scholarly journals Saccharide sources do not influence the biofilm formation in Scedosporium/Lomentospora species

2020 ◽  
Vol 1 ◽  
Author(s):  
Thaís Pereira de Mello ◽  
Marta Helena Branquinha ◽  
André Luis Souza dos Santos
Keyword(s):  
Biofilm Formation ◽  
Culture Media ◽  
Yeast Nitrogen Base ◽  
Human Pathogens ◽  
Nitrogen Base ◽  
Opportunistic Fungi ◽  
Abiotic Surfaces ◽  
Resistance Patterns ◽  
Almost All ◽  
Glucose Supplementation

Abstract Scedosporium and Lomentospora species are ubiquitous saprophytic filamentous fungi that emerged as human pathogens with impressive multidrug-resistance profile. The ability to form biofilm over several biotic and abiotic surfaces is one of the characteristics that contributes to their resistance patterns against almost all currently available antifungals. Herein, we have demonstrated that Scedosporium apiospermum, Scedosporium minutisporum, Scedosporium aurantiacum and Lomentospora prolificans were able to form biofilm, in similar amounts, when conidial cells were incubated in a polystyrene substrate containing Sabouraud medium supplemented or not with different concentrations (2%, 5% and 10%) of glucose, fructose, sucrose and lactose. Likewise, the glucose supplementation of culture media primarily composed of amino acids (SCFM, synthetic cystic fibrosis medium) and salts (YNB, yeast nitrogen base) did not modulate the biofilm formation of Scedosporium/Lomentospora species. Collectively, the present data reinforce the ability of these opportunistic fungi to colonize and to build biofilm structures under different environmental conditions.

Biofilm formation by Xanthomonas campestris pv. viticola affected by abiotic surfaces and culture media

2017 ◽  
Vol 43 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Myrzânia L. Guerra ◽  
Carolina B. Malafaia ◽  
Alexandre J. Macedo ◽  
Márcia V. Silva ◽  
Rosa L. R. Mariano ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Xanthomonas Campestris ◽  
Culture Media ◽  
Abiotic Surfaces

scholarly journals Insulin Regulation of Escherichia coli Abiotic Biofilm Formation: Effect of Nutrients and Growth Conditions

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1349
Author(s):  
Nina Patel ◽  
Jeremy C. Curtis ◽  
Balbina J. Plotkin
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Fold Increase ◽  
Growth Conditions ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
E Coli ◽  
Biofilm Production ◽  
Mueller Hinton ◽  
Static Conditions

Escherichia coli plays an important role in biofilm formation across a wide array of disease and ecological settings. Insulin can function as an adjuvant in the regulation of biofilm levels. The modulation of insulin-regulated biofilm formation by environmental conditions has not been previously described. In the present study, the effects that various environmental growth conditions and nutrients have on insulin-modulated levels of biofilm production were measured. Micropipette tips were incubated with E. coli ATCC® 25922™ in a Mueller Hinton broth (MH), or a yeast nitrogen base with 1% peptone (YNBP), which was supplemented with glucose, lactose, galactose and/or insulin (Humulin®-R). The incubation conditions included a shaking or static culture, at 23 °C or 37 °C. After incubation, the biofilm production was calculated per CFU. At 23 °C, the presence of insulin increased biofilm formation. The amount of biofilm formation was highest in glucose > galactose >> lactose, while the biofilm levels decreased in shaking cultures, except for galactose (3-fold increase; 0.1% galactose and 20 μU insulin). At 37 °C, regardless of condition, there was more biofilm formation/CFU under static conditions in YNBP than in MH, except for the MH containing galactose. E. coli biofilm formation is influenced by aeration, temperature, and insulin concentration in combination with the available sugars.

Improved blood culture medium for radiometric detection of yeasts

1979 ◽  
Vol 9 (3) ◽  
pp. 448-449
Author(s):  
R L Hopfer ◽  
K Mills ◽  
D Gröschel
Keyword(s):  
Blood Culture ◽  
Culture Medium ◽  
Culture Media ◽  
Medium Composition ◽  
Co2 Production ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
System A ◽  
Radiometric Detection ◽  
Triton X

The influence of medium composition on the rate of CO2 production by yeasts in simulated blood cultures was determined in the Bactec radiometric system. A yeast nitrogen base broth containing [14C]glucose and Triton X-100 allowed the detection of positive cultures earlier than the regular Bactec blood culture media.

scholarly journals Influence of Shaking on Antifungal Susceptibility Testing of Cryptococcus neoformans: a Comparison of the NCCLS Standard M27A Medium, Buffered Yeast Nitrogen Base, and RPMI–2% Glucose

2000 ◽  
Vol 44 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Juan L. Rodríguez-Tudela ◽  
Francisco Martín-Díez ◽  
Manuel Cuenca-Estrella ◽  
Laura Rodero ◽  
Yolanda Carpintero ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Clinical Laboratory ◽  
Culture Media ◽  
Antifungal Susceptibility ◽  
Optimal Growth ◽  
Inoculum Size ◽  
National Committee ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Antifungal Susceptibility Test

ABSTRACT Cryptococcus neoformans is a nonfermentative yeast that requires oxygen for growth. The shaking of culture media achieves good oxygenation, promoting the growth of cryptococci. In this study, three test media (RPMI 1640, RPMI 1640–2% glucose, and buffered yeast nitrogen base [BYNB]) recommended in the National Committee for Clinical Laboratory Standards M27A standard were examined. Growth abilities and minimum inhibitory concentrations (MICs) in microplates incubated at 35°C for 48 h were determined. The results indicated that shaking and an inoculum size of 105 CFU/ml yielded optimal growth of this yeast. Compared to RPMI 1640, supplementation of RPMI 1640 with 2% glucose did not significantly improve growth of C. neoformans and resulted in an 8.7-h delay of exponential growth. Cryptococcal growth in RPMI 1640 at 24 h was notably better than that in RPMI–2% glucose, although by 48 h the growths were comparable. The MIC range of amphotericin B observed for the C. neoformans strains grown in RPMI 1640 with or without glucose was too narrow to allow the separation of susceptible and resistant strains based on clinical outcome. The widest ranges of MICs of flucytosine and fluconazole were obtained with BYNB. This work demonstrates the need for a new antifungal susceptibility test for C. neoformans.

scholarly journals D-Fructose Assimilation and Fermentation by Yeasts Belonging to Saccharomycetes: Rediscovery of Universal Phenotypes and Elucidation of Fructophilic Behaviors in Ambrosiozyma platypodis and Cyberlindnera americana

2021 ◽  
Vol 9 (4) ◽  
pp. 758
Author(s):  
Rikiya Endoh ◽  
Maiko Horiyama ◽  
Moriya Ohkuma
Keyword(s):  
Yeast Species ◽  
Yeast Nitrogen Base ◽  
Sugar Consumption ◽  
Nitrogen Base ◽  
Physiological Properties ◽  
Standard Set ◽  
Durham Tube ◽  
Ascomycetous Yeasts ◽  
Almost All ◽  
Ubiquitous Presence

The purpose of this study was to investigate the ability of ascomycetous yeasts to assimilate/ferment d-fructose. This ability of the vast majority of yeasts has long been neglected since the standardization of the methodology around 1950, wherein fructose was excluded from the standard set of physiological properties for characterizing yeast species, despite the ubiquitous presence of fructose in the natural environment. In this study, we examined 388 strains of yeast, mainly belonging to the Saccharomycetes (Saccharomycotina, Ascomycota), to determine whether they can assimilate/ferment d-fructose. Conventional methods, using liquid medium containing yeast nitrogen base +0.5% (w/v) of d-fructose solution for assimilation and yeast extract-peptone +2% (w/v) fructose solution with an inverted Durham tube for fermentation, were used. All strains examined (n = 388, 100%) assimilated d-fructose, whereas 302 (77.8%) of them fermented d-fructose. In addition, almost all strains capable of fermenting d-glucose could also ferment d-fructose. These results strongly suggest that the ability to assimilate/ferment d-fructose is a universal phenotype among yeasts in the Saccharomycetes. Furthermore, the fructophilic behavior of Ambrosiozyma platypodis JCM 1843 and Cyberlindnera americana JCM 3592 was characterized by sugar consumption profiles during fermentation.

In Vitro Evaluation of Candida albicans Biofilm Formation on Denture Base PMMA Resin Incorporated with Silver Nanoparticles and its Effect on Flexural Strength

2014 ◽  
Vol 905 ◽  
pp. 51-55 ◽  
Author(s):  
Sahana Bajracharya ◽  
Sroisiri Thaweboon ◽  
Boonyanit Thaweboon ◽  
Amornrat Wonglamsam ◽  
Theerathavaj Srithavaj
Keyword(s):  
Silver Nanoparticles ◽  
Flexural Strength ◽  
Biofilm Formation ◽  
Base Material ◽  
Bending Test ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Denture Base ◽  
Pmma Resin

The aim of this study is to investigate the candidal biofilm formation on the silver nanoparticles (AgNPs) incorporated denture base heat-polymerized (poly methyl methacrylate), PMMA, resinand its flexural strength.Materials and methods:A total of 36PMMA resin specimens (15×15×2 mm3) were fabricated and divided into 4 groups based on their AgNPs contents (0%,0.5%, 1% and 1.5% w/w of polymer). The biofilm of clinical and reference strainsof C.albicanswere grown on PMMA resin specimens in the presence of yeast nitrogen base broth supplemented with 100 mM glucose at 37oC for 48 h and evaluated by tetrazolium reduction assay. The flexural strength of PMMA resin specimens (65×10×3.3 mm3) were tested by using three-point bending test. Data were analyzed by Kruskal-Wallis and Mann-Whitney U test at p<0.05. result:all="" 3="" groups="" with="" agnps="" showed="" significant="" reduction="" in="" biofilm="" formation="" of="" both="" strains="" i="">C.albicans compared to control (0% AgNPs) (p<0.05). Decreased flexural strength was observed with AgNPs groups compared with the control but within acceptable limit of ISO 20795-1. Conclusion:The reduction of the C. albicans biofilm was observed on the heat-polymerized PMMA resin incorporated with AgNPs. Regarding the flexural strength, the values were within ISO limit. These modified PMMA resin can be developed for the prevention or treatment of the candidal infection associated with the denture base material.

scholarly journals Evaluation of Biofilm Formation in Candida tropicalis Using a Silicone-Based Platform with Synthetic Urine Medium

2020 ◽  
Vol 8 (5) ◽  
pp. 660 ◽  
Author(s):  
Yi-Kai Tseng ◽  
Yu-Chia Chen ◽  
Chien-Jui Hou ◽  
Fu-Sheng Deng ◽  
Shen-Huan Liang ◽  
...  
Keyword(s):  
Candida Tropicalis ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Culture Conditions ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Biofilm Growth ◽  
Synthetic Urine ◽  
Regulatory Circuits ◽  
Gene Mutant

Molecular mechanisms of biofilm formation in Candida tropicalis and current methods for biofilm analyses in this fungal pathogen are limited. (2) Methods: Biofilm biomass and crystal violet staining of the wild-type and each gene mutant strain of C. tropicalis were evaluated on silicone under synthetic urine culture conditions. (3) Results: Seven media were tested to compare the effects on biofilm growth with or without silicone. Results showed that biofilm cells of C. tropicalis were unable to form firm biofilms on the bottom of 12-well polystyrene plates. However, on a silicone-based platform, Roswell Park Memorial Institute 1640 (RPMI 1640), yeast nitrogen base (YNB) + 1% glucose, and synthetic urine media were able to induce strong biofilm growth. In particular, replacement of Spider medium with synthetic urine in the adherence step and the developmental stage is necessary to gain remarkably increased biofilms. Interestingly, unlike Candida albicans, the C. tropicalis ROB1 deletion strain but not the other five biofilm-associated mutants did not cause a significant reduction in biofilm formation, suggesting that the biofilm regulatory circuits of the two species are divergent. (4) Conclusions: This system for C. tropicalis biofilm analyses will become a useful tool to unveil the biofilm regulatory network in C. tropicalis.

The size of extracellular vesicles secreted by different types of stem cells

2018 ◽  
pp. 38-42
Author(s):  
И.Б. Алчинова ◽  
М.В. Полякова ◽  
И.Н. Сабурина ◽  
М.Ю. Карганов
Keyword(s):  
Stem Cells ◽  
Extracellular Vesicles ◽  
Culture Media ◽  
Living Organism ◽  
Isolation And Characterization ◽  
Transmission Electron ◽  
Study Results ◽  
Multipotent Mesenchymal Stem Cells ◽  
Rat Adipose Tissue ◽  
Almost All

Механизм терапевтического действия мультипотентных мезенхимных стволовых клеток (ММСК) на облученный организм в последнее время вызывает повышенный интерес исследователей. В качестве активного участника паракринного механизма реализации этого эффекта предлагают рассматривать внеклеточные везикулы, секретируемые практически всеми клетками живого организма. Цель работы: выделить и охарактеризовать внеклеточные везикулы, продуцируемые стволовыми клетками различной природы. Материалы и методы. Суспензии внеклеточных везикул, выделенных по модифицированному протоколу дифференциального центрифугирования из культуральных жидкостей от культур ММСК костного мозга человека 2-го пассажа и ММСК жировой ткани крысы 4-го пассажа, были проанализированы методом просвечивающей электронной микроскопии и методом анализа траекторий наночастиц. Результаты. Исследование показало наличие в обоих образцах микрочастиц размерами до и около 100 нм, однако процентное содержание частиц разных размеров в суспензии различалось для двух анализируемых типов клеток. Заключение. Полученные результаты могут свидетельствовать о специфике секреции, обусловленной клеточным типом. A mechanism of the therapeutic effect of multipotent mesenchymal stem cells (MMSC) on irradiated body has recently arisen much interest of researchers. Extracellular vesicles (EVs) secreted by almost all cells of a living organism were suggested to actively contribute to the paracrine mechanism of this effect. The aim of the study was isolation and characterization of extracellular vesicles produced by various types of stem cells. Materials and methods. Suspensions of EVs were isolated from culture media of passage 2 human bone marrow-derived MMSC and passage 4 rat adipose tissue-derived MMSC using a modified protocol of differential centrifugation and then studied using transmission electron microscopy and nanoparticle tracking analysis. Results. The study showed the presence of microparticles with a size of >100 nm in the examined samples. However, the percent content of particles with different sizes in the suspension was different in two analyzed types of cell culture. Conclusion. The study results might reflect a specificity of secretion determined by the cell type.

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

scholarly journals Surface Immobilization of Nano-Silver on Polymeric Medical Devices to Prevent Bacterial Biofilm Formation

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 93 ◽  
Author(s):  
Riau ◽  
Aung ◽  
Setiawan ◽  
Yang ◽  
Yam ◽  
...  
Keyword(s):  
Medical Devices ◽  
Biofilm Formation ◽  
Culture Media ◽  
Silver Ions ◽  
Bacterial Biofilm ◽  
Surface Immobilization ◽  
Nano Silver ◽  
Gram Positive Bacteria ◽  
Tissue Microenvironment

: Bacterial biofilm on medical devices is difficult to eradicate. Many have capitalized the anti-infective capability of silver ions (Ag+) by incorporating nano-silver (nAg) in a biodegradable coating, which is then laid on polymeric medical devices. However, such coating can be subjected to premature dissolution, particularly in harsh diseased tissue microenvironment, leading to rapid nAg clearance. It stands to reason that impregnating nAg directly onto the device, at the surface, is a more ideal solution. We tested this concept for a corneal prosthesis by immobilizing nAg and nano-hydroxyapatite (nHAp) on poly(methyl methacrylate), and tested its biocompatibility with human stromal cells and antimicrobial performance against biofilm-forming pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Three different dual-functionalized substrates—high Ag (referred to as 75:25 HAp:Ag); intermediate Ag (95:5 HAp:Ag); and low Ag (99:1 HAp:Ag) were studied. The 75:25 HAp:Ag was effective in inhibiting biofilm formation, but was cytotoxic. The 95:5 HAp:Ag showed the best selectivity among the three substrates; it prevented biofilm formation of both pathogens and had excellent biocompatibility. The coating was also effective in eliminating non-adherent bacteria in the culture media. However, a 28-day incubation in artificial tear fluid revealed a ~40% reduction in Ag+ release, compared to freshly-coated substrates. The reduction affected the inhibition of S. aureus growth, but not the P. aeruginosa. Our findings suggest that Ag+ released from surface-immobilized nAg diminishes over time and becomes less effective in suppressing biofilm formation of Gram-positive bacteria, such as S. aureus. This advocates the coating, more as a protection against perioperative and early postoperative infections, and less as a long-term preventive solution.

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