How to build a biofilm: a fungal perspective.
ABSTRACT Biofilms are differentiated masses of microbes that form on surfaces and are surrounded by an extracellular matrix. Fungal biofilms, especially those of the pathogen Candida albicans, are a cause of infections associated with medical devices. Such infections are particularly serious because biofilm cells are relatively resistant to many common antifungal agents. Several in vitro models have been used to elucidate the developmental stages and processes required for C. albicans biofilm formation, and recent studies have begun to define biofilm genetic control. It is clear that cell-substrate and cell-cell interactions, hyphal differentiation and extracellular matrix production are key steps in biofilm development. Drug resistance is acquired early in biofilm formation, and appears to be governed by different mechanisms in early and late biofilms. Quorum sensing might be an important factor in dispersal of biofilm cells. The past two years have seen the emergence of several genomic strategies to uncover global events in biofilm formation and directed studies to understand more specific events, such as hyphal formation, in the biofilm setting.
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ABSTRACT: The aim of the present study was to perform an in vitro analysis of the antimicrobial and antiproliferative potential of an extract from Anadenanthera colubrina (Vell.) Brenan (angico) and chemically characterize the crude extract. Antimicrobial action was evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration, and the inhibition of formation to oral biofilm. Cell morphology was determined through scanning electron microscopy (SEM). Six strains of tumor cells were used for the determination of antiproliferative potential. The extract demonstrated strong antifungal activity against Candida albicans ATCC 18804 (MIC = 0.031 mg/mL), with similar activity found regarding the ethyl acetate fraction. The extract and active fraction also demonstrated the capacity to inhibit the formation of Candida albicans to oral biofilm after 48 hours, with median values equal to or greater than the control group, but the difference did not achieve statistical significance (P > 0.05). SEM revealed alterations in the cell morphology of the yeast. Regarding antiproliferative activity, the extract demonstrated cytostatic potential in all strains tested. The present findings suggest strong antifungal potential for Anadenanthera colubrina (Vell.) Brenan as well as a tendency toward diminishing the growth of human tumor cells.Evidence-based Complementary and Alternative Medicine 06/2014; 2014:802696. DOI:10.1155/2014/802696 · 1.88 Impact Factor
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ABSTRACT: Mycobacterium bovis causes classic bovine tuberculosis, a zoonosis which is still a concern in Africa. Biofilm forming ability of two Mycobacterium bovis strains was assessed on coupons of cement, ceramic, or stainless steel in three different microbiological media at 37°C with agitation for 2, 3, or 4 weeks to determine the medium that promotes biofilm. Biofilm mass accumulated on coupons was treated with 2 sanitizers (sanitizer A (5.5 mg L(-1) active iodine) and sanitizer B (170.6 g(1) alkyl dimethylbenzyl ammonium chloride, 78 g(-1) didecyldimethyl ammonium chloride, 107.25 g L(-1) glutaraldehyde, 146.25 g L(-1) isopropanol, and 20 g L(-1) pine oil) at 28 and 45°C and in hot water at 85°C for 5 min. Residual biofilms on treated coupons were quantified using crystal violet binding assay. The two strains had a similar ability to form biofilms on the three surfaces. More biofilms were developed in media containing 5% liver extract. Biofilm mass increased as incubation time increased till the 3rd week. More biofilms were formed on cement than on ceramic and stainless steel surfaces. Treatment with hot water at 85°C reduced biofilm mass, however, sanitizing treatments at 45°C removed more biofilms than at 28°C. However, neither treatment completely eliminated the biofilms. The choice of processing surface and temperatures used for sanitizing treatments had an impact on biofilm formation and its removal from solid surfaces.BioMed Research International 06/2014; 2014:210165. DOI:10.1155/2014/210165 · 2.71 Impact Factor
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ABSTRACT: Candida albicans is the most prevalent human fungal pathogen associated with biofilm formation on indwelling medical devices. Under this form, Candida represents an infectious reservoir difficult to eradicate and possibly responsible for systemic, often lethal infections. Currently, no information is available on the occurrence and persistence of pathogenic viruses within C. albicans biofilm. Therefore, the aim of this study was to investigate whether Herpes Simplex Virus type 1 (HSV-1) and Coxsackievirus type B5 (CVB5) can be encompassed in Candida biofilm, retain their infectivity and then be released. Thus, cell-free virus inocula or HSV-1-infected cells were added to 24 h-old fungal biofilm in tissue culture plates; 48h later, the biofilm was detached by washing and energetic scratching and the presence of virus in the rescued material was end-point titrated on VERO cells. Planktonic Candida cultures and samples containing only medium were run in parallel as controls. We found that both HSV-1 and CVB5 free virus particles, as well as HSV-1 infected cells remain embedded in the biofilm retaining their infectivity. As a second step, the influence of biofilm on virus sensitivity to sodium hypochlorite and to specific neutralizing antibodies was investigated. The results showed that virus encompassment in fungal biofilm reduces virus sensitivity to chemical inactivation but does not affect antibody neutralization. Overall, these data provide the first in vitro evidence that viruses can be encompassed within Candida biofilm and then be released. Thus, it may be speculated that Candida biofilm can be a reservoir of viruses too, posing a further health risk.Virus Research 10/2013; 179. DOI:10.1016/j.virusres.2013.10.018 · 2.83 Impact Factor