Comparison of Bloodstream and Vaginal Candida albicans isolates: Susceptibility to Antifungal Drugs and Pathogenicity in an Experimental Infection

Author(s):  
E. Segal
2019 ◽  
Vol 15 (6) ◽  
pp. 648-658 ◽  
Author(s):  
Manzoor Ahmad Malik ◽  
Shabir Ahmad Lone ◽  
Parveez Gull ◽  
Ovas Ahmad Dar ◽  
Mohmmad Younus Wani ◽  
...  

Background: The increasing incidence of fungal infections, especially caused by Candida albicans, and their increasing drug resistance has drastically increased in recent years. Therefore, not only new drugs but also alternative treatment strategies are promptly required. Methods: We previously reported on the synergistic interaction of some azole and non-azole compounds with fluconazole for combination antifungal therapy. In this study, we synthesized some non-azole Schiff-base derivatives and evaluated their antifungal activity profile alone and in combination with the most commonly used antifungal drugs- fluconazole (FLC) and amphotericin B (AmB) against four drug susceptible, three FLC resistant and three AmB resistant clinically isolated Candida albicans strains. To further analyze the mechanism of antifungal action of these compounds, we quantified total sterol contents in FLC-susceptible and resistant C. albicans isolates. Results: A pyrimidine ring-containing derivative SB5 showed the most potent antifungal activity against all the tested strains. After combining these compounds with FLC and AmB, 76% combinations were either synergistic or additive while as the rest of the combinations were indifferent. Interestingly, none of the combinations was antagonistic, either with FLC or AmB. Results interpreted from fractional inhibitory concentration index (FICI) and isobolograms revealed 4-10-fold reduction in MIC values for synergistic combinations. These compounds also inhibit ergosterol biosynthesis in a concentration-dependent manner, supported by the results from docking studies. Conclusion: The results of the studies conducted advocate the potential of these compounds as new antifungal drugs. However, further studies are required to understand the other mechanisms and in vivo efficacy and toxicity of these compounds.


Author(s):  
Gunderao Hanumantrao Kathwate ◽  
Ravikumar Bapurao Shinde ◽  
S. Mohan Karuppayil

Author(s):  
Daiki Sakai ◽  
Wataru Matsumiya ◽  
Sentaro Kusuhara ◽  
Makoto Nakamura

Abstract Purpose To evaluate the factors associated with the development of ocular candidiasis (OC) and ocular prognosis with echinocandin therapy for candidemia. Methods The medical records of 56 consecutive patients with a positive blood culture for Candida species between November 2016 and October 2019 were retrospectively reviewed. Information on patient characteristics, isolated Candida species, treatment details for candidemia, and ocular findings were extracted to identify factors associated with OC development. Results The leading pathogen of candidemia was Candida albicans (C.albicans) (41.1%). Of 56 patients, 18 (32.1%) were diagnosed with chorioretinitis, categorized as either probable (8 patients) or possible OC (10 patients). There was no case of endophthalmitis with vitritis. The incidence of probable OC was not significantly different between the groups treated with echinocandins and other antifungal drugs (15.2% vs. 11.1%, p = 1.00). In all probable OC cases, systemic antifungal therapy was switched from echinocandins to azoles, and no case progressed to endophthalmitis. A multivariate logistic analysis revealed that female sex (adjusted odds ratio [aOR], 8.93; 95% confidence interval [CI], 1.09–72.9) and C. albicans (aOR, 23.6; 95% CI, 1.8–281) were independent factors associated with the development of probable OC. Conclusion One-seventh of patients with candidemia developed probable OC. Given the evidence of female and C. albicans as the factors associated with OC development, careful ophthalmologic management is required with these factors, especially in candidemia. Although echinocandins had no correlation with OC development and did not lead to the deterioration of ocular prognosis, further investigation is required.


mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Suresh Ambati ◽  
Emma C. Ellis ◽  
Jianfeng Lin ◽  
Xiaorong Lin ◽  
Zachary A. Lewis ◽  
...  

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.


2004 ◽  
Vol 48 (12) ◽  
pp. 4505-4512 ◽  
Author(s):  
Chia-Geun Chen ◽  
Yun-Liang Yang ◽  
Hsin-I Shih ◽  
Chia-Li Su ◽  
Hsiu-Jung Lo

ABSTRACT Overexpression of CDR1, an efflux pump, is one of the major mechanisms contributing to drug resistance in Candida albicans. CDR1 p-lacZ was constructed and transformed into a Saccharomyces cerevisiae strain so that the lacZ gene could be used as the reporter to monitor the activity of the CDR1 promoter. Overexpression of CaNDT80, the C. albicans homolog of S. cerevisiae NDT80, increases the β-galactosidase activity of the CDR1 p-lacZ construct in S. cerevisiae. Furthermore, mutations in CaNDT80 abolish the induction of CDR1 expression by antifungal agents in C. albicans. Consistently, the Candt80/Candt80 mutant is also more susceptible to antifungal drugs than the wild-type strain. Thus, the gene for CaNdt80 may be the first gene among the regulatory factors involved in drug resistance in C. albicans whose function has been identified.


2021 ◽  
Author(s):  
Mahdi Hosseini Bafghi ◽  
Razieh Nazari ◽  
Majid Darroudi ◽  
Mohsen Zargar ◽  
Hossein Zarrinfar

Abstract Biosynthesis of nanoparticles can stand as a replacement for the available chemical and physical methods by offering new procedures as green syntheses that have proved to be simple, biocompatible, safe, and cost-effective. Considering how nanoparticles with a size of 1 to 100 nanometers contain unique physical and chemical properties, recent reports are indicative of observing the antifungal qualities of selenium nanoparticles (Se-NPs). Recently, the observance of antifungal resistance towards different species of these fungi is often reported. Therefore, due to the antifungal effects of biological nanoparticles, this study aimed to investigate the exertion of these nanoparticles and evaluate their effects on the growth of fungal pathogens. Se-NPs were biosynthesized by the application of wet reduction method, which included specific concentrations of Aspergillus flavus and Candida albicans. The presence of nanoparticles was confirmed by methods such as UV-Vis spectroscopy, FT-IR analysis, and FESEM electron microscope that involved FESEM and EDAX diagram. The fungal strains were cultured in sabouraud dextrose agar medium to perform the sensitivity test based on the minimum inhibitory concentration (MIC) method in duplicate. The utilization of Se-NPs at concentrations of 1 µg/ ml and below resulted in zero growth of fungal agents. However, their growth was inhibited by antifungal drugs at concentrations of 2 µg/ ml and higher. Based on the obtained results, biological nanoparticles produced by fungal agents at different concentrations exhibited favorable inhibitory effects on the growth of fungal strains.


Author(s):  
ASHWINI KHANDERAO JADHAV ◽  
PATHAN KAMRAN KHAN ◽  
SANKUNNY MOHAN KARUPPAYIL

Lanosterol 14 α-demethylase (CYP51) is a key protein involved in ergosterol biosynthesis of Candida albicans and a crucial target for ergosterol synthesis inhibition. However, in the last two decades drug resistance is reported under clinical situations to most of the prescribed antifungal drugs like azole group of drugs. In this study, molecular docking of sixty plant molecules with Lanosterol 14 α-demethylase protein has been done. The homology modeling tool PHYRE2 was used to predict the structure of Lanosterol 14 α-demethylase. Predicted structure was used for docking studies with sixty plant molecules by using Autodock 1.5.6 cr2™. Among the sixty plant molecules, forty-seven were found to form hydrogen bond and the rest of the plant molecules did not form a hydrogen bond with Lanosterol 14 α-demethylase. Docking study of a library of sixty molecules revealed that 48 plant molecules showed an excellent and good binding affinity with predicted protein model Lanosterol 14 α-demethylase of Candida albicans. The binding residue comparison of docked molecules with that of Ketoconazole revealed, fourteen molecules have similar binding residue. These fourteen molecules may have a similar mode of action as that of Ketoconazole. These molecules should be screened and used to discover new antifungal therapeutic drugs.


Author(s):  
Icely PA ◽  
◽  
Vigezzi C ◽  
Rodriguez E ◽  
Miró MS ◽  
...  

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.


mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Eric H. Jung ◽  
David J. Meyers ◽  
Jürgen Bosch ◽  
Arturo Casadevall

ABSTRACTSimilarities in fungal and animal cells make antifungal discovery efforts more difficult than those for other classes of antimicrobial drugs. Currently, there are only three major classes of antifungal drugs used for the treatment of systemic fungal diseases: polyenes, azoles, and echinocandins. Even in situations where the offending fungal organism is susceptible to the available drugs, treatment courses can be lengthy and unsatisfactory, since eradication of infection is often very difficult, especially in individuals with impaired immunity. Consequently, there is a need for new and more effective antifungal drugs. We have identified compounds with significant antifungal activity in the Malaria Box (Medicines for Malaria Ventures, Geneva, Switzerland) that have higher efficacy than some of the currently used antifungal drugs. Our best candidate, MMV665943 (IUPAC name 4-[6-[[2-(4-aminophenyl)-3H-benzimidazol-5-yl]methyl]-1H-benzimidazol-2-yl]aniline), here referred to as DM262, showed 16- to 32-fold-higher activity than fluconazole againstCryptococcus neoformans. There was also significant antifungal activity in other fungal species with known antifungal resistance, such asLomentospora prolificansandCryptococcus gattii. Antifungal activity was also observed against a common fungus,Candida albicans. These results are important because they offer a potentially new class of antifungal drugs and the repurposing of currently available therapeutics.IMPORTANCEMuch like the recent increase in drug-resistant bacteria, there is a rise in antifungal-resistant strains of pathogenic fungi. There is a need for novel and more potent antifungal therapeutics. Consequently, we investigated a mixed library of drug-like and probe-like compounds with activity inPlasmodiumspp. for activity against two common fungal pathogens,Cryptococcus neoformansandCandida albicans, along with two less common pathogenic species,Lomentospora prolificansandCryptococcus gattii. We uncover a previously uncharacterized drug with higher broad-spectrum antifungal activity than some current treatments. Our findings may eventually lead to a compound added to the arsenal of antifungal therapeutics.


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