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Malassezia spp. Yeasts of Emerging Concern in Fungemia
Get PDFMalassezia spp. are lipid-dependent yeasts, inhabiting the skin and mucosa of humans
and animals. They are involved in a variety of skin disorders in humans and animals and
may cause bloodstream infections in severely immunocompromised patients. Despite a
tremendous increase in scientific knowledge of these yeasts during the last two decades,
the epidemiology of Malassezia spp. related to fungemia remains largely underestimated
most likely due to the difficulty in the isolation of these yeasts species due to their
lipid-dependence. This review summarizes and discusses the most recent literature
on Malassezia spp. infection and fungemia, its occurrence, pathogenicity mechanisms,
diagnostic methods,in vitro susceptibility testing and therapeutic approache
In Vitro Azole and Amphotericin B Susceptibilities of Malassezia furfur from Bloodstream Infections Using E-Test and CLSI Broth Microdilution Methods
No full textThe number of reports of Malassezia furfur bloodstream infections is constantly increasing and there is a need for more simple antifungal susceptibility methods for their management. In this study, a total of 39 M. furfur isolates collected from hospitalized patients with fungemia were screened for antifungal susceptibility to azole and amphotericin B (AmB) using Clinical and Laboratory Standards Institute broth microdilution (CLSI BMD) and E-test in Sabouraud dextrose agar + 1% Tween80 (SDAt) and mDixon agar (DIX). Essential agreement (EA) and discrepancies between the two methods were evaluated after 48 h and 72 h reading times. Itraconazole (ITZ) and posaconazole (POS) displayed the lowest MIC values whereas fluconazole (FLZ) and AmB the highest, regardless of the methods and the reading time. The EA between BMD was >95% for FLZ and voriconazole (VOR) regardless of the media in the E-tests and reading time. The EA between BMD with E-test for AmB was >97% only when E-test in SDAt was used. The EA between BMD and E-test for ITZ and POS varied according to the media in E-test procedures and the reading time and was higher than 66.6% (POS) or 72% (ITZ) only when SABt was used. Substantial discrepancies for ITZ and POS were >5.1% regardless of the media and the reading time. This study suggests that the E-test in SABt represents an alternative method to CLSI BMD to evaluate the susceptibility of M. furfur to FLZ, VOR and AmB and not for ITZ and POS
Role of lizards as reservoirs of pathogenic yeasts of zoonotic concern
No full textReptiles have become popular exotic pets and in some parts of the world, they are used as important source of food, medicines, and materials. Synanthropic lizards are recognized as reservoirs of viruses, bacteria, and parasites but their role in dissemination of zoonotic pathogenic yeasts in the environment was never investigated. Therefore, fecal samples (n=177) from Podarcis siculus (Italian wall lizard), Chalcides ocellatus (Ocellated skink) and Tarentola mauritanica (Moorish gecko) were collected and yeasts were isolated and identified biochemically and molecularly by sequencing the rDNA internal transcribed spacer region (ITS). The phylogenetical relationship of isolated yeast species and their antifungal susceptibility profiles to ten antifungal agents were also assessed. Sixty samples (n=60/177; 33.9%) scored positive for yeasts, with the highest occurrence in C. ocellatus (n=11/17; 64.7%) and the highest variety of species in P. siculus (n=11/12; 91.6%). A total of 364 isolates belonging to Candida, Trichosporon, Saccharomyces and Geotrichum genera were molecularly identified. In particular, Candida albicans (n=160; 44%) followed by Trichosporon coremiiforme (n=44; 12.1%), Pichia kudriavzevii (n=32; 8.8%) and Trichosporon asahii (n=28; 7.7%) were the most frequently isolated species. The phylogenetic tree grouped all representative sequence types within the clade including Candida spp. strains from different geographical areas and from animal species, including human. All tested strains showed high susceptibility to the assayed antifungal drugs. This study suggests the role of lizards as reservoirs and spreaders of zoonotic pathogenic yeasts in the environment. The absence of resistance phenomena in the isolated yeasts might reflect an environment free of azole antifungal pollution or chemicals, suggesting the usefulness of these animals as bio indicators of environment quality
Beauveria bassiana delivered through a cellulose-based hydrogel is effective against the red poultry mite, Dermanyssus gallinae
No full textThough the entomopathogenic fungus Beauveria bassiana has shown to be efficacious for managing Dermanyssus gallinae infestations, its delivery as liquid formulation poses concerns related to environmental stability and efficacy. To overcome such concerns, here we proposed a hydrogel matrix based on hydroxyethyl-cellulose (HEC) for delivering B. bassiana to control D. gallinae. Nymph and adult mites were exposed to a hydrogel matrix or filter papers containing B. bassiana (107 conidia/mL), with and without a pre-incubation period of 4 days at 25 °C (treated groups). As control groups, mites were exposed to hydrogel matrix or filter papers with sterile distilled water. Results showed higher mortality of all stages of D. gallinae in treated groups compared to respective control groups. The LT50 and LT90 estimated on D. gallinae were lower in treated groups (LT50 ≤ 9.5 days for adults; and LT50 ≤ 10.7 days for nymphs; LT90 ≤ 14.9 for adults; LT90 ≤ 17.9 days for nymphs) than in control groups (LT5 0 ≥14.9 days for adults, LT50 > 19 days for nymphs; LT90 > 20 days for adults and nymphs). Pre-incubation significantly reduced LT50 and LT90 with respect to other treated groups. Overall, our study outlined that the conidial suspension of B. bassiana in hydrogel is efficacious against both nymphs and adults of D. gallinae. The pre-incubation of B. bassiana in the HEC enhanced its efficacy. Thus, delivering B. bassiana through HEC-based hydrogel matrix may represent an effective and sustainable solution for managing D. gallinae infestations in the poultry industry
Chemical Composition, Antibacterial and Antifungal Activities of Crude Dittrichia viscosa (L.) Greuter Leaf Extracts
Get PDFThe small amount of data regarding the antifungal activity of Dittrichia viscosa (L.) Greuter against dermatophytes, Malassezia spp. and Aspergillus spp., associated with the few comparative studies on the antimicrobial activity of methanolic, ethanolic, and butanolic extracts underpins the study herein presented. The total condensed tannin (TCT), phenol (TPC), flavonoid (TFC), and caffeoylquinic acid (CQC) content of methanol, butanol, and ethanol (80% and 100%) extracts of D. viscosa were assessed and their bactericidal and fungicidal activities were evaluated. The antibacterial, anti-Candida and anti-Malassezia activities were evaluated by using the disk diffusion method, whereas the anti-Microsporum canis and anti-Aspergillus fumigatus activities were assessed by studying the toxicity effect of the extracts on vegetative growth, sporulation and germination. The methanolic extract contained the highest TPC and CQC content. It contains several phytochemicals mainly caffeoylquinic acid derivatives as determined by liquid chromatography with photodiode array and electrospray ionisation mass spectrometric detection (LC/PDA/ESI-MS) analysis. All extracts showed an excellent inhibitory effect against bacteria and Candida spp., whereas methanolic extract exhibited the highest antifungal activities against Malassezia spp., M. canis and A. fumigatus strains. The results clearly showed that all extracts, in particular the methanolic extract, might be excellent antimicrobial drugs for treating infections that are life threatening (i.e., Malassezia) or infections that require mandatory treatments (i.e., M. canis or A. fumigatus)
Effect of chlorogenic and gallic acids combined with azoles on antifungal susceptibility and virulence of multidrug-resistant Candida spp. and Malassezia furfur isolates
No full textChlorogenic acid (CHA) and gallic acid (GA) are safe natural phenolic compounds that are used as enhancers of some drugs in influencing antioxidant, anticancer, and antibacterial activities. Among fungi, Candida spp. and Malassezia spp. are characterized by an increasing prevalence of multidrug resistance phenomena and by a high morbidity and mortality of their infections. No data are available about the efficacy of CHA and GA combined with azoles on the antifungal susceptibility and on the virulence of both fungi. Therefore, their antifungal and antivirulence effects have been tested in combination with fluconazole (FLZ) or ketoconazole (KTZ) on 23 Candida spp. and 8 M. furfur isolates. Broth microdilution chequerboard, time-kill studies, and extracellular enzymes (phospholipase and hemolytic) activities were evaluated, displaying a synergistic antifungal action between CHA or GA and FLZ or KTZ on C. albicans, C. bovina, and C. parapsilosis, and antagonistic antifungal effects on M. furfur and Pichia kudriavzevii (Candida krusei) isolates. The time-kill studies confirmed the chequerboard findings, showing fungicidal inhibitory effect only when the GA was combined with azoles on Candida strains. However, the combination of phenolics with azoles had no effect on the virulence of the tested isolates. Our study indicates that the combination between natural products and conventional drugs could be an efficient strategy for combating azole resistance and for controlling fungistatic effects of azole drugs
Dittrichia viscosa L. leaves lipid extract: An unexploited source of essential fatty acids and tocopherols with antifungal and anti-inflammatory properties
No full textDittrichia viscosa L. is considered underexploited species rich on bioactive compounds. Previous investigations focused on phytochemical constituents and their bioactivities have been frequently carried out but the data on fatty acid composition of D. viscosa leaves lipid extract (LLE) and on their antifungal and anti-inflammatory activities are scant. In this study, the fatty acids profile and tocopherols composition of D. viscosa LLE were assessed by using gas chromatography (GC-FID), gas chromatography-mass spectrometry (GCâMS) and by high-performance liquid chromatography (HPLC). The antifungal activity was determined by measuring the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of Candida spp. and Malassezia spp. strains and the anti-inflammatory effect by measuring the elastase inhibitory activity. The linoleic and linolenic acids were the most abundant essential fatty acids while α-tocopherol and Î ́-tocopherol were the most dominant tocopherols. LLE showed excellent antifungal activity against yeasts with low azole susceptibilities (i.e., Malassezia spp. and Candida krusei) and a good anti-inflammatory effect reaching a 72.9% of inhibition of elastase activity using 10 mg of LLE. The results show that lipid extract of D. viscosa leaves could be considered as an exceptional source of essential fatty acids (i.e., linoleic and the linolenic acids) and tocopherols (α-tocophérol and Î ́-tocophérol) and suggests the important value of this extract as new source to control Candida and Malassezia infections as well as inflammatory diseases
Antifungal, Antioxidant and Antibiofilm Activities of Essential Oils of Cymbopogon spp.
No full textEssential oils (EOs) of Cymbopogon citratus and Cymbopogon proximus are known as sources of monoterpenes and sesquiterpenoids, although their biological activities have not been well investigated. In this study, the compositions of C. citratus and C. proximus EOs of Egyptian origin and their antifungal and antibiofilm properties against Candida spp. and Malassezia furfur were investigated. Antioxidant activities were also evaluated. GC-MS showed the presence of nine and eight constituents in C. citratus and C. proximus EOs, respectively, with geranial and neral as the major compounds of C. citratus EO and piperitone and α-terpinolene as the major compounds of C. proximus EO. Both EOs showed antifungal (MIC values ranging from 1.25 to 20 µL/ mL) and antibiofilm activities (% of reduction ranging from 27.65 ± 11.7 to 96.39 ± 2.8) against all yeast species. The antifungal and antibiofilm activities of C. citratus EO were significantly higher than those observed for C. proximus EO. M. furfur was more susceptible to both EOs than Candida spp. Both EOs exhibited the highest antioxidant activity. This study suggests that C. citratus and C. proximus EOs might be an excellent source of antifungal, antibiofilm and antioxidant drugs and might be useful for preventing Malassezia infections in both medical and veterinary medicine
Susceptibility of Rhipicephalus rutilus ticks from dogs to different acaricides
No full textBrown dog ticks (Rhipicephalus sanguineus sensu lato) are widespread ectoparasites of dogs and may also infest other vertebrate hosts, including humans. The control of these ticks is primarily carried out using acaricides. In this study, we assessed the susceptibility of Rhipicephalus rutilus to different acaricides (i.e., amitraz, fipronil, ivermectin, and permethrin). Engorged female ticks (n = 36) were divided into three groups based on their origin (i.e., G1 – untreated dogs from a private shelter; G2 – permethrin-treated private dog shelter; and G3 - fipronil, amitraz, and (S)-methoprene treated owned dogs) and kept under controlled temperature and humidity for oviposition. The acaricidal effects of amitraz (AMZ), fipronil (FIP), ivermectin (IVM), and permethrin (PTR) against R. rutilus were evaluated using the larval packet test, with subgroups of tick larvae in each experimental assay. Our data indicate that R. rutilus larvae from all dog groups were susceptible to IVM. In particular, larvae from G1 were apparently susceptible to IVM and PTR, and tolerant to AMZ and FIP; larvae from G2 were susceptible to FIP and IVM and resistant to AMZ and PTR, while larvae from G3 were susceptible to AMZ, PTR and IVM, and resistant to FIP. These results confirm the occurrence of resistance to AMZ, PTR, and FIP in R. rutilus larvae from southern Italy. This suggests the need to monitor acaricide resistance in brown dog ticks in southern Europe to develop better strategies for the long-term control of ticks in this region
Candida auris from the Egyptian cobra: Role of snakes as potential reservoirs
No full textCandida auris represents one of the most urgent threats to public health, although its ecology remains largely unknown. Because amphibians and reptiles may present favorable conditions for C. auris colonization, cloacal and blood samples (n = 68), from several snake species, were cultured and molecularly screened for C. auris using molecular amplification of glycosylphosphatidylinositol protein-encoding genes and ribosomal internal transcribed spacer sequencing. Candida auris was isolated from the cloacal swab of one Egyptian cobra (Naja haje legionis) and molecularly identified in its cloaca and blood. The isolation of C. auris from wild animals is herein reported for the first time, thus suggesting the role that these animals could play as reservoirs of this emerging pathogen. The occurrence of C. auris in blood requires further investigation, although the presence of cationic antimicrobial peptides in the plasma of reptiles could play a role in reducing the vitality of the fungus.Candida auris represents one of the most urgent threats to public health. In this study, we reported for the first time the isolation of C. auris from snake thus suggesting the role of these animals as reservoirs of this emerging pathogen
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