In Vitro Susceptibility of Talaromyces Marneffei In Malaysia: Comparison of Yeast and Mycelial Phases

Talaromyces marneffei is an etiologic agent of talaromycosis. It can cause serious complications and death in immunocompromised patients, particularly in acquired immunodeficiency syndrome (AIDS) patients. This infectious disease is endemic in Southeast Asia including Malaysia. To date, published reports on the antifungal susceptibility profile of T. marneffei is very limited. The objective of this study is to determine the minimum inhibitory concentration (MIC) of T. marneffei in yeast and mycelial phases in Malaysia. In the year 2020, 27 clinical strains of T. marneffei were received from various hospitals in Malaysia. The identification was carried out using microscopic, macroscopic and molecular methods. Following that, the susceptibility of each isolate in both yeast and mycelial form to thirteen common antifungals was performed according to the broth microdilution in Clinical & Laboratory Standards Institute (CLSI) M38 method. The antifungals tested were anidulafungin, micafungin sodium, caspofungin diacetate, 5-fluorocytosine, amphotericin B and terbinafine hydrochloride, posaconazole, voriconazole, itraconazole, ketoconazole, ravuconazole, clotrimazole and isavuconazole. The geometric mean of all antifungals other than anidulafungin, micafungin sodium, caspofungin diacetate and 5-fluorocytosine against T. marneffei mould (mycelial) were >2 μg/ml. However, the geometric mean of all antifungals against T. marneffei yeast was <2 μg/ml. Our in vitro data suggests promising activities of amphotericin B, terbinafine hydrochloride, posaconazole, voriconazole, itraconazole, ketoconazole, ravuconazole, clotrimazole and isavuconazole against yeast and mould phases of T. marneffei.

Diversity of Endophytic fungi in liana, Celastrus paniculatus collected from few sites of Jhargram and Paschim Medinipur districts, West Bengal, India

To determine the identity and diversity of endophytic fungi associated with the liana from five different forest localities of Jhargram and West Medinipur districts of West Bengal. On the basis of differentiation of weather and microclimate, I have to select the regions. Between the two regions, the distance is at least 25-30 km, the microclimate and moisture under the canopy will differ, it affects mainly on the presence of endophytes. Leaf, fruit and stem segments were collected randomly in summer, winter and monsoon in 2018. It is impossible to take all leaves and other organs of a plant because plant parts should be collected sustainably so that minimum damage of stock occurs. Surfaces of all samples were sterilised just before putting on pot5ato dextrose agar (PDA) media for the growth of endophytic fungal mycelia and their isolation. Fungi were isolated and identified based on the morphology of its colony, and mycelial form and morphology, sexual and asexual reproductive structures and their characters, spore-form and nature of attachment, cultural conditions etc. were taken in consideration to identify them. Total 1125 samples were used for endophytic growth. The total of 1558 endophytic fungi were isolated from 797 sample segments of Celastrus paniculatus. The dominant endophytic fungi belong to genera Fusarium sp., Aspergillus sp., Chaetomium sp., Beltrania sp., Pestalotiopsis sp., Verticillium sp., Arthrinium sp, Penicillium sp., Podospora sp., Alternarium sp., Acrocylindrium sp. etc. Maximum endophytic isolates were obtained from leaf segments followed by fruit and then stem. In monsoon, colonization frequency shows highest (80.53%) and in summer, it is lowest (61.87%) from the plant samples of all locations. The examples from Chilkigarh shows the highest colonization frequency (90.22%) and from Nayagram, it is the lowest (61.78%). The leaf’s colonization frequency is maximum (84.53%) and the stem is minimum (62.4%). Most of the isolated endophytic fungi were found under the group Deuteromycetes. Endophytic fungi show a wide range of Shannon-Weiner and Simpson’s indices. These indicators point to an equal and throughout distribution of different species. The findings add to our knowledge of the identity and diversity of endophytic fungi, which are expected to have a variety of interactions with their host plants.

Molecular Tools for Detection and Identification of Paracoccidioides Species: Current Status and Future Perspectives

Paracoccidioidomycosis (PCM) is a mycotic disease caused by the Paracoccidioides species, a group of thermally dimorphic fungi that grow in mycelial form at 25 °C and as budding yeasts when cultured at 37 °C or when parasitizing the host tissues. PCM occurs in a large area of Latin America, and the most critical regions of endemicity are in Brazil, Colombia, and Venezuela. The clinical diagnosis of PCM needs to be confirmed through laboratory tests. Although classical laboratory techniques provide valuable information due to the presence of pathognomonic forms of Paracoccidioides spp., nucleic acid-based diagnostics gradually are replacing or complementing culture-based, biochemical, and immunological assays in routine microbiology laboratory practice. Recently, taxonomic changes driven by whole-genomic sequencing of Paracoccidioides have highlighted the need to recognize species boundaries, which could better ascertain Paracoccidioides taxonomy. In this scenario, classical laboratory techniques do not have significant discriminatory power over cryptic agents. On the other hand, several PCR-based methods can detect polymorphisms in Paracoccidioides DNA and thus support species identification. This review is focused on the recent achievements in molecular diagnostics of paracoccidioidomycosis, including the main advantages and pitfalls related to each technique. We discuss these breakthroughs in light of taxonomic changes in the Paracoccidioides genus.

The assimilation of different carbon sources in Candida albicans: Fitness and pathogenicity

Candida albicans is a commensal yeast commonly found on the skin and in the body. However, in immunocompromised individuals, the fungi could cause local and systemic infections. The carbon source available plays an important role in the establishment of C. albicans infections. The fungi's ability to assimilate a variety of carbon sources plays a vital role in its colonization, and by extension, its fitness and pathogenicity, as it often inhabits niches that are glucose-limited but rich in alternative carbon sources. A difference in carbon sources affect the growth and mating of C. albicans, which contributes to its pathogenicity as proliferation helps the fungi colonize its environment. The carbon source also affects its metabolism and signaling pathways, which are integral parts of the fungi's fitness and pathogenicity. As a big percentage of the carbon assimilated by C. albicans goes to cell wall biogenesis, the availability of different carbon sources will result in cell walls with variations in rigidity, adhesion, and surface hydrophobicity. In addition to the biofilm formation of the fungi, the carbon source also influences whether the fungi grow in yeast- or mycelial-form. Both forms play different roles in C. albicans’s infection process. A better understanding of the role of the carbon sources in C. albicans’s pathogenicity would contribute to more effective treatment solutions for fungal infections.

Diagnosis of human sporotrichosis in Campos dos Goytacazes, Rio de Janeiro, Brazil

Introduction: Sporotrichosis is an infectious fungal zoonosis associated with traumatic implantation in the skin of dimorphic fungi of the Sporothrix schenckii complex. The objective of this study was to diagnose sporotrichosis in patients in the city of Campos dos Goytacazes, and to establish correlations between positive laboratory results and dermatological and topographical aspects of the lesions and personal traits of the patients, such as sex, age and profession. Methodology: We collected samples from 22 patients with suspect lesions, which were sent to the laboratory for direct microscopic analysis after Gram staining, followed by mycological culture by seeding the material in 4% Sabouraud dextrose agar (Himedia®) supplemented with chloramphenicol (50 mg/Lt) and cycloheximide (400 mg/Lt - Sigma-Aldrich, USA). The dishes were incubated at 25-30oC. For confirmation of the diagnosis, the strains isolated in mycelial form were converted to yeast form by culture in yeast-peptone-dextrose (YPD) agar at 37oC for up to 15 days. Results: The positive results demonstrated that the disease was most frequently diagnosed in women between the ages of 19 and 60 years, and that 18 (81.8%) of the patients reported having contact with pet cats. The occupations of those positive for sporotrichosis were not related to the disease. The upper limbs were the body region most often afflicted, with observation in the majority of cases of ulcerated lesions, although five patients also had nodular lesions. Additionally, the observation of lymphatic cords was frequent. Conclusion: In recent years, sporotrichosis has been diagnosed with relative frequency in Campos dos Goytacazes, causing great concern among public health officials and practitioners.

Antigenotoxic Properties ofAgaricus blazeiagainst Hydrogen Peroxide in Human Peripheral Blood Cells

The ability ofAgaricus blazeimushroom in its dried and powdered mycelial form was evaluated for its antigenotoxic properties for the first time. Antigenotoxic effects in human peripheral blood cells against H2O2-induced DNA damage were examined in pretreatment and posttreatment protocol by comet assay. The results showed better antigenotoxic properties ofAgaricus blazeion the interventional level, respectively, after treatment.Agaricus blazeiin concentration of 250 μg/mL after treatment was most efficient in regard to its action against DNA damage. The evaluation of repair kinetics showed decrease in H2O2induced DNA damage 15 min after the application ofA. blazei, reaching the maximum potency after 30 min. Analysis of antioxidant properties ofAgaricus blazeirevealed strongOH•scavenging properties and moderate reducing power, while its DPPH scavenging ability was weak. In regard to our findings, we can conclude that our preliminary results demonstrated antigenotoxic properties ofAgaricus blazeiand its strongOH•scavenging ability. Mechanisms underlying its properties should be further evaluated in in vivo studies.