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1.
Internalization of a sunflower mannose-binding lectin into phytopathogenic fungal cells induces cytotoxicity.
Del Rio, M, de la Canal, L, Pinedo, M, Regente, M
Journal of plant physiology. 2018;:22-31
Abstract
Lectins are carbohydrate-affinity proteins with the ability to recognize and reversibly bind specific glycoconjugates. We have previously isolated a bioactive sunflower mannose-binding lectin belonging to the jacalin-related family called Helja. Despite of the significant number of plant lectins described in the literature, only a small group exhibits antifungal activity and the mechanism by which they kill fungi is still not understood. The aim of this work was to explore Helja activity on plant pathogenic fungi, and provide insights into its mechanism of action. Through cellular and biochemical experimental approaches, here we show that Helja exerts an antifungal effect on Sclerotinia sclerotiorum, a sunflower pathogen. The lectin interacts with the fungal spore surface, permeabilizes its plasma membrane, can be internalized into the cell and induces oxidative stress, finally leading to the cell death. On the other hand, Helja is inactive towards Fusarium solani, a non-pathogen of sunflower, showing the selective action of the lectin. The mechanistic basis for the antifungal activity of an extracellular jacalin lectin is presented, suggesting its initial interaction with fungal cell wall carbohydrates and further internalization. The implication of our findings for plant defense is discussed.
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2.
Oral Cryotherapy: Prevention of Oral Mucositis and Pain Among Patients With Colorectal Cancer Undergoing Chemotherapy.
Idayu Mat Nawi, R, Lei Chui, P, Wan Ishak, WZ, Hsien Chan, CM
Clinical journal of oncology nursing. 2018;(5):555-560
Abstract
BACKGROUND Evidence remains mixed on the benefits of oral cryotherapy in the prevention of oral mucositis and pain associated with fluorouracil-based chemotherapy. OBJECTIVES The intent of this article is to evaluate the effect of oral cryotherapy on the prevention of oral mucositis and pain among patients with colorectal cancer undergoing fluorouracil-based chemotherapy. METHODS Using an experimental study design, the authors randomly assigned 80 patients to either the intervention (n = 40) or usual care group (n = 40). Intervention group participants received oral cryotherapy in the form of ice chips held in their mouths during chemotherapy infusion. Both groups used sodium bicarbonate mouthwash postchemotherapy until the next cycle. FINDINGS In the usual care group, most participants reported grade 2 (moderate to life-threatening) or greater mucositis. Pain associated with mucositis was lower using oral cryotherapy, with the majority of participants in the intervention group reporting no pain.
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3.
[Update in the diagnostic and therapeutic approach of invasive aspergillosis in adult population].
Rabagliati, R
Revista chilena de infectologia : organo oficial de la Sociedad Chilena de Infectologia. 2018;(5):531-544
Abstract
The invasive fungal disease produced by Aspergillus spp., is the infection by filamentous fungi most frequently reported among immunocompromised individuals and responsible for a very high mortality in this group of patients. In recent years, important advances have been made both from the diagnostic and therapeutic point of view. At present, a series of risk factors associated with its development have been identified, allowing the categorization of patients in high, intermediate and low risk of invasive aspergillosis (IA); and diagnostic criteria have also been established that consider factors of the host, traditional mycological laboratory, biomarkers such as galactomannan and 1→3-β-d-glucan, together with the better understanding and interpretation of the tomographic images that have allowed to reach a consensus on the diagnostic categories. This added to the incorporation of new antifungals and therapeutic strategies in different scenarios, have allowed decreasing the associated mortality. In this review, are updated the epidemiological aspects, the risk factors, the diagnosis, prevention and prophylaxis as well as the therapeutic confrontation, including strategies for the use of empirical, precocious and directed antifungal therapy, as well as the most relevant aspects of the first-choice and alternative antifungals for the IA management.
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4.
Correlation of In Vitro Susceptibility Based on MICs and Squalene Epoxidase Mutations with Clinical Response to Terbinafine in Patients with Tinea Corporis/Cruris.
Khurana, A, Masih, A, Chowdhary, A, Sardana, K, Borker, S, Gupta, A, Gautam, RK, Sharma, PK, Jain, D
Antimicrobial agents and chemotherapy. 2018;(12)
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Abstract
Recalcitrant dermatophytoses are on the rise in India. High MICs of terbinafine (TRB) and squalene epoxidase (SQLE) gene mutations conferring resistance in Trichophyton spp. have been recently documented. However, studies correlating laboratory data with clinical response to TRB in tinea corporis/cruris are lacking. For this study, we investigated the clinicomycological profile of 85 tinea corporis/cruris patients and performed antifungal susceptibility testing by CLSI microbroth dilution and SQLE mutation analysis of the isolates obtained and correlated these with the responses to TRB. Patients confirmed by potassium hydroxide (KOH) mounting of skin scrapings were started on TRB at 250 mg once a day (OD). If >50% clinical clearance was achieved by 3 weeks, the same dose was continued (group 1). If response was <50%, the dose was increased to 250 mg twice a day (BD) (group 2). If the response still remained below 50% after 3 weeks of BD, the patients were treated with itraconazole (ITR; group 3). Overall, skin scrapings from 64 (75.3%) patients yielded growth on culture. Strikingly, all isolates were confirmed to be Trichophyton interdigitale isolates by internal transcribed spacer (ITS) sequencing. Thirty-nine (61%) of the isolates had TRB MICs of ≥1 µg/ml. Complete follow-up data were available for 30 culture-positive patients. A highly significant difference in modal MICs to TRB among the three treatment response groups was noted (P = 0.009). Interestingly, 8 of the 9 patients in group 3 harbored isolates exhibiting elevated TRB MICs (8 to 32 µg/ml) and SQLE mutations. The odds of achieving cure with TRB MIC < 1 µg/ml strains were 2.5 times the odds of achieving cure with the strain exhibiting MIC ≥1 µg/ml.
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5.
Chitosan oligosaccharides affect xanthone and VOC biosynthesis in Hypericum perforatum root cultures and enhance the antifungal activity of root extracts.
Badiali, C, De Angelis, G, Simonetti, G, Brasili, E, Tobaruela, EC, Purgatto, E, Yin, H, Valletta, A, Pasqua, G
Plant cell reports. 2018;(11):1471-1484
Abstract
Water-soluble chitosan oligosaccharides (COS) affect xanthone and volatile organic compound content, as well as antifungal activity against human pathogenic fungi of extracts obtained from Hypericum perforatum root cultures. Several studies have demonstrated the elicitor power of chitosan on xanthone biosynthesis in root cultures of H. perforatum. One of the major limitations to the use of chitosan, both for basic and applied research, is the need to use acidified water for solubilization. To overcome this problem, the elicitor effect of water-soluble COS on the biosynthesis of both xanthones and volatile organic compounds (VOCs) was evaluated in the present study. The analysis of xanthones and VOCs was performed by HPLC and GC-MS headspace analysis. The obtained results showed that COS are very effective in enhancing xanthone biosynthesis. With 400 mg L-1 COS, a xanthone content of about 30 mg g-1 DW was obtained. The antifungal activity of extracts obtained with 400 mg L-1 COS was the highest, with MIC50 of 32 µg mL-1 against Candida albicans and 32-64 µg mL-1 against dermatophytes, depending on the microorganism. Histochemical investigations suggested the accumulation of isoprenoids in the secretory ducts of H. perforatum roots. The presence of monoterpenes and sesquiterpenes was confirmed by the headspace analysis. Other volatile hydrocarbons have been identified. The biosynthesis of most VOCs showed significant changes in response to COS, suggesting their involvement in plant-fungus interactions.
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6.
Fluconazole non-susceptible breakthrough candidemia after prolonged low-dose prophylaxis: a prospective FUNGINOS study.
Orasch, C, Mertz, D, Garbino, J, van Delden, C, Emonet, S, Schrenzel, J, Zimmerli, S, Damonti, L, Mühlethaler, K, Imhof, A, et al
The Journal of infection. 2018;(5):489-495
Abstract
OBJECTIVES Breakthrough candidemia (BTC) on fluconazole was associated with non-susceptible Candida spp. and increased mortality. This nationwide FUNGINOS study analyzed clinical and mycological BTC characteristics. METHODS A 3-year prospective study was conducted in 567 consecutive candidemias. Species identification and antifungal susceptibility testing (CLSI) were performed in the FUNGINOS reference laboratory. Data were analyzed according to STROBE criteria. RESULTS 43/576 (8%) BTC occurred: 37/43 (86%) on fluconazole (28 prophylaxis, median 200 mg/day). 21% BTC vs. 23% non-BTC presented severe sepsis/septic shock. Overall mortality was 34% vs. 32%. BTC was associated with gastrointestinal mucositis (multivariate OR 5.25, 95%CI 2.23-12.40, p < 0.001) and graft-versus-host-disease (6.25, 1.00-38.87, p = 0.05), immunosuppression (2.42, 1.03-5.68, p = 0.043), and parenteral nutrition (2.87, 1.44-5.71, p = 0.003). Non-albicans Candida were isolated in 58% BTC vs. 35% non-BTC (p = 0.005). 63% of 16 BTC occurring after 10-day fluconazole were non-susceptible (Candida glabrata, Candida krusei, Candida norvegensis) vs. 19% of 21 BTC (C. glabrata) following shorter exposure (7.10, 1.60-31.30, p = 0.007). Median fluconazole MIC was 4 mg/l vs. 0.25 mg/l (p < 0.001). Ten-day fluconazole exposure predicted non-susceptible BTC with 73% accuracy. CONCLUSIONS Outcomes of BTC and non-BTC were similar. Fluconazole non-susceptible BTC occurred in three out of four cases after prolonged low-dose prophylaxis. This implies reassessment of prophylaxis duration and rapid de-escalation of empirical therapy in BTC after short fluconazole exposure.
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Limited ERG11 Mutations Identified in Isolates of Candida auris Directly Contribute to Reduced Azole Susceptibility.
Healey, KR, Kordalewska, M, Jiménez Ortigosa, C, Singh, A, Berrío, I, Chowdhary, A, Perlin, DS
Antimicrobial agents and chemotherapy. 2018;(10)
Abstract
Multiple Erg11 amino acid substitutions were identified in clinical isolates of Candida auris originating from India and Colombia. Elevated azole MICs were detected in Saccharomyces cerevisiae upon heterologous expression of C. aurisERG11 alleles that encoded for Y132F or K143R substitutions; however, expression of alleles encoding I466M, Y501H, or other clade-defined amino acid differences yielded susceptible MICs. Similar to other Candida species, specific C. aurisERG11 mutations resulted directly in reduced azole susceptibility.
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8.
The pathogenicity of Aspergillus fumigatus, drug resistance, and nanoparticle delivery.
Szalewski, DA, Hinrichs, VS, Zinniel, DK, Barletta, RG
Canadian journal of microbiology. 2018;(7):439-453
Abstract
The genus Aspergillus includes fungal species that cause major health issues of significant economic importance. These microorganisms are also the culprit for production of carcinogenic aflatoxins in grain storages, contaminating crops, and economically straining the production process. Aspergillus fumigatus is a very important pathogenic species, being responsible for high human morbidity and mortality on a global basis. The prevalence of these infections in immunosuppressed individuals is on the rise, and physicians struggle with the diagnosis of these deadly pathogens. Several virulence determinants facilitate fungal invasion and evasion of the host immune response. Metabolic functions are also important for virulence and drug resistance, since they allow fungi to obtain nutrients for their own survival and growth. Following a positive diagnostic identification, mortality rates remain high due, in part, to emerging resistance to frequently used antifungal drugs. In this review, we discuss the role of the main virulence, drug target, and drug resistance determinants. We conclude with the review of new technologies being developed to treat aspergillosis. In particular, microsphere and nanoparticle delivery systems are discussed in the context of improving drug bioavailability. Aspergillus will likely continue to cause problematic infections in immunocompromised patients, so it is imperative to improve treatment options.
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9.
Successful treatment of Aspergillus ventriculitis through voriconazole adaptive pharmacotherapy, immunomodulation, and therapeutic monitoring of cerebrospinal fluid (1→3)-β-D-glucan.
Chen, TK, Groncy, PK, Javahery, R, Chai, RY, Nagpala, P, Finkelman, M, Petraitiene, R, Walsh, TJ
Medical mycology. 2017;(1):109-117
Abstract
Aspergillus ventriculitis is an uncommon but often fatal form of invasive aspergillosis of the central nervous system (CNS). As little is known about the diagnosis, treatment, and outcome of this potentially lethal infection, we report the strategies used to successfully treat Aspergillus ventriculitis complicating a pineal and pituitary germinoma with emphasis on the critical role of adaptive pharmacotherapy of voriconazole and serial monitoring of (1→3)-β-D-glucan in cerebrospinal fluid. We describe several rationally based therapeutic modalities, including adaptive pharmacotherapy, combination therapy, sargramostim-based immunomodulation, and biomarker-based therapeutic monitoring of the CNS compartment. Through these strategies, our patient remains in remission from both his germinoma and Aspergillus ventriculitis making him one of the few survivors of Aspergillus ventriculitis.
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10.
Antifungal Prevention of Systemic Candidiasis in Immunocompetent ICU Adults: Systematic Review and Meta-Analysis of Clinical Trials.
Dupont, H, Mahjoub, Y, Chouaki, T, Lorne, E, Zogheib, E
Critical care medicine. 2017;(11):1937-1945
Abstract
OBJECTIVES The aim of this study was to identify the impact of antifungal prevention in critically ill immunocompetent adult patients on mortality and subsequent infection. DATA SOURCES A systematic review and meta-analysis of randomized controlled trials comparing any antifungal use versus placebo to prevent candidiasis in ICU patients were performed. STUDY SELECTION Searches were performed on PubMed, Embase, Scopus, main conference proceedings, and ClinicalTrials.gov, as well as reference lists. DATA EXTRACTION The primary outcomes were mortality and invasive candidiasis. The secondary outcome was the rate of Candida albicans and nonalbicans strains after treatment. A random effect model was used, and sensitivity analysis was performed for both outcomes. Results are expressed as risk ratios and their 95% CIs. DATA SYNTHESIS Nineteen trials (10 with fluconazole, four with ketoconazole, one with itraconazole, three with micafungin, and one with caspofungin) including 2,792 patients were identified. No individual trial showed a decreased mortality rate. Combined analysis showed that preventive antifungal did not decrease mortality (risk ratio, 0.88; 95% CI, 0.74-1.04; p = 0.14) but significantly decreased secondary fungal infections by 50% (risk ratio, 0.49; 95% CI, 0.35-0.68; p = 0.0001). No shift across nonalbicans strains was observed during treatment (risk ratio, 0.62; 95% CI, 0.19-1.97; p = 0.42). However, publication biases preclude any definite conclusions for prevention of infection. CONCLUSIONS Antifungal prevention of systemic candidiasis in immunocompetent critically ill adults did not reduce mortality and may have decreased secondary fungal infection rates. However, significant publication bias was present.