patients, treated with lepirudin for heparin-induced thrombocytopenia, were analyzed. Lepirudin- and bivalirudin-coated microtiter plates were used for antibody testing in an enzyme-linked immunosorbent assay (ELISA) system. Of the 43 sera-containing antibodies binding to lepirudin, 22 (51.2%) contained antibodies that also recognized bivalirudin. Binding of these antibodies to bivalirudin was inhibited by more than 70% by preincubation with high doses of bivalirudin. However, if lepirudin-coated microtiter plates were used, high concentrations of bivalirudin inhibited only 2 of the 43 positive sera by more than 30%. Therefore antihirudin antibodies must be polyspecific. The clinical consequences of this cross-reactivity are unknown but bivalirudin, targeted by antibodies of patients treated with lepirudin previously, could potentially boost antibody titers in such patients or even trigger an immune response by itself. Clinically significant antibody formation in response to bivalirudin monotherapy has not been observed, however. Yet, as lepirudin and antilepirudin antibodies have recently been implicated in severe anaphylactic reactions, caution is warranted when using bivalirudin in patients previously treated with lepirudin.

scholarly journals In vitro evaluation of the antimicrobial activity of Basil (Ocimum baslicum L.) and Coriander (Coriandrum satirum L.) oil extracts on Streptococus mutans

2018 ◽  
Vol 5 (2) ◽  
pp. 40 ◽  
Author(s):  
Mariana Lourenço ◽  
Adilson Cesar Abreu Bernardi ◽  
Nadia Lunardi ◽  
Rodolfo Jorge Boeck Neto ◽  
Patricia Sigilló Mazzoni Bernardi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Minimum Inhibitory Concentration ◽  
Plant Extracts ◽  
Inhibitory Activity ◽  
Inhibitory Concentration ◽  
Growth Control ◽  
Ocimum Basilicum ◽  
Coriandrum Sativum ◽  
Microdilution Method

Plant extracts and essential oils show efficiency on growth control in a wide variation of microorganisms, including filamentous fungi, yeasts and bacteria. To evaluate antimicrobial activity of plant extracts, determine the lower quantity of substance to inhibit the microorganism test growth is necessary. This value is known as Minimum Inhibitory Concentration (MIC). This study had as aim to verify the antimicrobial action and the Minimum Inhibitory Concentration (MIC) of basil (Ocimum basilicum L.) and coriander (Coriandrum sativum L.) oil extract before S. mutans (ATCC 25175) strains. Antimicrobial activity determination was carried out by microdilution method and performed according to recommendations of CLSI (previously known as NCCLS), standard M7-A6 (NCCLS, 2003) for bacteria, and standard M27-A2 (NCCLS, 2002). All the experiments were carried out in triplicate. Results showed the Minimum Inhibitory Concentration (MIC) determination by microdilution method in broth showed Ocimum basilicum L. and Coriandrum sativum L. extract oils presented inhibitory activity before S. mutans strain. Basil in 1:4 concentration is bacteriostatic and in 1:3 concentration is bactericide. Coriander in 1:2 concentration is bacteriostatic and in 1:1 concentration is bactericide. We concluded that basil presented higher inhibitory activity regarding to the coriander. We also observed as bigger the extract dilution, lower their effectivity.o assess the attitude and practice of dental professionals towards using of advance Radiographic technique.

scholarly journals The Mce3R stress-resistance pathway is vulnerable to small-molecule targeting that improves tuberculosis drug activities

2019 ◽  
Author(s):  
Xinxin Yang ◽  
Tianao Yuan ◽  
Rui Ma ◽  
Kieran Chacko ◽  
Melissa Smith ◽  
...  
Keyword(s):  
Small Molecule ◽  
Stress Resistance ◽  
Inhibitory Concentration ◽  
Infectious Agent ◽  
Low Oxygen ◽  
Long Duration ◽  
Resistance Pathway ◽  
Oxygen Conditions ◽  
Drug Regimens ◽  
High Doses

<p>One-third of the world’s population carries <i>Mycobacterium tuberculosis </i>(<i>Mtb</i>), the infectious agent that causes tuberculosis (TB), and every 17 seconds someone dies of TB. After infection, <i>Mtb</i>can live dormant within macrophages for decades in a granuloma structure arising from the host immune response; and cholesterol is important for this persistence of <i>Mtb</i>. Current treatments require long-duration drug regimens with many associated toxicities, which are compounded by the high doses required. We phenotypically screened 35 6-azasteroid analogues against <i>Mtb</i>and found that at low micromolar concentrations, a subset of the <a>analogues sensitized <i>Mtb</i></a>to multiple TB drugs. Two analogues were selected for further study to characterize the bactericidal activity of bedaquiline and isoniazid under normoxic and low-oxygen conditions. These two 6-azasteroids <a>showed strong synergy with bedaquiline</a>(fractional inhibitory concentration index = 0.21, bedaquiline minimal inhibitory concentration = 16 nM at 1 μM 6-azasteroid). The rate at which spontaneous resistance to one of the 6-azasteroids arose in the presence of bedaquiline was approximately 10<sup>−9</sup>, and the 6-azasteroid-resistant mutants retained their isoniazid and bedaquiline sensitivity. Genes in the cholesterol-regulated Mce3R regulon were required for 6-azasteroid activity, whereas genes in the cholesterol catabolism pathway were not. Expression of a subset of Mce3R genes was down-regulated upon 6-azasteroid treatment. The Mce3R regulon is implicated in stress resistance and is absent in saprophytic mycobacteria. This regulon encodes a cholesterol-regulated stress-resistance pathway that we conclude is important for pathogenesis and contributes to drug tolerance, and that this pathway is vulnerable to small-molecule targeting in live mycobacteria.</p>

scholarly journals Environmental conditions define the energetics of bacterial dormancy and its antibiotic susceptibility

2020 ◽  
Author(s):  
L Mancini ◽  
T Pilizota
Keyword(s):  
Drug Susceptibility ◽  
Cell Physiology ◽  
Environmental Cues ◽  
Bacterial Cells ◽  
Infection Site ◽  
Persister Cells ◽  
Energy Profiles ◽  
Dormant Cells ◽  
Clinical Interest ◽  
High Concentrations

ABSTRACTBacterial cells that halt growth but maintain viability and the capacity to regrow are termed dormant and have been shown to transiently tolerate high concentrations of antimicrobials. Dormancy has been seen in both tolerant and persister cells and is therefore of substantial clinical interest, as both can lead to infection recalcitrance and facilitate the development of antibiotic resistance. In this work, we look at dormancies induced by environmental cues that target different aspects of cell physiology by measuring the energy profiles they elicit in single dormant cells. Our simultaneous measurements of ATP concentration, proton motive force (PMF) and cytoplasmic pH reveal that dormant cells can exist in various energy states, offering a solution to the apparent mutual incompatibility of previous experimental results. We then test whether the energetic makeup is associated with survival to antibiotics of different classes. We find that for certain drugs growth arrest remains the dominant mechanism enabling survival, while for others, like ciprofloxacin, the most energetic cells remain almost untouched by the drug. Our results support a novel relationship between environment and drug susceptibility of dormant cells and suggest that knowledge of the conditions present at the infection site is necessary to design appropriate treatments.

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