scholarly journals Drug Resistance and Novel Therapeutic Approaches in Invasive Candidiasis

Author(s):  
Sarah E. Murphy ◽  
Tihana Bicanic

Candida species are the leading cause of invasive fungal infections worldwide and are associated with acute mortality rates of ~50%. Mortality rates are further augmented in the context of host immunosuppression and infection with drug-resistant Candida species. In this review, we outline antifungal drugs already in clinical use for invasive candidiasis and candidaemia, their targets and mechanisms of resistance in clinically relevant Candida species, encompassing not only classical resistance, but also heteroresistance and tolerance. We describe novel antifungal agents and targets in pre-clinical and clinical development, including their spectrum of activity, antifungal target, clinical trial data and potential in treatment of drug-resistant Candida. Lastly, we discuss the use of combination therapy between conventional and repurposed agents as a potential strategy to combat the threat of emerging resistance in Candida.

Author(s):  
Qian Zhang ◽  
Fangyan Liu ◽  
Meng Zeng ◽  
Caiyan Xin ◽  
Jinping Zhang ◽  
...  

The morbidity and mortality caused by invasive fungal infections is increasing across the globe due to developments in transplant surgery, the use of immunosuppressive agents, and the emergence of drug-resistant fungal strains, which has led to a challenge in terms of treatment due to the limitations of three classes of drugs. Hence, it is imperative to establish effective strategies to identify and design new antifungal drugs. Drug repurposing is an effective way of expanding the application of existing drugs. In the last years, various existing drugs have been shown to be useful in the prevention and treatment of the invasive fungi. In this review, we summarize the currently used antifungal agents. In addition, the most up to date information on the effectiveness of existing drugs with antifungal activity is discussed. Moreover, the antifungal mechanisms of existing drugs are highlighted. These data will provide valuable knowledge to stimulate further investigation and clinical application in this field.


Author(s):  
Hannah Monalis ◽  
R. Sujith ◽  
K. V. Leela ◽  
V. Balamurali

Candida spp. are emerging pathogens of hospital-acquired infections that causes invasive candidiasis, leading to human mortality and morbidity. Evolution of resistance to different groups of antifungal drugs is a major concern nowadays. Resistance mechanism in some of the antifungal drugs are formation of biofilms, alterations in drug target and lowered intracellular drug levels caused by efflux pumps. Introduction of novel strategies are necessitous to eliminate the phenomenon of drug resistance.  Drug repurposing is a promising therapeutic strategy that can improve the efficacy of antifungal therapy for invasive candidiasis. Antibiotics and antifungal drugs were combined against resistant Candida spp. and the in vitro antifungal synergy were analyzed by disk diffusion methods, checkerboard microbroth dilution method and time-kill curves. Synergistic effects were seen against drug-resistant strains, but drug-susceptible strains show indifferent effects in experimental studies. Profiting from the synergistic effects of combination therapy, alternative therapeutic approaches for drug resistance could be designed. This review will discuss different antifungal drugs and their mechanism, drug-resistance mechanisms and some of the antibiotic and antifungal combinations that provide novel insights in treating invasive fungal infections.


2019 ◽  
Vol 16 (5) ◽  
pp. 478-491 ◽  
Author(s):  
Faizan Abul Qais ◽  
Mohd Sajjad Ahmad Khan ◽  
Iqbal Ahmad ◽  
Abdullah Safar Althubiani

Aims: The aim of this review is to survey the recent progress made in developing the nanoparticles as antifungal agents especially the nano-based formulations being exploited for the management of Candida infections. Discussion: In the last few decades, there has been many-fold increase in fungal infections including candidiasis due to the increased number of immunocompromised patients worldwide. The efficacy of available antifungal drugs is limited due to its associated toxicity and drug resistance in clinical strains. The recent advancements in nanobiotechnology have opened a new hope for the development of novel formulations with enhanced therapeutic efficacy, improved drug delivery and low toxicity. Conclusion: Metal nanoparticles have shown to possess promising in vitro antifungal activities and could be effectively used for enhanced and targeted delivery of conventionally used drugs. The synergistic interaction between nanoparticles and various antifungal agents have also been reported with enhanced antifungal activity.


Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 655
Author(s):  
Anna Herman ◽  
Andrzej Przemysław Herman

Clinical isolates of Candida yeast are the most common cause of opportunistic fungal infections resistant to certain antifungal drugs. Therefore, it is necessary to detect more effective antifungal agents that would be successful in overcoming such infections. Among them are some herbal products and their active constituents.The purpose of this review is to summarize the current state of knowledge onherbal products and their active constituents havingantifungal activity against drug-resistant Candida sp. used alone and in combination with antifungal drugs.The possible mechanisms of their action on drug-resistant Candida sp. including (1) inhibition of budding yeast transformation into hyphae; (2) inhibition of biofilm formation; (3) inhibition of cell wall or cytoplasmic membrane biosynthesis; (4) ROS production; and (5) over-expression of membrane transporters will be also described.


2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Cristina Lazzarini ◽  
Krupanandan Haranahalli ◽  
Robert Rieger ◽  
Hari Krishna Ananthula ◽  
Pankaj B. Desai ◽  
...  

ABSTRACTThe incidence of invasive fungal infections has risen dramatically in recent decades. Current antifungal drugs are either toxic, likely to interact with other drugs, have a narrow spectrum of activity, or induce fungal resistance. Hence, there is a great need for new antifungals, possibly with novel mechanisms of action. Previously our group reported an acylhydrazone called BHBM that targeted the sphingolipid pathway and showed strong antifungal activity against several fungi. In this study, we screened 19 derivatives of BHBM. Three out of 19 derivatives were highly active againstCryptococcus neoformansin vitroand had low toxicity in mammalian cells. In particular, one of them, called D13, had a high selectivity index and showed better activity in an animal model of cryptococcosis, candidiasis, and pulmonary aspergillosis. D13 also displayed suitable pharmacokinetic properties and was able to pass through the blood-brain barrier. These results suggest that acylhydrazones are promising molecules for the research and development of new antifungal agents.


2018 ◽  
Author(s):  
Brett A Melnikoff ◽  
René P Myers

Fungal infections remain an important cause of morbidity and mortality in surgical settings, with critically ill patients, transplant recipients, and sick neonates all especially vulnerable. Fungal infections remain an important cause of morbidity and mortality in surgical settings, with critically ill patients, transplant recipients, and sick neonates all especially vulnerable. Despite the development of a number of new and useful antifungal agents in the past decade and the noteworthy improvements in therapeutic approaches to fungal infections, physicians’ ability to diagnose these infections in a timely fashion remains limited, and patient outcomes remain poor. Antifungal prophylaxis has emerged as a potential means of reducing the occurrence of serious fungal infections. In patient populations estimated to be at high risk for acquiring a fungal infection, antifungal prophylaxis has reduced infection rates by about 50%; however, it has not been shown to significantly improve mortality. This review discusses both established and newly approved systemic antifungal agents. Tables list characteristics of currently available antifungals and antifungal chemotherapy. This review contains 2 tables and 32 references Key words: antifungal chemotherapy, antifungal prophylaxis, antifungals, Candida prophylaxis, systemic antifungal medications


Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 445 ◽  
Author(s):  
Gina Wall ◽  
Jose L. Lopez-Ribot

Fungal infections represent an increasing threat to a growing number of immune- and medically compromised patients. Fungi are eukaryotic organisms and, as such, there is a limited number of selective targets that can be exploited for antifungal drug development. This has also resulted in a very restricted number of antifungal drugs that are clinically available for the treatment of invasive fungal infections at the present time—polyenes, azoles, echinocandins, and flucytosine. Moreover, the utility of available antifungals is limited by toxicity, drug interactions and the emergence of resistance, which contribute to high morbidity and mortality rates. This review will present a brief summary on the landscape of current antifungals and those at different stages of clinical development. We will also briefly touch upon potential new targets and opportunities for novel antifungal strategies to combat the threat of fungal infections.


2007 ◽  
Vol 28 (4) ◽  
pp. 174 ◽  
Author(s):  
David Ellis ◽  
Tania Sorrell ◽  
Sharon Chen

The last two to three decades have seen a major increase in invasive fungal infections (IFIs), a small, but increasing proportion of which are caused by pathogens with partial or complete resistance to antifungal drugs. The increase in IFIs has largely been associated with the increase in immunocompromised and critically ill patients. Opportunistic infections with relatively drug-resistant environmental fungi account for much of the resistance. In addition, amongst the only fungal species to colonise humans, Candida, two species that are resistant (C. krusei) or relatively resistant (C. glabrata) to fluconazole have emerged. In part this is explained by the selection pressure exerted by widespread use of fluconazole. Together with the introduction of new antifungal drugs with selective and/or variable antifungal activity, these changes have stimulated interest in understanding mechanisms and origins of resistance, the identification of resistance in the laboratory and its relationship to clinical outcomes, and in surveillance of clinical isolates and populations at risk of IFIs.


Author(s):  
Lisa Kirchhoff ◽  
Silke Dittmer ◽  
Ann-Kathrin Weisner ◽  
Jan Buer ◽  
Peter-Michael Rath ◽  
...  

Abstract Objectives Patients with immunodeficiency or cystic fibrosis frequently suffer from respiratory fungal infections. In particular, biofilm-associated fungi cause refractory infection manifestations, linked to increased resistance to anti-infective agents. One emerging filamentous fungus is Lomentospora prolificans. Here, the biofilm-formation capabilities of L. prolificans isolates were investigated and the susceptibility of biofilms to various antifungal agents was analysed. Methods Biofilm formation of L. prolificans (n = 11) was estimated by crystal violet stain and antibiofilm activity was additionally determined via detection of metabolically active biofilm using an XTT assay. Amphotericin B, micafungin, voriconazole and olorofim were compared with regard to their antibiofilm effects when added prior to adhesion, after adhesion and on mature and preformed fungal biofilms. Imaging via confocal laser scanning microscopy was carried out to demonstrate the effect of drug treatment on the fungal biofilm. Results Antibiofilm activities of the tested antifungal agents were shown to be most effective on adherent cells whilst mature biofilm was the most resistant. The most promising antibiofilm effects were detected with voriconazole and olorofim. Olorofim showed an average minimum biofilm eradication concentration (MBEC) of 0.06 mg/L, when added prior to and after adhesion. The MBECs of voriconazole were ≤4 mg/L. On mature biofilm the MBECs of olorofim and voriconazole were higher than the previously determined MICs against planktonic cultures. In contrast, amphotericin B and especially micafungin did not exhibit sufficient antibiofilm activity against L. prolificans. Conclusions To our knowledge, this is the first study demonstrating the antibiofilm potential of olorofim against the human pathogenic fungus L. prolificans.


2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Juliana Alves Parente-Rocha ◽  
Alexandre Melo Bailão ◽  
André Correa Amaral ◽  
Carlos Pelleschi Taborda ◽  
Juliano Domiraci Paccez ◽  
...  

Diseases caused by fungi can occur in healthy people, but immunocompromised patients are the major risk group for invasive fungal infections. Cases of fungal resistance and the difficulty of treatment make fungal infections a public health problem. This review explores mechanisms used by fungi to promote fungal resistance, such as the mutation or overexpression of drug targets, efflux and degradation systems, and pleiotropic drug responses. Alternative novel drug targets have been investigated; these include metabolic routes used by fungi during infection, such as trehalose and amino acid metabolism and mitochondrial proteins. An overview of new antifungal agents, including nanostructured antifungals, as well as of repositioning approaches is discussed. Studies focusing on the development of vaccines against antifungal diseases have increased in recent years, as these strategies can be applied in combination with antifungal therapy to prevent posttreatment sequelae. Studies focused on the development of a pan-fungal vaccine and antifungal drugs can improve the treatment of immunocompromised patients and reduce treatment costs.


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