Biodiversity of species of Aspergillus section Fumigati in semi-desert soils in Argentina.

The distribution of Aspergillus species in soil has been widely studied all over the world. The aim of this study was the phenotypic and genotypic characterization of species Aspergillus belonging to section Fumigati present in soils from two Argentinian semi-desert areas having different geological conditions. Altogether, 23 isolates belonging to Aspergillus section Fumigati were recovered and identified using a polyphasic approach including phenotypic and molecular identifications. Aspergillus fumigatus sensu stricto and Aspergillus fumigatiaffinis had the highest frequency, of occurrence while isolates closely related to Aspergillus udagawae and Aspergillus felis were rarely observed. A. fumigatiaffinis and isolates closer to A. udagawae were isolated for the first time from Argentinian soils and this is the first report on the occurrence of species belonging to the A. felis clade in South America. Recent scientific interests in biodiversity, as well as the increasing importance of aspergilli as causative agents of human and animal diseases increase the need to understand the diversity and occurrence of these fungi in nature.

Aspergillus terreus complex: an emergent opportunistic agent of Onychomycosis.

The incidence of onychomycosis due to non-dermatophyte moulds (NDM) is increasing. Aspergillus terreus is relatively undocumented as an agent of this fungal infection. The aim of this work is to show the prevalence of onychomycosis caused by A. terreus and to describe its clinical features. Nail samples were collected for microscopic examination and culturing in selective media. All cases of onychomycosis due to NDM were confirmed by a second sample. Aspergillus terreus isolates were identified through their morphological characteristics and using molecular methods. A total of 2485 samples were obtained. Positive cultures were obtained in 1639 samples. From 124 NDM confirmed cultures, 23 were identified as A. terreus (18.5%). Superficial white onychomycosis was the most frequent clinical pattern. A high percentage was found in fingernails. The prevalence of A. terreus in this study considerably exceeded the percentages reported by other authors. Onychomycosis due to A. terreus presents similar clinical patterns to those caused by dermatophytes, but is difficult to eradicate and is associated with less predictable treatment outcomes. Better knowledge of the aetiology of A. terreus may be important for accomplishing more accurate and effective treatment.

Prevalence of Malassezia species in pityriasis versicolor lesions in northeast Argentina.

BACKGROUND: Malassezia species normally colonize the skin but they can change their saprophytic state and invade the stratum corneum as pathogens. AIMS: To determine the prevalence of Malassezia species isolated from patients with pityriasis versicolor (PV) and to analyse their distribution according to the location of the lesion on the body. METHODS: This study included 218 patients with PV and positive Malassezia cultures who resided in the city of Resistencia, a subtropical area located in northeast Argentina. Age, gender, and the body site of lesions were recorded. Strains were identified by PCR-RFLP. RESULTS: Malassezia sympodialis (37.7%) and Malassezia globosa (37.2%) were the most prevalent species isolated alone or in association with other Malassezia species in 82% of the patients. Malassezia furfur (21.3%) was the third most common species, followed by Malassezia slooffiae (1.7%), and Malassezia restricta (1.3%), which was found only in combination with M. globosa and M. sympodialis. Malassezia dermatis (0.4%) and Malassezia pachydermatis (0.4%) were each isolated once. None of the species affected a body site with statistical significance. Significant difference between genders according to age was found only in the 31-40-year-age group. CONCLUSIONS: This study suggests that M. sympodialis and M. globosa represent the main species implicated in the pathogenicity of PV. M. furfur appears to be the third agent of importance in this geographical area. Statistical analyses showed none of the species was particularly associated with any one of the body sites.

[Keratinophilic fungi in soils of parks of Corrientes city, Argentina]. / Hongos queratinofílicos en suelos de parques de la ciudad de Corrientes, Argentina.

BACKGROUND: The soil is a natural reservoir of keratinophilic fungi, which are a small but important group of filamentous fungi, some of which typically develop on keratinized tissues of living animals. There are numerous species of saprophytic fungi with recognized keratinophilic abilities, and several studies have been undertaken in order to link their presence to possible human disease. AIMS: To know the biota of geophilic fungi in general and of keratinophilic fungi particularly in soils from two public parks. METHODS: Soil samples from two public parks of Corrientes city, Argentina, were studied during two seasons, using the hook technique and serial dilutions for fungal isolation. RESULTS: Using the hook technique, 170 isolates were classified into 17 genera and 21 species, among which it is worth mentioning the presence of Microsporum canis. Shannon index for keratinophilic fungi in autumn was 2.27, and 1.92 in spring. By means of the serial dilutions technique, 278 fungi isolated were identified into 33 genera and 71 species. Shannon index in autumn was 3.9, and 3.5 in spring. CONCLUSIONS: The soils studied have particularly favorable conditions for the survival of pathogens and opportunistic geophilic fungi for humans and animals.

[Toxocara canis eggs as bait for soil fungus in a subtropical city]. / Huevos de Toxocara canis como anzuelo para hongos geófilos en una ciudad subtropical.

BACKGROUND: The use of different isolation techniques allows the recovery of fungi based on their ability to use selective substrates. The sprinkle method is a technique for the recovery of nematophagous fungi in the soil. These fungi are natural predators of nematodes and are widely distributed in nature. AIMS: To detect possible fungi with nematophagous ability in the soil of city parks in Corrientes (Argentina). METHODS: The soil samples were taken from an area of ground between two trees and to no more than 2cm deep. The isolation was performed according to the sprinkle method with Toxocara canis eggs as bait. RESULTS: Eighteen soil samples were collected, and 6 genera and 8 species of fungi were isolated. The sprinkle method, simple and efficient, has the advantage of using a small amount of untreated soil for the isolation of fungi that can grow on the eggs of geohelminths. The genera Bipolaris, Fusarium, Purpureocillium, Curvularia, Phoma and Scytalidium were isolated in this study. CONCLUSIONS: No other studies describing the interaction between the genera Curvularia, Phoma and Scytalidium with nematode eggs have been found in the literature, thus more studies are required to determine what is their real action on these eggs.

Native trees of the Northeast Argentine: natural hosts of the Cryptococcus neoformans-Cryptococcus gattii species complex.

BACKGROUND: In Argentina, information about epidemiology and environmental distribution of Cryptococcus is scarce. The city of Resistencia borders with Brazil and Paraguay where this fungus is endemic. All these supported the need to investigate the ecology of the genus and the epidemiology of cryptococcosis in this area. AIMS: The aim was to investigate the presence of species of Cryptococcus neoformans-Cryptococcus gattii complex and their genotypes in trees of the city of Resistencia. METHODS: One hundred and five trees were sampled by swabbing technique. The isolates were identified using conventional and commercial methods and genotyped by PCR-RFLP (Restriction Fragment Length Polymorphism). RESULTS: Cryptococcus was found in 7 out of the total trees. 6 out of 7 Cryptococcus isolates were identified as C. neoformans and one as C. gattii. C. gattii was isolated from Grevillea robusta. C. neoformans strains were isolated from Tabebuia avellanedae and Peltophorum dubium. Genotyping showed that all C. neoformans belonged to the VNI type and C. gattii belonged to the VGI type. CONCLUSIONS: This represents the first study on the ecology of Cryptococcus spp. associated to trees from northeastern Argentina, and the first report describing Grevillea robusta as a host of members of this fungal genus. Another finding is the isolation of C. neoformans from Tabebuia avellanedae and Peltophorum dubium, both tree species native to northeastern Argentina.

[Prevalence of Malassezia species associated with seborrheic dermatitis lesions in patients in Argentina]. / Prevalencia de especies de Malassezia asociadas a lesiones de dermatitis seborreica en pacientes de Argentina.

BACKGROUND: Seborrheic dermatitis (SD) is considered the second most frequently dermatosis associated with the genus Malassezia but little is the knowledge about the epidemiology of this association. AIMS: To determinate the prevalence of Malassezia species associated with SD and to analyse their distribution according to the location of the lesion on the body. METHODS: This study was performed in Resistencia city, located in a subtropical area in northeast Argentina. In this study, 226 skin samples from patients with lesions compatible with SD were studied. Age, gender and body sites lesion were recorded. Strains were identified by PCR-RFLP. RESULTS: One hundred and thirty-one positive cultures were obtained. Association of 2 species was detected in 10 cases; therefore, 141 strains were isolated. Malasezzia globosa (43.3%) was the most frequent species isolated, followed by Malasezzia furfur (20.6%), Malasezzia sympodialis (17%) and Malasezzia restricta (16.3%). Three isolates of Malasezzia slooffiae (2.1%) and one of Malasezzia pachydermatis (0.7%) were obtained. Statistical significance (P<0.05) was found between M. globosa and scalp. Malasezzia restricta was isolated only in head areas. CONCLUSIONS: This study suggests M. globosa is the most related species to SD. The prevalence of other species is different from that reported by other authors. Only M. globosa and M. restricta presented a pattern of relationship with the body sites of the lesions. It is noteworthy is the isolation of the zoophylic species M. pachydermatis. The Malassezia genus ecology and the pathogenic role of its species are still under study. This work is a contribution to this knowledge.

Etiology of fungaemia and catheter colonisation in Argentinean paediatric patients.

Yeast strains obtained from blood cultures and catheters from intensive care units (ICU) and hospitalised oncology paediatrics were studied. Yeast were the first cause of catheter colonisation (51/627), and the third cause of bloodstream infection (44/6065). In catheter, the most frequent species were Candida albicans (34%), C. parapsilosis (27.7%) and C. tropicalis (15%). In blood, C. albicans (40.8%), C. parapsilosis (26.6%), C. tropicalis (15%). Malassezia furfur and Malassezia sympodialis were isolated from catheters from ICU patients. All isolates were susceptible to amphotericin B, 88.8% to itraconazole and 91.9% to fluconazole. Candida albicans and C. tropicalis strains resistant to fluconazole and itraconazol were detected. These results reveal a change in the predominant role of C. albicans as cause of candidemia in hospitalised children and the emergence of antifungal resistant species. These variations emphasise the importance of performing a permanent surveillance to observe and assess them.

Fluconazole and itraconazole resistance of yeasts isolated from the bloodstream and catheters of hospitalized pediatric patients.

BACKGROUND: In critically ill children, Candida species and other yeasts appear as an important nosocomial pathogen. The emerging fungal pathogens are usually less susceptible to azole compounds, and the management of such infections could be problematic. METHODS: 6,065 bloodstream cultures and 627 catheters from intensive care units and hospitalized oncology pediatric patients were studied. Antifungal susceptibility testing of isolates was performed according to the reference broth microdilution method describedby the National Committee for Clinical Laboratory Standards (M27-A). RESULTS: We found a low activity of fluconazole (FCZ) and itraconazole (ITZ) against Candida glabrata, C. albicans, C. tropicalis and C. haemulonii. Resistant strains to FCZ and ITZ were detected. CONCLUSION: Results reveal the emergence of antifungal-resistant species and a change in the predominant role of C. albicans as a cause of candidemia in hospitalized children.

Hongos geofílicos en la zona occidental de la región chaqueña (Argentina) / Geophilic fungi in western zone of Chaco Region, Argentina

Mediante las técnicas de Orr y de dilución, se estudiaron muestras de tierra de la zona occidental de la región chaqueña recogidas durante las estaciones de invierno y verano del año 2006. Mediante el anzuelo queratínico se aislaron 22 géneros y 25 especies fúngicas. Los Onygenales estuvieron representados con sólo 8 géneros, principalmente Chrysosporium indicum, Aphanoascus fulvescens y Myceliophthora vellerea, mientras en los no Onigenales, destacan: Paecilomyces lilacinus y Aspergillus fumigatus. En las muestras procesadas por dilución en PDA, se obtuvieron 24 géneros y 43 especies. Entre éstas, el género más frecuente y con mayor diversidad fue Aspergillus, siendo A. fumigatus la especie más representada, siguiendo en importancia los micelios hialinos y dematiáceos sin fructificar, los Penicillium del sub género Biverticillium y los Trichoderma de la sección Trichoderma. Se destaca la presencia de Corynascus verrucosus y C. setosus. Con ambas técnicas no se obtuvieron diferencias significativas respecto del número total de aislamientos entre invierno y verano.

Soil samples from the western zone of Chaco Region and collected during winter and summer of 2006 were studied by means of Orr and dilution techniques. Twenty two genera and 25 fungal species resulted with the use of the keratinic bait. Onygenales were represented by only 8 genera, mainly Chrysosporium indicum, Aphanoascus fulvescens and Myceliophtora vellerea, while Paecilomyces lilacinus and Aspergillus fumigates were present in the not Onygenales group. In samples processed by PDA dilution, 23 genera and 43 species were obtained. Among these, Aspergillus was the most frequent genus and which showed the highest diversity, being A. fumigatus the highest represented species, followed in importance by fructification-free hyaline and dematiaceous mycelia, Penicillium of the sub genus Biverticillium and Trichoderma from the Trichoderma section. The presence of Corynascus verrucosus and C. setosus is also pointed out. There were no significant differences detected under both techniques as regards the overall number of isolations within winter and summer.

Algunos microhongos geofílicos de las planicies semiáridas del noroeste de la provincia de San Luis (Argentina) / Some geophilic microfungi from Norwest semiarid plains in the province of San Luis, Argentine

Por las técnicas del anzuelo queratínico y de dilución, se estudiaron tierras de las planicies semiáridas del noroeste de la provincia de San Luis (Argentina), en invierno y verano. Con la técnica del anzuelo queratínico se aislaron 12 géneros y 15 especies fúngicas, mientras en las procesadas por dilución en PDA, 15 géneros y 29 especies. La mayoría de las detectadas con la primera técnica pertenecieron a los Onygenales (65,4 por ciento), siendo Chrysosporium indicum el de más alta frecuencia, mientras que en las diluciones, la mayoría correspondió a hongos mitospóricos (>75 por ciento), dominando los integrantes del género Aspergillus (35,8 por ciento). Con ambas técnicas la riqueza de especies fue levemente superior en verano y aún cuando la diversidad general fue baja, se aprecia la capacidad de adaptación y sobrevivencia de ciertos géneros y especies en ambientes edáficos adversos.

Soils from northwestern semiarid plains in the province of San Luis (Argentina) were examined by means of keratinic bait and dilution techniques both in winter and summer. The first technique yielded 12 genera and 15 fungal species whereas those processed in PDA dilution resulted in 15 genera and 29 species. Most fungi detected with the former technique belonged to Onygenales(65.4 percent), being Chrysosporium indicum the most frequently occurring, while in dilutions mitosporic fungi(<75 percent) showed the highest occurrence, those of the genus Aspergillus having dominance (35.8 percent). The richness of species was fairly higher with both techniquesand even though general diversity was low, the ability of certain genera and species to adapt and survive underadverse edaphic environments could be clearly seen.

Hongos endófitos en 2 plantas medicinales del nordeste argentino: I: análisis morfotaxonómico de sus comunidades foliares / Endophytic fungi in medicinal plants of northeast of Argentina: I: morphotaxonomic approach of their foliar community

Se evaluó la presencia de hongos endófitos en hojas de dos plantas medicinales, Acanthospermum australe y Pterocaulon alopecuroides, utilizadas entre otras cosas para tratar infecciones cutáneas. El muestreo se realizó en el entorno rural de dos ciudades del nordeste argentino. Los especimenes fueron recogidos por aborígenes de la zona conocedores de su distribución ambiental. Los hongos se aislaron mediante la técnica de Bisseger et al., 1994 y se identificaron empleando caracteristicas morfofisiológicas. Considerando las dos plantas, se encontraron 40 morfoespecies, donde los taxa más frecuentes en Acanthospermum australe fueron: Alternaria alternata, Aureobasidium pullulans, Fusarium oxysporum, F.solani, Myrothecium roridum, Phoma spp. y Sordaria fimícola, y en Pterocaulon alopecuroides fueron: Alternaria alternata, Aureobasidium pullulans, Cladosporium cladosporioides, Curvularia lunata, Fusarium proliferatum y Myrothecium roridum. Estos taxas considerados como generalistas (o de múltiples hospedadores), presentan según la literatura específica analizada, alta producción de metabolitos secundarios bioactivos con potenciales capacidades terapéuticas antimicrobianas.

The presence of endophytic fungi in leaves of two medicinal plants (Acanthospermum australe andPterocaulon alopecuroides) used mainly to treat skin infections, was evaluated. The sampling was performed in the rural area of two cities of northeast Argentina.The specimens were collected by the aboriginals who know the ®medicines¼. Fungi were isolated employing the Bisseger et al., 1994 technique and they were identifying by morpho fisiological characteristics. Regarding the two plant species, 40 morphospecies were found. The most frequent taxa in Acanthospermum australe were: Alternaria alternata, Aureobasidium pullulans, Fusarium oxysporum, F. solani, Myro-thecium roridum, Phoma sp. and Sordaria fimícola, and inPterocaulon alopecuroides were: Alternaria alternata, Aureobasidium pullulans, Cladosporium cladosporioides, Curvularia lunata, Fusarium proliferatum y Myrothecium roridum. These species considered generalistics (found in multiple hosts), presented in the analized literature a high production of bioactive secondary metabolites with eventual antimicrobial therapeutic properties.

Micota ambiental en la unidad de terapia intensiva de un hospital pediátrico / Ambiental mycota at an intensive care unit of a pediatric hospital

En las últimas décadas se ha demostrado claramente el rol del aire en la transmisión de microorganismos oportunistas en ambientes endógenos, especialmente en centros hospitalarios, personal dependiente y en pacientes susceptibles hospitalizados. El presente trabajo tiene como finalidad detectar la cantidad y diversidad de la micobiota anemófila y de superficies presente en la Unidad de Terapia Intensiva (UTI) del Hospital Pediátrico ®Juan Pablo II¼ de la ciudad de Corrientes (Argentina), mediante un Colector SAS súper 100 y por el método del hisopo, en 2 períodos estacionales (otoño y primavera), cada 15 días, a mediodía y después de la limpieza habitual de la unidad. El número de UFC hallado, excedió considerablemente los parámetros establecidos y los géneros de hongos filamentosos más frecuentes en el aire y en las superficies fueron los integrantes de los géneros: Cladosporium, Penicillium y Aspergillus, seguidos por Acremonium, Fusarium, Curvularia y Chrysonilia. Algunos de sus integrantes son considerados como patógenos oportunistas y productores de toxinas como: Aspergillus fumigatus, A.flavus, A.niger, Acremonium strictum complex, Fusarium oxysporum, Trichoderma harzianum y Stachybotrys atra, (este último se presentó una sola vez). La presencia de estos taxa se considera inaceptable en ambientes cerrados. Debido a la información obtenida en el presente trabajo se intensificaron las medidas para disminuir la carga fúngica ambiental de esta zona hospitalaria donde están bajo tratamiento intensivo pacientes en alto riesgo.

Lately decades have clearly evidenced the role that air plays in the transmission of opportunistic microorganisms under endogenous environments, mainly in hospitals, health centers, working personnel as well as in liable patients that are hospitalized. The present paper has been designed to detect the amount and diversity of anemophyle and surface mycota occurring at the Intensive Care Unit (UTI) in the Hospital Pediátrico ®Juan Pablo II¼ of the city of Corrientes (Argentina) by means of a super 100 SAS Colector and using the sprinkling water method in 2 seasonal periods (fall and spring), every 15 day, at midday and after the regular cleaning process of the unit. The number of UFC found exceeded greatly the established parameters whilst filamentous fungi occurring most frequently in the air and surfaces were those belonging to the genera: Cladosporium, Penicillium and Aspergillus, followed by Acremonium, Fusarium, Curvularia and Chrysonilia. Some of their members are considered opportunistic pathogenus and toxin producers such as Aspergillus umigatus, A.flavus, A.niger, Acremonium strictum complex, Fusarium oxysporum, Trichoderma harzianum and Stachybotrys atra, (the latter appeared only once). The presence of these taxa is found to be unacceptable indoors. Considering the information described in this paper, control measures were intensified to reduce environmental fungal load in this hospital area where patients under high risk are treated.

Histoplasmin and paracoccidioidin skin reactivity in infantile population of Northern Argentina

Para avaliar as idades em que os agentes etiologicos das micoses sistemicas iniciam a infeccao, testes cutaneos da histoplasmina e paracoccidioidina foram realizados em 244 criancas de ambos os sexos, com idades entre 2 e 15 anos. Foram selecionadas de amostra estatisticamente significante da populacao da cidade de General San Martin (Nordeste da Argentina). Os testes foram analisados 48 horas apos a injecao e considerados positivos se uma enduracao de 5 mm ou mais estivesse presente. Anticorpos circulantes foram tambem avaliados pela imunodifusao em gel de agar. A media de infeccao para o H. capsulatum foi de 9,2 por cento e pertencia as criancas de 4 a 14 anos, sem diferenca significante entre os sexos...

Actividad lipasa de especies de Malassezia aisladas en pacientes sanos y con lesiones dérmicas / Lipase activity of Malassezia species isolated from healthy patients and having dermic lesions

Las levaduras del género Malassezia forman parte de la micro biota normal de piel humana y animal. Excepto M. pachydermatis, todas las especies de este género son lipodependientes. Bajo ciertos factores, Malassezia se asocia como agente etiológico en diversas afecciones dérmicas. Uno de los principales factores de virulencia de estas levaduras es su actividad de lipasa (AL). El objetivo de este trabajo fue introducir modificaciones a las técnicas de determinación de la actividad lipasa (AL) para su aplicación en levaduras lipodependientes y estudiar la AL en cepas de Malassezia aisladas de personas con piel sana y de pacientes con pitiriasis versicolor (PV), dermatitis seborreica (DS) y psoriasis (PS). Se estudiaron 94 cepas aisladas de 34 pacientes con lesiones de PV, 20 con DS, 7 con PS y 33 cepas de personas con piel sana. Las modificaciones planteadas a la técnica, que incluyeron variación del medio de cultivo y tiempos de incubación, permitieron la determinación semi cuantitativa de la AL con resultados claros y definidos. El 88,23 por ciento de las cepas presentó AL. No se obtuvieron diferencias estadísticamente significativas al comparar la AL entre las cepas de pacientes con afecciones de piel y las cepas aisladas de personas sanas. La producción de lipasas de las especies de Malassezia en orden decreciente fue: M. sympodialis, M. slooffiae, M. furfur, M. globosa, M. restricta. M. globosa y M. furfur fueron las especies en que se observaron mayor cantidad de cepas no productoras de AL y cepas con gran variabilidad en la medida de AL.

Yeasts of the genus Malassezia are part of the regular microbiota in human and animal skin. Except for M. pachydermatis, all the species of this genus are lipodependent. Malassezia, under certain factors, is associated as an etiological agent in diverse dermic affections. One of the main virulence factors of these yeasts is their lipase activity (LA). The objective of this research was to introduce some changes in the techniques adopted to determine the lipase activity (LA) in order to apply them to lipodependent yeasts and to study likewise the LA in Malassezia strains isolated from healthy skin people and patients diagnosed with pitiriasis versicolor (VP), greasy dermatitis (GD) and psoriasis ( PS). Ninety four strains isolated from 34 patients having VP lesions, 20 with GD, 7 with PS and 33 strains from healthy skin people. Changes suggested to the technique involved a variation in the medium of culture as well as in the time of incubation what resulted in the semiquantitative determination of the LA together with clear and precise results. The presence of LA was observed in of 88.23 percent strains. The comparison of the LA among strains of patients bearing injured skin and those isolated from healthy skin did not show any significant statistical difference. The production of lipasae from Malassezia species were in decreasing order: M.sympodialis, M. slooffiae, M.furfur,M.globosa and M.restricta. M. globosa and M. furfur were the species that revealed the highest number of non producting LA strains as well as strains with the highest variability in the degree of LA.

Micoflora queratinofilica en suelos de la ciudad de Corrientes (Rep. Arg.) / Keratinophylic mycoflora in soil of Corrientes city (Argentine)

Se analizaron mediante la técnica del anzuelo, 116 muestras de suelos de la ciudad de Corrientes (Argentina) tomados en invierno y een verano, para aislar hongos queratinofílicos. El; estudio macromorfológico de los hongos recuperados se realizó a los 15, 30 y 45 días por medio de lupa binocular de aumentos, sembrándolos luego en medios de Sabouraud-dextrosa, Sabouraud-dextrosa-rifamicina, Mycobiotic y medio de agar papa. Se realizó también el análisis físico-químico de los suelos, determinándose pH, contenido de fósforo asimilable, nitratos, textura y materia orgánica. Los cultivos mostraros la presencia de hongos queratófilos en el 100 por ciento de las muestras, comrrespondiendo a loos géneros Trichophyton, Penicillium, Microsporum, Crysosporium, Ctenomyces y Deschlera. En algunos casos hubo aislamientos únicos pero en la mayoría fueron asociaciones de 2, 3 y hasta 4 géneros. Sin embargo Microsporum sólo apareció en el 19,8 por de las muestras. Los suelos fueron mayoritariamente alcalinos, todos arenosos y con buen contenidos de fósforo asimelable. Los resultados obtenidos revelan la existencia de condiciones particularmente favorables para el desarrollo de hongos queratófilos en los suelos de la ciudad de Corrientes

Keratinophilic fungi in soils of Corrientes city (Argentina)

Se analizaron mediante la técnica del anzuelo, 116 muestras de suelos de la ciudad de Corrientes (Argentina), para aislar hongos queratinofílicos. Los cultivos mostraron la presencia de éstos en el 100% de las muestras, correspondiendo en orden decreciente a los géneros Trichophyton, Penicillium, Microsporum, Chrysosporium, Ctenomyces y Drechslera. En algunos casos hubo aislamientos únicos, pero en la mayoría fueron asociaciones de 2, 3 y hasta 4 géneros. Se realizó también el análisis físico-químico de los suelos, determinándose pH, contenido de fósforo asimilable, nitratos, textura y materia orgánica. Los suelos fueron mayoritariamente alcalinos, todos arenosos y con buen contenido de fósforo asimilable. Los resultados obtenidos revelan la existencia de condiciones particularmente favorables para el desarrollo de hongos queratinofílicos en los suelos de la ciudad de Corrientes

Distribución altitudinal de hongos queratinofilos, epífitos y endófitos en suelos semiáridos del noreste argentino (Prov. de Jujuy, 23°L. S y 66°L. W) / Altitudinal distribution of keratinophilic, epiphytic and endophytic fungi from northwestern argentinian semiarid soils (Prov. of Jujuy, 23°L. S and 66°L. W)

En zonas semidesérticas del noreste argentino, entre los 200 y 3700m de altura y en época veraniega, se colectaron mediante anzuelo queratínico y vegetal (epífitos y endófitos), 26 muestras de suelos y 41 de flora autóctona, obteniéndose un total de 555 aislamientos fúngicos repartidos en 60 géneros y 100 especies. Los géneros con mayor número de especies correspondieron a: Acremonium, Aspergillus, Chaetomium, Fusarium, Phoma y Ulocladium. En las 3 metodologías y entre los 2000 y 3000m, se obtuvo el mayor número de taxa y los mayores aislamientos en todas las altitudes, correspondieron a los epífitos y a los endófitos, donde los Hyphomycetes constituyeron el grupo más representativo en géneros y especies. Los Onygenales fueron poco representados en el sustrato queratínico, y la mayor presencia correspondió a Chrysosporium keratinophilum, Gymnascella aurantiaca y Aphanoascus fulvescens, mientras en otros grupos taxonómicos, la especie más frecuente fue Paecilomyces lilacinus. Debe destacarse la capacidad de este substrato para detectar la presencia de Fonsecaea pedrosoi un importante agente de cromoblastomicosis en Argentina. En los epífitos, el 41,8 porciento de los aislamientos fueron representados por: Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Penicillium spp. y Ulocladium atrum complex. En los endófitos, los integrantes de los géneros Chaetomium, Aspergillus, Phoma y Fusarium, presentaron la mayor diversidad de especies bajo los 3000m, a mayor altitud, sólo Phoma mantuvo una alta diversidad. A.alternata complex, fue la especie con mayor capacidad adaptativa en las 3 metodologías y en las 2 altitudes. En el área estudiada, la altitud parece no afectar la diversidad de especies sobre los substratos analizados, donde la flora autóctona de la región, más que el suelo, parece representar el reservorio y hábitat más propicio.

Microhongos anemofilos en ambientes abiertos de dos ciudades del nordeste argentino / Anemophilous microfungi in outdoor environments of two cities

Con el objetico de estudiar los mirohongos anÚmofilos de las ciudades de Resistencia y Corrientes, ubicadas en el nordeste argentino, se muestrearon por la tÚcnica de depòsitación gravitacional, dos zonas en cada ciudad. El muestreo se realizó en primavera y otoño, en dos horarios diferentes. Existe diferencvia entre los aislamientos de ambas ciudades. En Resistencia se observó un mayor número de taxa (323) que enn Corrientes, (248) siendo mßs notoria esta diferencia en otoño junto a una mayor diversidad de gÚneros (34/28). Los gÚneros mßs frecuentes en ambas ciudades fueron: Cladosporium, Aspergillus, Penicillium, Phona, Fusarium , Alternaria, Curvularia y Trichoderma. Un buen número de los hongos aislados son de interÚs en salud publica por sus capacidades oportunistas en diversos cuadros clinicos, asi comno en alergias o micotoxocosis.