Water Quality, Heavy Metals, and Antifungal Susceptibility to Fluconazole of Yeasts from Water Systems.

Aquatic environments could be reservoirs of pathogenic yeasts with acquired antifungal resistance. The susceptibility to antifungal agents of yeasts present in the wastewater and natural waters of the city of Cali was evaluated. Samples were taken from two types of water: drinking water (Meléndez River, drinking water treatment plant "Puerto Mallarino" in the Cauca River) and wastewater (South Channel of the Cauca River, "Cañaveralejo-PTAR" wastewater treatment plant). Physico-chemical parameters, heavy metal concentration, and yeast levels were determined using standard procedures. Yeasts were identified using API 20 C AUX (BioMérieux) and sequence analysis of the ITS1-5.8S-ITS2 and D1/D2 regions of the large subunit of the ribosome. Susceptibility assays against fluconazole and amphotericin B using the minimum inhibitory concentration (MIC) test were determined using the microdilution method. The influence of physico-chemical parameters and heavy metals was established using principal component analysis (PCA). Yeast counts were higher at WWTP "PTAR" and lower at Melendez River, as expected. A total of 14 genera and 21 yeast species was identified, and the genus Candida was present at all locations. Susceptibility tests showed a 32.7% resistance profile to fluconazole in the order DWTP "Puerto Mallarino = WWTP "PTAR" > South Channel "Navarro". There were significant differences (p < 0.05) in the physico-chemical parameters/concentration of heavy metals and yeast levels between the aquatic systems under study. A positive association was observed between yeast levels and total dissolved solids, nitrate levels, and Cr at the "PTAR" WWTP; conductivity, Zn, and Cu in the South Channel; and the presence of Pb in the "Puerto Mallarino" DWTP. Rhodotorula mucilaginosa, Candida albicans, and Candida sp. 1 were influenced by Cr and Cd, and Diutina catelunata was influenced by Fe (p < 0.05). The water systems explored in this study showed different yeast levels and susceptibility profiles, and, therefore, possible genetic differences among populations of the same species, and different physico-chemical and heavy metals concentrations, which were probably modulating the antifungal-resistant yeasts. All these aquatic systems discharge their content into the Cauca River. We highlight the importance to further investigate if these resistant communities continue to other locations in the second largest river of Colombia and to determine the risk posed to humans and animals.

Study of Titanium-Silver Monolayer and Multilayer Films for Protective Applications in Biomedical Devices.

The search for coatings that extend the useful life of biomedical devices has been of great interest, and titanium has been of great relevance due to its innocuousness and low reactivity. This study contributes to the investigation of Ti/Ag films in different configurations (monolayer and multilayer) deposited by magnetron sputtering. The sessile droplet technique was applied to study wettability; greater film penetrability was obtained when Ag is the external layer, conferring high efficiency in cell adhesion. The morphological properties were characterized by SEM, which showed porous nuclei on the surface in the Ag coating and crystals embedded in the Ti film. The structural properties were studied by XRD, revealing the presence of TiO2 in the anatase crystalline phase in a proportion of 49.9% and the formation of a silver cubic network centered on the faces. Tafel polarization curves demonstrated improvements in the corrosion current densities of Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti and Ti/Ag compared to the Ag coating, with values of 0.1749, 0.4802, and 2.044 nA.m-2, respectively. Antimicrobial activity was evaluated against the bacteria Pseudomonas aeruginosa and Bacillus subtilis and the yeasts Candida krusei and Candida albicans, revealing that the Ti/Ag and Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti coatings exhibit promise in biomedical material applications.

Structure of Bacterial Community with Resistance to Antibiotics in Aquatic Environments. A Systematic Review.

Aquatic environments have been affected by the increase in bacterial resistant to antibiotics. The aim of this review is to describe the studies carried out in relation to the bacterial population structure and antibiotic resistance genes in natural and artificial water systems. We performed a systematic review based on the PRISMA guideline (preferred reporting items for systematic reviews and meta-analyzes). Articles were collected from scientific databases between January 2010 and December 2020. Sixty-eight papers meeting the inclusion criteria, i.e., "reporting the water bacterial community composition", "resistance to antibiotics", and "antibiotic resistance genes (ARG)", were evaluated according to pre-defined validity criteria. The results indicate that the predominant phyla were Firmicutes and Bacteroidetes in natural and artificial water systems. Gram-negative bacteria of the family Enterobacteraceae with resistance to antibiotics are commonly reported in drinking water and in natural water systems. The ARGs mainly reported were those that confer resistance to ß-lactam antibiotics, aminoglycosides, fluoroquinolones, macrolides and tetracycline. The high influence of anthropogenic activity in the environment is evidenced. The antibiotic resistance genes that are mainly reported in the urban areas of the world are those that confer resistance to the antibiotics that are most used in clinical practice, which constitutes a problem for human and animal health.

Crecimiento del complejo Cryptococcus neoformans/ Cryptococcus gattiien extractos de excretas de palomas / Growth of Cryptococcus neoformans/Cryptococcus gattii species complex in pigeon excreta / Crescimento do complexo Cryptococcus neoformans/ Cryptococcus gattii em extratos de excrementos de pombos

RESUMEN Cryptococcus neoformans/Cryptococcus gattii son agentes etiológicos de la criptococosis, el primero tiene distribución mundial y su hábitat principal son las excretas de palomas (Columba livia), mientras que el último se ha aislado de árboles y en pocas ocasiones de heces de aves. En este estudio se comparó en condiciones de laboratorio, el crecimiento de C. neoformans y C. gattii en extractos de excretas de paloma. Se utilizaron dos extractos de heces de aves cautivas: uno de una muestra en la que se aisló C. neoformans (extracto positivo) y otro de una muestra negativa para este hongo (extracto negativo), los cuales fueron inoculados con C. neoformans y C. gattii. Los extractos permitieron el desarrollo de las dos especies y, mostraron un patrón de crecimiento uniforme en el extracto negativo, mientras que, en el positivo, el crecimiento de C. neoformans fue mayor comparado con el de C. gattii (P = 0.0001). El crecimiento de C. gattii fue menor a un pH superior a 7,5, mientras que el crecimiento de C. neoformans no mostró diferencias significativas en los dos extractos independiente de las variaciones del pH. Se necesitan más estudios para elucidar la interacción de estas dos especies en las excretas de palomas.

ABSTRACT Cryptococcus neoformans/Cryptococcus gattii are etiologic agents of cryptococcosis, the former has a worldwide distribution, and its habitat is associated with pigeon excreta (Columba livia), whereas the latter it has been mainly associated with trees and rarely from the feces of birds. In this study was to compare, under laboratory conditions, the growth of C. neoformans and C. gattii in extracts of pigeon excreta. Two extracts of captive bird feces were used: one prepared from a sample in which C. neoformans was isolated (positive extract) and one from which sample was negative for this fungus (negative extract). Under laboratory conditions, the extracts allowed the development of both species. Both showed a uniform pattern of growth in the negative extract, whereas in the positive, C. neoformans growth was significantly higher than that of C. gattii (P = 0.0001). The growth of the C. gattii was lower in positive extracts and it seems to decrease at pH greater than 7.5, whereas the growth of C. neoformans showed no significant differences regardless of pH variations. Further studies are need to elucidate the interaction between these two species in the excreta of pigeon.

RESUMO Cryptococcus neoformans / Cryptococcus gattii são agentes etiológicos da criptococose, o primeiro tem distribuição mundial e seu habitat principal é a excreção de pombos (Columba livia), enquanto o último foi isolado de árvores e raramente de fezes de aves. Neste estudo, o crescimento de C. neoformans e C. gattii nos extratos de excrementos de pombo foi comparado em condições de laboratório. Foram utilizados dois extratos de fezes de aves em cativeiro: um de uma amostra em que C. neoformans (extrato positivo) foi isolado e outro de uma amostra negativa para esse fungo (extrato negativo), que foi inoculado com C. neoformans e C gattii Os extratos permitiram o desenvolvimento das duas espécies e mostraram um padrão de crescimento uniforme no extrato negativo, enquanto no positivo o crescimento de C. neoformans foi maior em comparação ao de C. gattii (P = 0,0001). O crescimento de C. gattii foi menor a pH maior que 7,5, enquanto o crescimento de C. neoformans não mostrou diferenças significativas nos dois extratos, independentemente das variações de pH. Mais estudos são necessários para elucidar a interação dessas duas espécies nos excrementos de pombos.

Capacidad solubilizadora de fosfato de aluminio por hongos rizosféricos aislados de un Andisol colombiano / Solubilizing capacity of aluminum phosphate by rhizospheric fungi isolated from an Andisol Colombian / Capacidade de solubilização de fosfato de alumínio por fungos rizosféricos isolados de um Andisol colombiano

RESUMEN A partir de un Typic Melanudands cultivado con café (Coffea arabica variedad Caturra), proveniente del Departamento del Cauca (Colombia), se aislaron hongos con capacidad solubilizadora de fosfato de aluminio (Al-P), de los cuales se seleccionaron dos microorganismos que presentaron la mayor actividad, identificados como cepa UNHI (Mycelia sterilia), y UNH2 (Penicillium sp). Los hongos seleccionados fueron evaluados por quince días en medio líquido Pikovskaya (PVK) con Al-P bajo dos condiciones, con agitación (método A) y en reposo con aireación (método B). Al comparar los resultados se encontraron diferencias estadísticas significativas en el porcentaje de fósforo soluble, el método A presentó mejores resultados con un porcentaje de 73,8% frente a 62% con la cepa UNH1 y en menor proporción con la cepa UNH2 49% y 44%. El incremento de biomasa fue mayor con el método B y el pH de los medios de cultivo no mostraron diferencias significativas, con un pH promedio de 2,7.

ABSTRACT Based on Typic Melanudands grow with coffea (Coffea Arabica Caturra variety) resulting from the Cauca department, fungi with solubilization capacity of aluminum phosphate were isolated (Al-P), from which two microorganisms with greater solubilization activity were selected, identified as strain UNH!: Mycelia sterilia y UNH2: Penicillium sp. Selected fungi were evaluated through the Pikovskaya liquid (PVK) with (Al-P), under two conditions, with stirring (A method) and repose with aireation ( B method), for fifteen days. When comparing the results, significant statistical differences were found in the percentage of soluble phosphorus, method A presented better results with a percentage of 73.8% compared to 62% with the strain UNH1 and in smaller proportion with the strain UNH2 49% and 44 %. The increase in biomass was greater with method B and the pH of the culture media did not show significant differences, with an average pH of 2.7.

RESUMO De PVAc Melanudands cultivadas com café (Coffea arabica variedade caturra), a partir do Departamento (Colômbia), fungos foram isoladas com fosfato de alumínio capacidade de solubilização (Al-P), de que introduziu foram seleccionados dois microrganismos a atividade mais alta, identificada como cepa UNH1 (Mycelia sterilia) e UNH2 (Penicillium sp). fungos seleccionados foram avaliadas durante duas semanas em meio líquido Pikovskaya (PVK) com Al-P sob duas condições, com agitação (método A) e que descansa com arejamento (método B). Ao comparar os resultados estatisticamente diferenças significativas na percentagem de fósforo solúvel encontrada, método A proporcionou melhores resultados com uma percentagem de 73,8% versus 62% com a estirpe UNH1 e em menor grau com a estirpe UNH2 49% e 44 %. O aumento da biomassa foi maior com o método B e o pH do meio de cultura não mostrou diferenças significativas, com um pH médio de 2,7.