Isolation of Sporothrix schenckii from potting soil

Isolated lymphadenopathy sporotrichosis-A rare presentation in adults: Case report

Here we present a case of atypical manifestation of Sporothrix schenkii infection where the patient complained solely of lymphadenopathy without any prior noticeable skin lesions. A Thai female who had been working in Malaysia presented to a healthcare facility with a three-month history of progressively larger and more painful lymphadenopathy at her right chin.

Soil samples from sporotrichosis transmission belt area: Searching for fungal species and their antagonistic activity against Sporothrix brasiliensis

Since 1998, the state of Rio de Janeiro, Brazil, has become a public health problem regarding sporotrichosis, a disease caused by Sporothrix spp. involving contact with infected cats. Efforts to isolate these species from environmental sources are not always successful. In our study, soil from residences situated in cities of Rio de Janeiro where cats with sporotrichosis live was collected and cultured an attempt to isolate Sporothrix spp. but it was not successful. However, other saprophytic fungal species were isolated from soil and identified and among them Purpureocillium lilacinum was the most frequent. From there, we decided to study the in vitro interaction of this species with S. brasiliensis, the principal agent that causes sporotrichosis in this state. The results showed that ten isolates of P. lilacinum inhibited the radial mycelial growth of S. brasiliensis with different percentage of inhibition. The interaction between them revealed the pattern described as overgrowth by antagonist. In conclusion, our data suggest that fungal species with very fast growth and capable of producing metabolites could hinder the growth of Sporothrix spp., it also opens the way for the identification of secondary metabolites with biological activity that could be tested against pathogenic fungi.

Zoonotic diseases of fish and their prevention and control

Fish and aquatic-derived zoonotic diseases have caused considerable problems in the aquaculture industry and fishery worldwide. In particular, zoonotic diseases can pose widespread threats to humans. With the world’s growing population and potential global trade of aquaculture and fish, the risk of environmental contamination and development of fish and aquatic-derived zoonoses in humans are increasing. The important causes of zoonoses include bacteria, parasites, viruses, and fungi. The zoonotic bacterial agents are divided into two main groups: Gram-positive (Mycobacteriaceae, Streptococcaceae, Erysipelothricaceae families) and Gram-negative (Aeromonadaceae, Vibrionaceae, Pseudomondaceae, Enterobacteriaceae, and Hafniaceae families). The premier parasitic agents include cestodes (tapeworm; e.g. Diphyllobothrium spp.), trematodes (fluke; e.g. Opisthorchis spp.), and nematodes (round worm; e.g. Anisakis spp.). In addition, protozoan organisms such as Cryptosporidium spp. are also considered fish-derived zoonotic pathogens. Two groups of fish-associated fungi causing basidiobolomycosis and sporotrichosis also pose a zoonotic risk for humans. The majority of the fish-derived zoonotic diseases are transmitted to humans mainly via the consumption of improperly cooked or raw fish or fish products. Therefore, the incidence of zoonotic diseases can be reduced by properly processing fish and fish products, e.g. by thermal (heat/freezing) treatment. The prevalence of zoonotic agents in fishes varies seasonally and should be regularly monitored to evaluate the prevalence of pathogens in both wild and cultured fish populations. This review focuses on the fish zoonotic agents/diseases and their control and prevention.

Ecological Determinants of Sporotrichosis Etiological Agents

Ecological determinants of sporotrichosis etiological agents remain poorly understood. For this reason, we performed explorations using local climate estimates to determine the temperature and humidity ranges of the environment where clinically relevant Sporothrix species occur and to identify what plant species are associated with them, using data collected from the published literature. We performed a literature search to identify all publications on environmental isolations of medically relevant species of Sporothrix in the PubMed, SCOPUS, and EMBASE databases. All those studies were included in the analysis where medically relevant species of Sporothrix have been isolated from soil samples, and described a specific geographical location that could be precisely georeferenced. We approximated temperature and humidity from local climate estimates, integrating geospatial data, temperature, and water vapor pressure from regions or provinces where medically relevant species of Sporothrix have been isolated from soil. Sporothrix spp. were more commonly isolated from soil of different regions or provinces of 16 countries. Most environmental isolates were identified as S. schenckii, whereas S. pallida, S. brasiliensis, S. globosa, and S. mexicana were rare. We estimate that medically relevant Sporothrix spp. grow in the soil at temperatures of 6.6 °C to 28.84 °C and 37.5% to 99.06% relative humidity. These findings indicate that sporotrichosis etiological agents grow in soil in ecological niches from soil with wide ranges of temperature and humidity, but they are also associated with a variety of plants, flowers, woody debris, reed leaves, corn stalks, leaves, and wood crumbs, potentially facilitating its establishment and proliferation in the environment.

The Interaction of Human Pathogenic Fungi With C-Type Lectin Receptors

Fungi, usually present as commensals, are a major cause of opportunistic infections in immunocompromised patients. Such infections, if not diagnosed or treated properly, can prove fatal. However, in most cases healthy individuals are able to avert the fungal attacks by mounting proper antifungal immune responses. Among the pattern recognition receptors (PRRs), C-type lectin receptors (CLRs) are the major players in antifungal immunity. CLRs can recognize carbohydrate ligands, such as β-glucans and mannans, which are mainly found on fungal cell surfaces. They induce proinflammatory immune reactions, including phagocytosis, oxidative burst, cytokine, and chemokine production from innate effector cells, as well as activation of adaptive immunity via Th17 responses. CLRs such as Dectin-1, Dectin-2, Mincle, mannose receptor (MR), and DC-SIGN can recognize many disease-causing fungi and also collaborate with each other as well as other PRRs in mounting a fungi-specific immune response. Mutations in these receptors affect the host response and have been linked to a higher risk in contracting fungal infections. This review focuses on how CLRs on various immune cells orchestrate the antifungal response and on the contribution of single nucleotide polymorphisms in these receptors toward the risk of developing such infections.

Sporothrix schenckii and Sporotrichosis

Sporotrichosis, which is caused by the dimorphic fungus Sporothrix schenckii, is currently distributed throughout the world, especially in tropical and subtropical zones. Infection generally occurs by traumatic inoculation of soil, plants, and organic matter contaminated with the fungus. Certain leisure and occupational activities, such as floriculture, agriculture, mining, and wood exploitation, are traditionally associated with the mycosis. Zoonotic transmission has been described in isolated cases or in small outbreaks. Since the end of the 1990s there has been an epidemic of sporotrichosis associated with transmission by cats in Rio de Janeiro, Brazil. More than 2,000 human cases and 3,000 animal cases have been reported. In humans, the lesions are usually restricted to the skin, subcutaneous cellular tissue, and adjacent lymphatic vessels. In cats, the disease can evolve with severe clinical manifestations and frequent systemic involvement. The gold standard for sporotrichosis diagnosis is culture. However, serological, histopathological, and molecular approaches have been recently adopted as auxiliary tools for the diagnosis of this mycotic infection. The first-choice treatment for both humans and cats is itraconazole.

Evaluation of pathogenic fungi occurrence in traumatogenic structures of freshwater fish

INTRODUCTION: Fungal infections in human skin, such as sporotrichosis, can occur after fish induced trauma. This work aimed to identify fungi in freshwater fish that are pathogenic to humans. METHODS: Extraction of dental arches from Serrassalmus maculatus (piranha) and Hoplias malabaricus (wolf fish), stings from Pimelodus maculatus (mandis catfish), dorsal fin rays from Plagioscion spp. (corvina) and Tilapia spp., for culture in Mycosel agar. Some cultures were submitted to DNA extraction for molecular identification by sequencing ITS-5.8S rDNA. RESULTS: Cultures identified most yeast as Candida spp., while sequencing also permitted the identification of Phoma spp. and Yarrowia lipolytica. CONCLUSIONS: While the search for S. schenckii was negative, the presence of fungus of the genera Phoma and Candida revealed the pathogenic potential of this infection route. The genus Phoma is involved in certain forms of phaeohyphomycosis, a subcutaneous mycosis caused by dematiaceous fungi, with reports of infections in human organs and systems. Traumatizing structures of some freshwater fish present pathogenic fungi and this may be an important infection route that must be considered in some regions of Brazil, since there are a large number of a fisherman in constant contact with traumatogenic fish.

Sporotrichosis in Himachal Pradesh (north India)

Sporotrichosis is being increasingly reported from a particular area of Himachal Pradesh, a state in north-west India. A skin-test survey was conducted using sporotrichin and peptido-rhamnomannan antigen among the population in the villages where 2 or more cases of sporotrichosis had been reported and results were compared with those for villages of the same where no case of sporotrichosis had been reported. The study was helped by local doctors, leaders and patients who were cured of sporotrichosis. The delayed-hypersensitivity positivity rates were significantly higher in case villages (range 22.9-40.0%) compared to control area (range 6.5-7.6%). Analysis by age showed that positivity rate increased with increase in age for both sexes. Analysis by occupation showed higher skin-test positivity in populations engaged in horticulture, nursery work, gardening, woodwork (43.2%) and farming (33.9%). The case villages have lower temperature and higher rainfall than the control villages. During the 1-year study period (1996-97), 25 cases of sporotrichosis were diagnosed: 16 cases were referred by doctors from the local area and 9 were from cases suspected during the skin-test survey. This study identifies Kangra district and adjoining areas in Himachal Pradesh as an endemic region for sporotrichosis and highlights the need for evaluation of geo-climatically similar areas.

Foodborne Sporothrix schenckii: infectivity for mice by intraperitoneal and intragastric inoculation with conidia

Experimental infections with a foodborne isolate of the fungus Sporothrix schenckii were administered to mice by intraperitoneal or intragastric injection and gavage. All injected mice showed evidence of systemic sporotrichosis. Granulomas were observed from day 3 to day 12 in the organs of neonates inoculated by injection; in mice infected by gavage, granulomas were observed only in those inoculated with 10(7) conidia. Susceptibility (based on cultural recovery) of the neonates to infections with 6 X 10(6) conidia of the fungus was 100% with intragastric injection, 91% with intraperitoneal injection, and 21 and 24% (2 X 10(7) conidia) with oral intubation. With both intragastric (59%) and intraperitoneal (25%) injections, more neonates died or were cannibalized by the mother than with intubation (14.5%). S. schenckii infected neonatal mice and caused illness by the oral route as well as by injection into the tissues or stomach. Adult mice, however, were susceptible to S. schenckii only by injection into the tissues, but not by gavage.