scholarly journals Dectin-2-Targeted Antifungal Liposomes Exhibit Enhanced Efficacy

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Suresh Ambati ◽  
Emma C. Ellis ◽  
Jianfeng Lin ◽  
Xiaorong Lin ◽  
Zachary A. Lewis ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Aspergillus Fumigatus ◽  
Effective Dose ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Drugs ◽  
Extracellular Matrices ◽  
Content Type ◽  
Order Of Magnitude ◽  
Life Threatening

ABSTRACT Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus cause life-threatening candidiasis, cryptococcosis, and aspergillosis, resulting in several hundred thousand deaths annually. The patients at the greatest risk of developing these life-threatening invasive fungal infections have weakened immune systems. The vulnerable population is increasing due to rising numbers of immunocompromised individuals as a result of HIV infection or immunosuppressed individuals receiving anticancer therapies and/or stem cell or organ transplants. While patients are treated with antifungals such as amphotericin B, all antifungals have serious limitations due to lack of sufficient fungicidal effect and/or host toxicity. Even with treatment, 1-year survival rates are low. We explored methods of increasing drug effectiveness by designing fungicide-loaded liposomes specifically targeted to fungal cells. Most pathogenic fungi are encased in cell walls and exopolysaccharide matrices rich in mannans. Dectin-2 is a mammalian innate immune membrane receptor that binds as a dimer to mannans and signals fungal infection. We coated amphotericin-loaded liposomes with monomers of Dectin-2’s mannan-binding domain, sDectin-2. sDectin monomers were free to float in the lipid membrane and form dimers that bind mannan substrates. sDectin-2-coated liposomes bound orders of magnitude more efficiently to the extracellular matrices of several developmental stages of C. albicans, C. neoformans, and A. fumigatus than untargeted control liposomes. Dectin-2-coated amphotericin B-loaded liposomes reduced the growth and viability of all three species more than an order of magnitude more efficiently than untargeted control liposomes and dramatically decreased the effective dose. Future efforts focus on examining pan-antifungal targeted liposomal drugs in animal models of fungal diseases. IMPORTANCE Invasive fungal diseases caused by Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus have mortality rates ranging from 10 to 95%. Individual patient costs may exceed $100,000 in the United States. All antifungals in current use have serious limitations due to host toxicity and/or insufficient fungal cell killing that results in recurrent infections. Few new antifungal drugs have been introduced in the last 2 decades. Hence, there is a critical need for improved antifungal therapeutics. By targeting antifungal-loaded liposomes to α-mannans in the extracellular matrices secreted by these fungi, we dramatically reduced the effective dose of drug. Dectin-2-coated liposomes loaded with amphotericin B bound 50- to 150-fold more strongly to C. albicans, C. neoformans, and A. fumigatus than untargeted liposomes and killed these fungi more than an order of magnitude more efficiently. Targeting drug-loaded liposomes specifically to fungal cells has the potential to greatly enhance the efficacy of most antifungal drugs.

scholarly journals In VitroInteraction between Alginate Lyase and Amphotericin B against Aspergillus fumigatus Biofilm Determined by Different Methods

2012 ◽  
Vol 57 (3) ◽  
pp. 1275-1282 ◽  
Author(s):  
Francesca Bugli ◽  
Brunella Posteraro ◽  
Massimiliano Papi ◽  
Riccardo Torelli ◽  
Alessandro Maiorana ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Extracellular Polymeric Substances ◽  
Alginate Lyase ◽  
Antifungal Drugs ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Time Kill

ABSTRACTAspergillus fumigatusbiofilms represent a problematic clinical entity, especially because of their recalcitrance to antifungal drugs, which poses a number of therapeutic implications for invasive aspergillosis, the most difficult-to-treatAspergillus-related disease. While the antibiofilm activities of amphotericin B (AMB) deoxycholate and its lipid formulations (e.g., liposomal AMB [LAMB]) are well documented, the effectiveness of these drugs in combination with nonantifungal agents is poorly understood. In the present study,in vitrointeractions between polyene antifungals (AMB and LAMB) and alginate lyase (AlgL), an enzyme degrading the polysaccharides produced as extracellular polymeric substances (EPSs) within the biofilm matrix, againstA. fumigatusbiofilms were evaluated by using the checkerboard microdilution and the time-kill assays. Furthermore, atomic force microscopy (AFM) was used to image and quantify the effects of AlgL-antifungal combinations on biofilm-growing hyphal cells. On the basis of fractional inhibitory concentration index values, synergy was found between both AMB formulations and AlgL, and this finding was also confirmed by the time-kill test. Finally, AFM analysis showed that whenA. fumigatusbiofilms were treated with AlgL or polyene alone, as well as with their combination, both a reduction of hyphal thicknesses and an increase of adhesive forces were observed compared to the findings for untreated controls, probably owing to the different action by the enzyme or the antifungal compounds. Interestingly, marked physical changes were noticed inA. fumigatusbiofilms exposed to the AlgL-antifungal combinations compared with the physical characteristics detected after exposure to the antifungals alone, indicating that AlgL may enhance the antibiofilm activity of both AMB and LAMB, perhaps by disrupting the hypha-embedding EPSs and thus facilitating the drugs to reach biofilm cells. Taken together, our results suggest that a combination of AlgL and a polyene antifungal may prove to be a new therapeutic strategy for invasive aspergillosis, while reinforcing the EPS as a valuable antibiofilm drug target.

scholarly journals Intrahepatic Administration of Liposomal Amphotericin B (Ambisome) for the Management of a Liver Abscess from Candida albicans in a Preterm Infant

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Cinzia Auriti ◽  
Maria Paola Ronchetti ◽  
Iliana Bersani ◽  
Fabrizio Gennari ◽  
Fiammetta Piersigilli
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Liposomal Amphotericin ◽  
Preterm Neonate ◽  
Neonatal Period ◽  
Newborn Infants ◽  
Liposomal Amphotericin B ◽  
Content Type ◽  
Life Threatening ◽  
Intralesional Administration

ABSTRACT Hepatic fungal abscesses are rare in the neonatal period and often constitute a severe complication of the catheterization of the umbilical vessels. Such life-threatening lesions are observed more frequently in preterm than in other newborn infants and the optimal treatment remains uncertain. We present the case of a preterm neonate, who developed an intrahepatic lesion due to parenteral extravasation, successively contaminated by Candida albicans. Despite the maximal pharmacological therapies, the treatment that led to the definitive resolution of the abscess was the placement of surgical drainage followed by the direct intralesional administration of liposomal amphotericin B (Ambisome), never described in neonates in the literature, which turned out to be a safe and effective approach.

scholarly journals Modulation of Morphogenesis in Candida albicans by Various Small Molecules

2011 ◽  
Vol 10 (8) ◽  
pp. 1004-1012 ◽  
Author(s):  
Julie Shareck ◽  
Pierre Belhumeur
Keyword(s):  
Candida Albicans ◽  
Small Molecules ◽  
Histone Deacetylase Inhibitors ◽  
Therapeutic Potential ◽  
Antifungal Drugs ◽  
Pathogenic Yeast ◽  
Content Type ◽  
Life Threatening ◽  
Experimental Findings ◽  
Cell Cycle Inhibitors

ABSTRACTThe pathogenic yeastCandida albicans, a member of the mucosal microbiota, is responsible for a large spectrum of infections, ranging from benign thrush and vulvovaginitis in both healthy and immunocompromised individuals to severe, life-threatening infections in immunocompromised patients. A striking feature ofC. albicansis its ability to grow as budding yeast and as filamentous forms, including hyphae and pseudohyphae. The yeast-to-hypha transition contributes to the overall virulence ofC. albicansand may even constitute a target for the development of antifungal drugs. Indeed, impairing morphogenesis inC. albicanshas been shown to be a means to treat candidiasis. Additionally, a large number of small molecules such as farnesol, fatty acids, rapamycin, geldanamycin, histone deacetylase inhibitors, and cell cycle inhibitors have been reported to modulate the yeast-to-hypha transition inC. albicans. In this minireview, we take a look at molecules that modulate morphogenesis in this pathogenic yeast. When possible, we address experimental findings regarding their mechanisms of action and their therapeutic potential. We discuss whether or not modulating morphogenesis constitutes a strategy to treatCandidainfections.

scholarly journals Expression Turnover Profiling To Monitor the Antifungal Activities of Amphotericin B, Voriconazole, and Micafungin against Aspergillus fumigatus

2012 ◽  
Vol 56 (5) ◽  
pp. 2770-2772 ◽  
Author(s):  
Yanan Zhao ◽  
Padmaja Paderu ◽  
Steven Park ◽  
Aleksandra Dukhan ◽  
Meredith Senter ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Candidate Genes ◽  
Amphotericin B ◽  
Antifungal Therapy ◽  
Treatment Efficacy ◽  
Antifungal Drugs ◽  
Live Cells ◽  
Content Type ◽  
Kinetics Of ◽  
Potential Biomarkers

ABSTRACTEight highly expressed candidate genes were selected for mRNA profiling to monitor the transcriptome kinetics ofAspergillus fumigatusstrains exposed to antifungal drugs as potential biomarkers of live cells to assess treatment efficacy. Mycelia were treated with fungicidal drugs amphotericin B and voriconazole, as well as the fungistatic drug micafungin. Transcription was monitored at 0, 4, 8, and 24 h posttreatment. The expression turnover profile provides a possible tool to assess antifungal therapy effects.

scholarly journals Synergistic Activity of the Tyrocidines, Antimicrobial Cyclodecapeptides from Bacillus aneurinolyticus, with Amphotericin B and Caspofungin against Candida albicans Biofilms

2014 ◽  
Vol 58 (7) ◽  
pp. 3697-3707 ◽  
Author(s):  
Anscha Mari Troskie ◽  
Marina Rautenbach ◽  
Nicolas Delattin ◽  
Johan Arnold Vosloo ◽  
Margitta Dathe ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Membrane Integrity ◽  
Antifungal Drugs ◽  
Infection Model ◽  
Synergistic Activity ◽  
Significant Activity ◽  
Content Type ◽  
Micromolar Range

ABSTRACTTyrocidines are cationic cyclodecapeptides fromBacillus aneurinolyticusthat are characterized by potent antibacterial and antimalarial activities. In this study, we show that various tyrocidines have significant activity against planktonicCandida albicansin the low-micromolar range. These tyrocidines also preventedC. albicansbiofilm formationin vitro. Studies with the membrane-impermeable dye propidium iodide showed that the tyrocidines disrupt the membrane integrity of matureC. albicansbiofilm cells. This membrane activity correlated with the permeabilization and rapid lysis of model fungal membranes containing phosphatidylcholine and ergosterol (70:30 ratio) induced by the tyrocidines. The tyrocidines exhibited pronounced synergistic biofilm-eradicating activity in combination with two key antifungal drugs, amphotericin B and caspofungin. Using aCaenorhabditis elegansinfection model, we found that tyrocidine A potentiated the activity of caspofungin. Therefore, tyrocidines are promising candidates for further research as antifungal drugs and as agents for combinatorial treatment.

scholarly journals Correlation of Susceptibility of Cryptococcus neoformans to Amphotericin B with Clinical Outcome

2011 ◽  
Vol 55 (12) ◽  
pp. 5624-5630 ◽  
Author(s):  
R. A. Larsen ◽  
M. Bauer ◽  
P. Pitisuttithum ◽  
A. Sanchez ◽  
S. Tansuphaswadikul ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Rank Correlation ◽  
Biological Response ◽  
Quantitative Measure ◽  
Antifungal Drugs ◽  
Susceptibility Test ◽  
Content Type ◽  
Broth Macrodilution

ABSTRACTTesting ofCryptococcus neoformansfor susceptibility to antifungal drugs by standard microtiter methods has not been shown to correlate with clinical outcomes. This report describes a modified quantitative broth macrodilution susceptibility method showing a correlation with both the patient's quantitative biological response in the cerebrospinal fluid (CSF) and the survival of 85 patients treated with amphotericin B (AMB). The Spearman rank correlation between the quantitativein vitromeasure of susceptibility and the quantitative measure of the number of organisms in the patient's CSF was 0.37 (P< 0.01; 95% confidence interval [95% CI], 0.20, 0.60) for the first susceptibility test replicate and 0.46 (P< 0.001; 95% CI, 0.21, 0.62) for the second susceptibility test replicate. The medianin vitroestimated response (defined as the fungal burden after AMB treatment) at 1.5 mg/liter AMB for patients alive at day 14 was 5 CFU (95% CI, 3, 8), compared to 57 CFU (95% CI, 4, 832) for those who died before day 14. These exploratory results suggest that patients whose isolates show a quantitativein vitrosusceptibility response below 10 CFU/ml were more likely to survive beyond day 14.

scholarly journals Trends in Antifungal Drug Susceptibility of Cryptococcus neoformans Isolates Obtained through Population-Based Surveillance in South Africa in 2002-2003 and 2007-2008

2011 ◽  
Vol 55 (6) ◽  
pp. 2606-2611 ◽  
Author(s):  
Nelesh P. Govender ◽  
Jaymati Patel ◽  
Marelize van Wyk ◽  
Tom M. Chiller ◽  
Shawn R. Lockhart ◽  
...  
Keyword(s):  
South Africa ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Drug Susceptibility ◽  
Population Based ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTCryptococcus neoformansis the most common cause of meningitis among adult South Africans with HIV infection/AIDS. Widespread use of fluconazole for treatment of cryptococcal meningitis and other HIV-associated opportunistic fungal infections in South Africa may lead to the emergence of isolates with reduced fluconazole susceptibility. MIC testing using a reference broth microdilution method was used to determine if isolates with reduced susceptibility to fluconazole or amphotericin B had emerged among cases of incident disease. Incident isolates were tested from two surveillance periods (2002-2003 and 2007-2008) when population-based surveillance was conducted in Gauteng Province, South Africa. These isolates were also tested for susceptibility to flucytosine, itraconazole, voriconazole, and posaconazole. Serially collected isolate pairs from cases at several large South African hospitals were also tested for susceptibility to fluconazole. Of the 487 incident isolates tested, only 3 (0.6%) demonstrated a fluconazole MIC of ≥16 μg/ml; all of these isolates were from 2002-2003. All incident isolates were inhibited by very low concentrations of amphotericin B and exhibited very low MICs to voriconazole and posaconazole. Of 67 cases with serially collected isolate pairs, only 1 case was detected where the isolate collected more than 30 days later had a fluconazole MIC value significantly higher than the MIC of the corresponding incident isolate. Although routine antifungal susceptibility testing of incident isolates is not currently recommended in clinical settings, it is still clearly important for public health to periodically monitor for the emergence of resistance.

scholarly journals In VitroActivities of Nine Antifungal Drugs against 81 Phialophora and Cyphellophora Isolates

2012 ◽  
Vol 56 (11) ◽  
pp. 6044-6047 ◽  
Author(s):  
Peiying Feng ◽  
M. Javad Najafzadeh ◽  
Jiufeng Sun ◽  
Sarah Ahmed ◽  
Liyan Xi ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Drugs ◽  
Content Type

ABSTRACTCyphellophora guyanensis(n= 15), otherCyphellophoraspecies (n= 11),Phialophora europaea(n= 43), and otherPhialophoraspecies (n= 12) were testedin vitroagainst nine antifungal drugs. The MIC90s across all of the strains (n= 81) were, in increasing order, as follows: posaconazole, 0.063 μg/ml; itraconazole, 0.5 μg/ml; voriconazole, 1 μg/ml; micafungin, 1 μg/ml; terbinafine, 2 μg/ml; isavuconazole, 4 μg/ml; caspofungin, 4 μg/ml; fluconazole, 8 μg/ml; amphotericin B, 16 μg/ml.

scholarly journals Candida albicans Activation of Human Monocytes Toward M2 Profile is Reversed by Amphotericin B and Fluconazole

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Icely PA ◽  
◽  
Vigezzi C ◽  
Rodriguez E ◽  
Miró MS ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Candida Albicans ◽  
Amphotericin B ◽  
Immune Cells ◽  
Fungal Growth ◽  
Antifungal Drugs ◽  
Arginase Activity ◽  
Intrinsic Activity ◽  
No Production ◽  
Human Monocytes

Phagocytes, including monocytes/macrophages, play an important role in the host defense during Candida albicans infections. In the L-arginine metabolism, the balance between the activation of two enzymes, inducible Nitric Oxide Synthase (iNOS) and arginase, promotes in the macrophages two alternative metabolic states, while M1 profile is related with host protection, M2 favored the fungal growth and evasion. Our aim was to evaluate the effect of Amphotericin B (AMB) and Fluconazole (FLC) on polarization of human monocytes to M2 profile induced by C. albicans. The human monocytic (Mo) cell line U937 was co-cultured with viable yeast of C. albicans, or Lipopolysaccharides (LPS) or Phorbol-12-myristate-13-acetate (PMA). Nitric Oxide (NO), cytokines production and arginase activity were evaluated. The effect of AMB or FLC on these metabolic pathways in immune cells and on fungus intrinsic arginase activity was studied. C. albicans inhibits NO production in human-monocyte and induces strong host arginase activity (p<0.0001). AMB and FLC inhibited C. albicansinduced arginase activity in immune cells (p<0.001), reaching a percentage of inhibition of 90% for AMB and 78% for FLC. Arginase intrinsic activity of the fungus was blocked by nor-NOHA (arginase inhibitor) and AMB (p<0.05). These results show that C. albicans drives human Mo toward M2 profile and that both antifungal drugs evaluated have the ability to revert C. albicans-induced M2 profile. In a relevant manner, it also provides data about additional effect of AMB as inhibitor of C. albicans endogenous arginase activity. Here in we provide new evidence for the effect of these drugs over the immune cells and the yeast.

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