Phaeohyphomycosis: A study from tertiary health care center in North India

Objectives: Phaeohyphomycosis refers to infections caused by phaeoid/dematiaceous or darkly pigmented fungi. This study was undertaken to further increase our knowledge about the incidence of phaeohyphomycosis and its causative agents. Materials and Methods: The present study was conducted over a period of one and a half years (January 2018–June 2019) on specimens received from patients with varied clinical manifestations ranging from superficial infections, subcutaneous cysts, pneumonia, brain abscess to a disseminated infection. These specimens were processed in the Department of Microbiology for potassium hydroxide (KOH) examination and culture and in Pathology for cytology/histopathological examination (HPE). All specimens positive on direct examination for dark grey, brown or black fungi were included in the study. Results: A total of 20 specimens were confirmed as phaeohyphomycosis. Most of the patients belonged to the age group of 41 to 50 years. Male: Female ratio was 2.3:1. Trauma was the most common risk factor. Spectra of the isolated fungal pathogens comprised of Bipolaris species, Exophiala species, Curvularia geniculata, Phialemonium species, Daldinia eschscholtzii, Hypoxylon anthochroum, Phaeoacremonium species, Leptosphaerulina australis, Medicopsis romeroi, Lasiodiplodia theobromae, Eutypella species, Chaetomium globosum, Alternaria species, Cladophialophora bantiana and 2 unidentified dematiaceous fungi. Recovery from phaeohyphomycosis was seen in 12 patients, 7 were lost to follow up and one patient succumbed to the illness. Conclusion: Infections caused by phaeoid fungi can no longer be viewed as rare. In fact, phaeohyphomycosis can have myriad of presentations spanning from mild cutaneous infections to fatal brain disease. Therefore, a high index of clinical suspicion is needed to diagnose such infections. The primary treatment modality remains surgical removal of the lesion in cutaneous or subcutaneous infections however disseminated disease with a guarded prognosis requires aggressive management.

Phenotypic Characterization of Fungal Pathogens Associated with the Main Mycoses of Cashew (Anacardium occidentale L.)

Aims: To study the diversity of fungal pathogens associated with cashew mycoses in Togo. Study Design: This research project was initiated by the Mycology Research and Applications Unit of the Botany and Plant Ecology Laboratory (LBEV) in order to have adequate information on cashew mycoses in Togo. Place and Duration of Study: Laboratory of Botany and Plant Ecology (LBEV) of the University of Lome (UL) and of Crop Protection and Biosafety Laboratory of Togolese Institute of Agronomic Research (ITRA), February to August 2020. Methodology: A total of 148 symptomatic samples (leaves, buds, inflorescences, nuts, and apples) were collected from cashew trees in the East Mono prefecture of Togo. Malt-agar medium supplemented with chloramphenicol at 0.5 g/l was used for the isolation of fungal pathogens. The characterization of these fungal pathogens was carried out from the 7th day based on their macroscopic (texture, color, diameter of growth) and microscopic (hypha, spore, fruiting body) characters. Results: This study revealed the presence of five mycoses in cashew orchards in the East Mono prefecture. These are leaf anthracnose, bud’s dieback, black rust, leaf yellowing, and powdery mildew. In total, 12 fungal genera were encountered and 14 species of fungal pathogens were identified on all the samples collected: Rhizopus sp., Penicillium sp., Mucor sp., Sporotrichum sp., Fusarium nivale, Fusarium moliniforme, Fusarium moliniforme var. subglutinans, Curvularia lunata, Curvularia geneculata, Alternaria tenuissima, Alternaria brassicisola, Beltrania rhombica Penz., Thielavia coactilis Nicot, Helminthosporium avenae, Helminthosporium siccans, Phoma eupyrena, Aspergillus flavus, Aspergillus niger. Conclusion: It would be of great interest to train cashew producers in the East Mono prefecture on the recognition of the symptoms of these mycoses and their management.

Biocontrol potential of endophytic fungi in tea (Camellia sinensis (L.) Kuntze) leaves against selected fungal phytopathogens

Aims@#Endophytic fungi are a diverse group of microorganisms that stay asymptomatically in the healthy tissues of the host. Many fungal endophytes are associated with the tea plant (Camellia sinensis) and the pathogens of the tea plant have the potential to grow as endophytes or act as latent pathogens during the initial growth of the plant. The present study aimed at screening tea endophytic fungi with the potential for control of a few critical phytopathogens, Fusarium sp., Lasiodiplodia theobromae, Pestalotiopsis sp. and Sclerotinia sclerotiorum while evaluating the efficiency of growth inhibition of these phytopathogens by the endophytic fungal isolates using in vitro assays.@*Methodology and results@#Five endophytic fungal strains; Colletotrichum gloeosporioides, C. siamense, Daldinia eschscholtzii, Pseudopestalotiopsis chinensis and Phyllosticta capitalensis isolated from leaves of C. sinensis in Sri Lanka were evaluated for growth inhibition against plant pathogens; Fusarium sp., L. theobromae, Pestalotiopsis sp. and S. sclerotiorum using the dual culture assay and volatile compound-mediated inhibition assay. All the fungal endophytes used in this study exhibited antifungal activity against Fusarium sp., Pestalotiopsis sp. and S. sclerotiorum in the dual culture assay on PDA. Daldinia eschscholtzii (67.30%) and C. gloeosporioides (61.54%) showed strong antagonistic activity against S. sclerotiorum, while P. capitalensis (42.30%) demonstrated moderate activity. All the endophytic fungal strains showed moderate antifungal activities against Fusarium sp. The percentage growth inhibitions of Pestalotiopsis sp. by all the endophytic isolates tested were below 25.00%. In the volatile compound-mediated inhibition assay, none of the endophytic isolates showed visible inhibition against the phytopathogens used.@*Conclusion, significance and impact of study@#In this study, the fungal endophytes which showed potential antagonistic activity against the tested phytopathogens can be used to develop commercialized products of fungal biocontrol agents (BCAs) for controlling plant fungal diseases.

Growth supression of plant pathogenic fungi using bryophite extracts / Supressão de crescimento de fungos patogênicos de plantas usando extratos de briófitas

Chemicals are often used in attempts to control diseases caused by plant pathogenic fungi during food production. However, chemicals can have adverse effects not just on food, but they also remain active for a long time within ecosystems, and thus are not environmentally friendly. Therefore,development of bio-treatment and avoiding use of chemicals are urgently needed. With the aim of studying and developing new environmentally-friendly treatments, we tested extracts from selected bryophyte species(Porella platyphylla, Cinclidotus fontinaloides and Anomodon viticulosus) on five plant pathogenic fungi under controlled conditions. The fungi (Botryosphaeria dothidea, Phomopsis viticola, Calosphaeria sp., Colletotrichum acutatum and Monilinia laxa) were selected based on common diseases they cause on fruits and grapevine. They were isolated in cultures and treated with bryophyte extracts. Bryophyte extracts were shown to be effective in suppression of certain plant pathogenic fungi growth and to have a huge potential in development of novel biotechnological treatments and biofungicides. The best results were achieved in inhibition of B. dothidea, P. viticola and Calosphaeria sp.

Fungos fitopatogênicos são controlados com produtos químicos para combater doenças causadas por eles durante a produção de alimentos. Tais produtos são ruins não apenas para a alimentação, mas também podem permanecer por muito tempo nos ecossistemas, portanto, não são ecologicamente corretos. Desta forma, os biotratamentos e a prevenção de usos químicos são urgentemente necessários no futuro próximo. Com o objetivo de estudar e desenvolver nova alternative decontrole de doenças de plantas, testamos os extratos de espécies de briófitas selecionadas (Porella platyphylla, Cinclidotus fontinaloides e Anomodon viticulosus) em cinco fungos fitopatogênicos (Botryosphaeria dothidea, Phomopsis viticola, Calosphaeria sp., Colletotrichum acutatum e Monilinia laxa) em condição controlada. Estes fungos, selecionados com base nas doenças que causam em frutos e videiras, foram isolados em culturas puras e tratados com os respectivos extratos de briófitas. Os extratos de briófitas demonstraram ser eficazes na supressão de certos fungos fitopatogênicos e têm um enorme potencial no desenvolvimento de novos biofungicidas e tratamentos biotecnológicos. Os mais interessantes resultados foram obtidos na inibição de B. dothidea, P. viticola eCalosphaeria sp.

Is the emergence of fungal resistance to medical triazoles related to their use in the agroecosystems? A mini review

Abstract Triazole fungicides are used broadly for the control of infectious diseases of both humans and plants. The surge in resistance to triazoles among pathogenic populations is an emergent issue both in agriculture and medicine. The non-rational use of fungicides with site-specific modes of action, such as the triazoles, may increase the risk of antifungal resistance development. In the medical field, the surge of resistant fungal isolates has been related to the intensive and recurrent therapeutic use of a limited number of triazoles for the treatment and prophylaxis of many mycoses. Similarities in the mode of action of triazole fungicides used in these two fields may lead to cross-resistance, thus expanding the spectrum of resistance to multiple fungicides and contributing to the perpetuation of resistant strains in the environment. The emergence of fungicide-resistant isolates of human pathogens has been related to the exposure to fungicides used in agroecosystems. Examples include species of cosmopolitan occurrence, such as Fusarium and Aspergillus, which cause diseases in both plants and humans. This review summarizes the information about the most important triazole fungicides that are largely used in human clinical therapy and agriculture. We aim to discuss the issues related to fungicide resistance and the recommended strategies for preventing the emergence of triazole-resistant fungal populations capable of spreading across environments.

Isolation of Fungal Pathogens to an Edible Mushroom, Pleurotus eryngii, and Development of Specific ITS Primers

Fungal pathogens have caused severe damage to the commercial production of Pleurotus eryngii, the king oyster mushroom, by reducing production yield, causing deterioration of commercial value, and shortening shelf-life. Four strains of pathogenic fungi, including Trichoderma koningiopsis DC3, Phomopsis sp. MP4, Mucor circinelloides MP5, and Cladosporium bruhnei MP6, were isolated from the bottle culture of diseased P. eryngii. A species-specific primer set was designed for each fungus from the ITS1-5.8S rDNA-ITS2 sequences. PCR using the ITS primer set yielded a unique DNA band for each fungus without any cross-reaction, proving the validity of our method in detection of mushroom fungal pathogens.

Isolation of siderophore- producing strains of rhizobacterial fluorescent pseudomonads and their biocontrol against rice fungal pathogens.

Rice blast caused by Magnaporthe grisea and sheath blight caused by Rhizoctonia solani are the major diseases affecting the rice production. Application of beneficial bacteria as seed or seedling root dip to protect these diseases may be an alternative strategies to chemical control. In this study, fluorescent Pseudomonads isolated from rice seedlings were used to screen for their antagonistic ability and siderophore mediated antibiosis under in-vitro conditions against these pathogens. Among 10 isolates, strain P.f 003 gave significantly higher inhibition of mycelial growth of M. grisea and R. solani. Strains of P.f 001, P.f 003, P.f 005 and P.f 007 produced siderophores when grown on Fe deficient and Fe fortified King’s B medium. These strains again tested for their in-vitro antagonistic activity against M. grisea and R. solani on King’s B media with or without FeCl3. Our results showed that all these strains significantly reduced the growth of M. grisea and R. solani with FeCl3 in the media compared to without FeCl3. Strain P.f 003 activity was superior compared to other strains evaluated.

Road-killed wild animals: a preservation problem useful for eco-epidemiological studies of pathogens

Road-killed wild animals have been for years used for surveillance of vectors of zoonotic pathogens and may offer new opportunities for eco-epidemiological studies. In the current study, fungal infection was evaluated by PCR and nested-PCR in tissue samples collected from 19 road-killed wild animals. The necropsies were carried out and samples were collected for DNA extraction. Results, using PCR with a panfungal primer and nested PCR with specific primers, indicated that some animals are naturally infected with Amauroascus aureus, Metarhizium anisopliae, Aspergillus flavus, Aspergillus oryzae, Emmonsia parva, Paracoccidioides brasiliensis or Pichia stipitis. The approach employed herein proved useful for detecting the environmental occurrence of several fungi, as well as determining natural reservoirs in wild animals and facilitating the understanding of host-pathogen relationships.

In vitro effects of garlic (allium sativum l.) And african basil (ocimum gratissimum l.) On pathogens isolated from rotted cassava roots / Efectos in vitro del ajo (Allium Sativum L.) Y Albahaca africana (Ocimum Gratissimum L.) Sobre patógenos aislados de raíces de yuca podrida / Efeitos in vitro do alho (Allium Sativum l.) E Alfavaca-Cravo (Ocimum Gratissimum L.) Sobre patógenos isolados de raízes de mandioca podre

Six fungal pathogens causing rot in post-harvest cassava tuberous roots were investigated in vitro for the study of the fungi toxic effects of Allium sativum (L) and Ocimum gratissimum (L.) using aqueous extraction methods. Fungi were isolated by cutting rotted tissue at the interface between healthy and infected portions of the root. Pathogenicity tests revealed that Fusarium oxysporum, F. solani, Botryodiplodia theobromae, Macrophomina phaseolina, Penicillium oxalicum and Aspergillus niger induced rot in healthy cassava tubers after 8 days of re-inoculation, with P. oxalicum as the most virulent. Four different extract concentrations were obtained from each plant part by blending 25, 50, 75 and 100g in 100ml of sterile distilled water (SDW).The fungi toxic effect of the extracts showed that A. sativum had effective inhibition (25.2-86.9%) on mycelial growth of all tested fungi, while extracts of O. gratissimum showed slight to moderately effective inhibition (0.9 to 64.5%) on mycelial growth of all fungi, with the exception of B. theobromae and M. phaseolina, which showed the lowest percentage of inhibition with both plant extracts. The most toxic effect of the extracts was observed with A. sativum at 10%, with significant (P<0.01) inhibition on all fungi tested. The study showed the potential of crude extracts of A. sativum and O. gratissimum on fungal pathogens affecting cassava. This potential of the crude extract of these plants provides an alternative to farmers to reduce and control cassava rot, since they are inexpensive, non-phytotoxic and easy to prepare.

Seis hongos patógenos causantes de pudrición post-cosecha en raíces de yuca fueron investigados in vitro para estudiar los efectos funguitóxicos de Allium sativum (L) y Ocimum gratissimum (L) utilizando métodos de extracción acuosa. Los hongos fueron aislados cortando tejido enfermo en la interfase entre las partes sana e infectada de la raíz. Pruebas de patogenicidad mostraron que Fusarium oxysporum, F. solani, Botryodiplodia theobromae, Macrophomina phaseolina, Penicillium oxalicum y Aspergillus niger inducen pudrición en tubérculos sanos de yuca tras 8 días de reinoculación, siendo P. oxalicum el más virulento. Cuatro concentraciones de extracto fueron obtenidas de cada planta mezclando 25, 50, 75 o 100g con 100ml de agua destilada estéril. El efecto funguitóxico de los extractos mostró que A. sativum produjo una inhibición efectiva (25,2-56,9%) del crecimiento micelial de todos los hongos ensayados, mientras que los extractos de O. gratissimum mostraron débil a moderadamente efectiva inhibición (0,9 a 64,5%) del crecimiento micelial de todos los hongos con excepción de B. theobromae y M. phaseolina, que mostraron el menor porcentaje de inhibición con ambos extractos. El efecto más tóxico de los extractos fue observado con 10% A. sativum, con inhibición significativa (P<0,01) sobre todos los hongos estudiados. El ensayo mostró el potencial de extractos crudos de A. sativum y O. gratissimum sobre hongos patógenos que afectan la yuca. Este potencial del extracto crudo de estas plantas provee una alternativa a los campesinos para el control y reducción de la pudrición de la yuca, por ser económicos, no fitotóxicos y fácil de preparar.

Seis fungos patógenos causantes de apodrecimento pos-colheita em raízes de mandioca foram investigados in vitro para estudar os efeitos fungitóxicos de Allium sativum (L) e Ocimum gratissimum (L) utilizando métodos de extração aquosa. Os fungos foram isolados cortando tecido doente na interfase entre as partes sadias e infetadas da raíz. Provas de patogenicidade mostraram que Fusarium oxysporum, F. solani, Botryodiplodia theobromae, Macrophomina phaseolina, Penicillium oxalicum e Aspergillus niger induzem apodrecimento em tubérculos sadios de mandioca depois de 8 dias de reinoculação, sendo P. oxalicum o mais virulento. Quatro concentrações de extrato foram obtidas de cada planta misturando 25, 50, 75 ou 100g con 100ml de água destilada estéril. O efeito fungitóxico dos extratos mostrou que A. sativum produziu uma inibição efetiva (25,2-56,9%) do crescimento micelial de todos os fungos ensaiados, enquanto que os extratos de O. gratissimum mostraram fraca a moderadamente efetiva inibição (0,9 a 64,5%) do crescimento micelial de todos os fungos com exceção de B. theobromae e M. phaseolina, que mostraram a menor porcentagem de inibição com ambos extratos. O efeito mais tóxico dos extratos foi observado com 10% A. sativum, com inibição significativa (P<0,01) sobre todos os fungos estudados. O ensaio mostrou o potencial de extratos crus de A. sativum e O. gratissimum sobre fungos patógenos que afetam a mandioca. Este potencial do extrato cru destas plantas provê uma alternativa aos camponeses para o controle e redução do apodrecimento da mandioca, por ser econômicos, não fitotóxicos e fácil de preparar.

The Stress-Activated Signaling (SAS) Pathways of a Human Fungal Pathogen, Cryptococcus neoformans

Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC (Protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The Ca2+/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.