Synergysm of voriconazole or itraconazole with other antifungal agents against species of Fusarium

Disseminated Bisifusarium infection following toxic epidermal necrolysis in a child with B-cell acute lymphoblastic leukemia

Fusarium is a polyphyletic genus of plant pathogens, members of which can cause opportunistic human infections with varying superficial and systemic presentations, including disseminated infections which typically occur in immunocompromised patients and have a poor prognosis. Treatment is challenging due to intrinsic resistance to many antifungal agents, and antifungal susceptibility testing is therefore essential. Early suspicion, isolation of the organism, and prompt initiation of management are crucial to improving survival. We present a case of disseminated Bisifusarium infection following toxic epidermal necrolysis in a child with B-cell acute lymphoblastic leukemia, successfully treated with liposomal amphotericin B, voriconazole, flucytosine, and terbinafine.

Inhibition of Serine Protease, α-Amylase and Growth of Phytopathogenic Fungi by Antimicrobial Peptides from Capsicum chinense Fruits

Plant fungal diseases cause major problems for the global economy. Antimicrobial peptides have aroused great interest in the control of phytopathogens, as they are natural molecules and have a broad spectrum of inhibitory activity. Herein, we have tried to identify and characterize antimicrobial peptides present in fruits of Capsicum chinense and to evaluate their enzymatic and antifungal activities. The retained fraction obtained in the anion exchange chromatography with strong antifungal activity was subjected to molecular exclusion chromatography and obtained four fractions named G1, G2, G3, and G4. The 6.0-kDa protein band of G2 showed similarity with protease inhibitors type II, and it was able to inhibit 100% of trypsin and α-amylase activities. The protein band with approximately 6.5 kDa of G3 showed similarity with sequences of protease inhibitors from genus Capsicum and showed growth inhibition of 48% for Colletotrichum lindemuthianum, 49% for Fusarium lateritium, and 51% for F. solani and F. oxysporum. Additionally, G3 causes morphological changes, membrane permeabilization, and ROS increase in F. oxysporum cells. The 9-kDa protein band of G4 fraction was similar to a nsLTP type 1, and a protein band of 6.5 kDa was similar to a nsLTP type 2. The G4 fraction was able to inhibit 100% of the activities of glycosidases tested and showed growth inhibition of 35 and 50% of F. oxysporum and C. lindemuthianum, respectively. C. chinense fruits have peptides with antifungal activity and enzyme inhibition with biotechnological potential.

In vitro antifungal combination of terbinafine with itraconazole against isolates of Trichophyton spp

Terbinafine is used as first-line therapy for dermatophytosis, but the incidence of terbinafine-resistance is increasing. Combination of terbinafine with itraconazole was tested by checkerboard based on the EUCAST methodology for antifungal susceptibility testing against 9 terbinafine-susceptible and 7 terbinafine-resistant clinical isolates of Trichophyton spp. from India. Synergistic interactions were observed for 4/9 of the susceptible isolates with fractional inhibitory concentration index (FICI) values of 0.3125 to 0.5 and for 4/7 of the resistant isolates with FICI values of 0.032 to 0.3125.

In Vitro Combination Effect of Topical and Oral Anti-Onychomycosis Drugs on Trichophyton rubrum and Trichophyton interdigitale

To evaluate the combination effects of anti-onychomycosis drugs, the minimum inhibitory concentrations of topical (efinaconazole, luliconazole, and tavaborole) and oral (itraconazole and terbinafine) drugs for Trichophyton rubrum and Trichophyton interdigitale (8 each, with a total of 16 strains) were determined using the microdilution checkerboard technique based on the Clinical and Laboratory Standard Institute guidelines. No antagonism was observed between the topical and oral drugs against all the tested strains. Efinaconazole with terbinafine exerted a synergistic effect on 43.8% of the strains tested (7/16 strains) and efinaconazole with itraconazole on 12.5% (2/16 strains). Conversely, luliconazole showed no synergistic effect with terbinafine but was synergistically effective with itraconazole against 31.3% of the strains (5/16 strains). Tavaborole showed no synergistic effect with terbinafine and was synergistically effective with itraconazole against 18.8% of the strains (3/16 strains). The results suggest that a combination of topical and oral drugs could be a potential clinical option for onychomycosis treatment, and overall, the efinaconazole and oral drug combination would be the most advantageous among the tested combinations.

Disseminated fusariosis in immunocompromised children: a case series and review of literature

In the era of antifungal prophylaxis for cancer patients, Fusarium genus has become the second leading cause of invasive fungal infections and mortality in this group of patients. The intrinsic resistance to antifungal agents and the patient's risk factors are the most important variables for prognosis and survival. Currently, the use of monotherapy in comparison to combined antifungal treatment information is scarce. In this report, we present a series of three cases of children with acute lymphoblastic leukemia and disseminated fusariosis categorized according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG). Furthermore, we present a current literature review focused on treatment using monotherapy or combined antifungal treatment.

Human fusariosis: An emerging infection that is difficult to treat

Fusarium spp. has been associated with a broad spectrum of emerging infections collectively termed fusariosis. This review includes articles published between 2005 and 2018 that describe the characteristics, clinical management, incidence, and emergence of these fungal infections. Fusarium solani and F. oxysporum are globally distributed and represent the most common complexes. Few therapeutic options exist due to intrinsic resistance, especially for the treatment of invasive fusariosis. Therefore, the use of drug combinations could be an important alternative for systemic antifungal resistance. Increase in the number of case reports on invasive fusariosis between 2005 and 2018 is evidence of the emergence of this fungal infection.

Potent Activities of Luliconazole, Lanoconazole, and Eight Comparators against Molecularly Characterized Fusarium Species

A collection of clinical (n = 47) and environmental (n = 79) Fusarium isolates were tested against 10 antifungal drugs, including 2 novel imidazoles. Luliconazole and lanoconazole demonstrated very low geometric mean MIC values of 0.005 and 0.013 μg/ml, respectively, compared with 0.51 μg/ml for micafungin, 0.85 μg/ml for efinaconazole, 1.12 μg/ml for natamycin, 1.18 μg/ml for anidulafungin, 1.31 μg/ml for voriconazole, 1.35 μg/ml for caspofungin, 1.9 μg/ml for amphotericin B, and 4.08 μg/ml for itraconazole. Results show that these drugs are potential candidates for (topical) treatment of skin and nail infections due to Fusarium species.

Antifungals discovery: an insight into new strategies to combat antifungal resistance

Undeniably, new antifungal treatments are necessary against pathogenic fungi. Fungal infections have significantly increased in recent decades, being highlighted as important causes of morbidity and mortality, particularly in immunocompromised patients. Five main antifungal classes are used: (i) azoles, (ii) echinocandins, (iii) polyenes, (iv) allylamines and (v) pyrimidine analogues. Moreover, the treatment of mycoses has several limitations, such as undesirable side effects, narrow activity spectrum, a small number of targets and fungal resistance, which are still of major concern in clinical practice. The discovery of new antifungals is mostly achieved by the screening of natural or synthetic/semisynthetic chemical compounds. The most recent discoveries in drug resistance mechanism and their avoidance were explored in a review, focusing on different antifungal targets, as well as new agents or strategies, such as combination therapy, that could improve antifungal therapy.

SIGNIFICANCE AND IMPACT OF THE STUDY

The failure to respond to antifungal therapy is complex and is associated with microbiological resistance and increased expression of virulence in fungal pathogens. Thus, this review offers an overview of current challenges in the treatment of fungal infections associated with increased antifungal drug resistance and the formation of biofilms in these opportunistic pathogens. Furthermore, the most recent and potential strategies to combat fungal pathogens are explored here, focusing on new agents as well as innovative approaches, such as combination therapy between antifungal drugs or with natural compounds.

Current antifungal treatment of fusariosis

Fungi of the genus Fusarium are well known as major plant pathogens and soil inhabitants, but also cause a broad spectrum of human infections. Fusariosis is the second most common mould infection after aspergillosis, and keratitis is the most encountered implantation infection in immunocompetent individuals. Natamycin is active against Fusarium species both in vitro and in vivo, and is used along with voriconazole as the mainstay of treatment for Fusarium keratitis. Onychomycosis is treated with terbinafine, voriconazole and sometimes itraconazole. Cure is possible despite high in vitro minimum inhibitory concentrations (MICs). Recently, disseminated infections have increased dramatically, mainly affecting severely immunocompromised patients. The remarkable intrinsic resistance of Fusarium species to most antifungal agents results in high mortality rates in this patient population. Recovery of neutropenia is essential for patient survival and treatment should include voriconazole or amphotericin B as first-line and posaconazole as salvage therapy.

In vitro combinations of natamycin with voriconazole, itraconazole and micafungin against clinical Fusarium strains causing keratitis

OBJECTIVES

Fusarium species cause a broad spectrum of infections, from superficial to disseminated disease. Because Fusarium species are intrinsically resistant to most antifungal drugs, new approaches are needed. The aim of the present study was to evaluate the in vitro combination of natamycin with currently used antifungal drugs.

METHODS

The in vitro interactions of combinations between natamycin and voriconazole, itraconazole and micafungin applied to 20 clinical Fusarium strains (members of Fusarium falciforme, Fusarium napiforme, Fusarium petroliphilum, Fusarium proliferatum, Fusarium pseudensiforme and Fusarium sacchari) were evaluated using a chequerboard microdilution method. The MICs of all drugs alone and in combination were determined visually after 48 h and interactions were assessed using fractional inhibitory concentration index (FICI) analysis.

RESULTS

MICs of voriconazole and natamycin alone were 4 to >16 and 4-8 mg/L, respectively. Values were reduced 3.5-10-fold to 0.02-0.5 mg/L and 0.5-5-fold to 0.13-2 mg/L in combination, for the currently used antifungals and natamycin, respectively, demonstrating additive to synergistic interactions. The combinations natamycin/voriconazole, natamycin/itraconazole and natamycin/micafungin were synergistic (FICI ≤0.5) for 70%, 15% and 5% of the strains, respectively. No antagonism was found.

CONCLUSIONS

The combination of natamycin with voriconazole was strongly synergistic at clinically achievable serum concentrations.

Invasive Fusariosis in the Voriconazole Era: Single-Center 13-Year Experience

Invasive fusariosis is an aggressive fungal disease among immunocompromised patients. Mortality remains high in the voriconazole era. Combination therapy should be studied systematically for fusariosis.

Background. Invasive fusariosis remains an aggressive, albeit infrequent infection in immunocompromised patients.

Methods. We identified all cases of invasive fusariosis between January 2002 and December 2014. We recorded patient characteristics including clinical presentation, treatment, and outcomes at 6 and 12 weeks after diagnosis, as well as species identification and antifungal drug susceptibilities.

Results. Fifteen patients were diagnosed with proven (12, 80%) or probable (3, 20%) fusariosis. Median age was 60 years (range, 26–78), and 10 patients were male. Underlying conditions included hematological malignancies (13, 87%), juvenile idiopathic arthritis (1, 7%), and third-degree burns (1, 7%). Five patients underwent hematopoietic stem-cell transplantation before diagnosis. Six patients (40%) received systemic glucocorticoids, and 11 patients (73%) had prolonged neutropenia at the time of diagnosis. Clinical presentations included the following: skin/soft tissue infection (8, 53%), febrile neutropenia (4, 27%), respiratory tract infection (2, 13%), and septic arthritis (1, 7%). Twelve patients were treated with voriconazole: 6 (40%) with voriconazole alone, 4 (27%) with voriconazole and terbinafine, and 2 (13%) with voriconazole, terbinafine, and amphotericin. One patient (7%) was treated with terbinafine alone, and another with micafungin alone. Four patients underwent surgical debridement (4, 27%). Susceptibility testing was performed on 9 isolates; 8 demonstrated voriconazole minimum inhibitory concentrations ≥4 µg/mL. The cumulative probability of survival was 66.7% and 53.3% at 6 and 12 weeks after diagnosis.

Conclusions. Mortality associated with invasive fusariosis remains high. Cumulative mortality at our center was lower than previous reports despite elevated voriconazole minimum inhibitory concentrations. Combination therapy should be studied systematically for fusariosis.

Invasive Fusariosis: A Single Pediatric Center 15-Year Experience

Invasive fungal infection (IFI) is an important cause of mortality in immunocompromised children, particularly after hematopoietic stem cell transplantation. We describe 5 cases of Fusarium IFI in immunocompromised children seen at our institution over a 15-year period. A summary of all published pediatric cases of invasive Fusarium infection is presented. A focus on antifungal management challenges in these patients will be discussed.

Disseminated fusariosis and hematologic malignancies, a still devastating association. Report of three new cases

BACKGROUND

Fungi of the genus Fusarium are primarily plant pathogens and saprobes that produce disseminated infections in immunologically deficient humans. After aspergillosis, disseminated fusariosis is the second most common cause of invasive infection by filamentous fungi in patients with hematologic malignancies or those undergoing transplants of hematopoietic progenitors.

AIMS

Disseminated fusariosis (DF) is considered an extremely rare infection and has reached a stable incidence rate, but its high mortality rate and the lack of an optimal management protocol have raised increasing interest in this mycosis.

METHODS

We present three cases of DF produced by Fusarium oxysporum species complex, Fusarium solani species complex and the highly unusual Fusarium dimerum in patients with advanced hematological malignancies diagnosed in our hospital between 2007 and 2011. The species level identification of the Fusarium isolates was established by sequencing their TEF1 gene.

RESULTS

The isolates showed low susceptibility to most of the antifungal agents analyzed, except that observed for F. dimerum to amphotericin B (AmB) and terbinafine, and F. oxysporum species complex to AmB. Interestingly, the strain of F. solani species complex exhibited high MIC values for AmB and voriconazole, notwithstanding these drugs were used for treatment with good results. Other relevant aspects to be considered in the treatment of DF are surgically cleaning foci of infection, withdrawing presumably contaminated catheters and recovery from neutropenia.

CONCLUSIONS

The prevention of infection in colonized patients, the maintenance of a high level of diagnostic suspicion for early diagnosis, and the combined, vigorous and prolonged use of L-AmB and voriconazole are essential to decrease the mortality rate of this devastating infection.

Large-scale exploration and analysis of drug combinations

MOTIVATION

Drug combinations are a promising strategy for combating complex diseases by improving the efficacy and reducing corresponding side effects. Currently, a widely studied problem in pharmacology is to predict effective drug combinations, either through empirically screening in clinic or pure experimental trials. However, the large-scale prediction of drug combination by a systems method is rarely considered.

RESULTS

We report a systems pharmacology framework to predict drug combinations (PreDCs) on a computational model, termed probability ensemble approach (PEA), for analysis of both the efficacy and adverse effects of drug combinations. First, a Bayesian network integrating with a similarity algorithm is developed to model the combinations from drug molecular and pharmacological phenotypes, and the predictions are then assessed with both clinical efficacy and adverse effects. It is illustrated that PEA can predict the combination efficacy of drugs spanning different therapeutic classes with high specificity and sensitivity (AUC = 0.90), which was further validated by independent data or new experimental assays. PEA also evaluates the adverse effects (AUC = 0.95) quantitatively and detects the therapeutic indications for drug combinations. Finally, the PreDC database includes 1571 known and 3269 predicted optimal combinations as well as their potential side effects and therapeutic indications.

AVAILABILITY AND IMPLEMENTATION

The PreDC database is available at http://sm.nwsuaf.edu.cn/lsp/predc.php.