Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14755

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Mostrando 1 - 7 de 7

A case study on pharmaceutical residues and antimicrobial resistance genes in Costa Rican rivers : a possible route of contamination for feline and other species
(Elsevier, 2023-11-12) Vargas-Villalobos, Seiling; Hernández, Felix; Fabregat-Safont, David; Salas-González, Denis; Quesada-Alvarado, Francisco; Botero-Coy, Ana Maria; Esperón, Fernando; Martín-Maldonado, Bárbara; Monrós-González, Juan; Ruepert, Clemens; Estrada-König, Sandra; Rivera-Castillo, Josué; Chaverri-Fonseca, Fabio; Blanco-Peña, Kinndle
In this investigation, the presence of antibiotics and pharmaceuticals in Costa Rican surface waters, specifically in regions near feline habitats, was examined. The study revealed that 47% of the water samples contained detectable traces of at least one antibiotic. Ciprofloxacin and norfloxacin were the most frequently detected compounds, each with a detection rate of 27%. Other antibiotics, such as erythromycin, roxithromycin, and trimethoprim, were also found but at lower frequencies, around 14%. Notably, all antibiotic concentrations remained below 10 ng/L, with ciprofloxacin, norfloxacin, and erythromycin showing the highest concentrations. Furthermore, the investigation revealed the presence of non-antibiotic pharmaceutical residues in the water samples, typically at concentrations below 64 ng/L. Tramadol was the most frequently detected compound, present in 18% of the samples. The highest concentrations were observed for acetaminophen and tramadol, measuring 64 and 10 ng/L, respectively. Comparing these findings with studies conducted in treated wastewater and urban rivers, it became evident that the concentrations of antibiotics and pharmaceuticals were notably lower in this study. While previous research reported higher values, the limited number of studies conducted in protected areas raises concerns about the potential environmental impact on biodiversity. In summary, these results emphasize the importance of monitoring pharmaceutical residues and antimicrobial resistance genes ARGs in vulnerable ecosystems, especially those in close proximity to feline habitats in Costa Rica. Additionally, the study delved into the detection of (ARGs). All tested water samples were positive for at least one ARG, with the blaTEM gene being the most prevalent at 82%, followed by tetS at 64% and qnrB at 23%. Moreover, this research shed light on the complexity of evaluating ARGs in environmental samples, as their presence does not necessarily indicate their expression. It also highlighted the potential for co-selection and coregulation of ARGs, showcasing the intricate behaviors of these genes in aquatic environments.
Anthropogenic imprint on riverine plasmidome diversity and proliferation of antibiotic resistance genes following pollution and urbanization
(Universidad Nacional, Costa Rica, 2025-03-24) Barrantes-Jiménez, Kenia ; Lejzerowicz, Franck; Tran, Tam; Calderón-Osorno, Melany; Rivera-Montero, Luis; Rodríguez-Sánchez, César; Wikmark, Odd-Gunnar; Eiler, Alexander; Grossart, Hans-Peter; Arias-Andrés, María; Rojas-Jiménez, Keilor
Plasmids are key determinants in microbial ecology and evolution, facilitating the dissemination of adaptive traits and antibiotic resistance genes (ARGs). Although the molecular mechanisms governing plasmid replication, maintenance, and transfer have been extensively studied, the specific impacts of urbanization-induced pollution on plasmid ecology, diversity, and associated ARGs in tropical regions remain underexplored. This study investigates these dynamics in a tropical aquatic ecosystem, providing novel insights into how pollution shapes plasmid composition and function. In contrast to the observed decrease in chromosomal diversity, we demonstrate that pollution associated with urbanization increases the diversity and taxonomic composition of plasmids within a bacterial community (plasmidome). We analyzed eighteen water and sediment metagenomes, capturing a gradient of pollution and ARG contamination along a tropical urban river. Plasmid and chromosomal diversity profiles were found to be anti-correlated. Plasmid species enrichment along the pollution gradient led to significant compositional differences in water samples, where differentially abundant species suggest plasmid maintenance within specific taxonomic classes. Additionally, the diversity and abundance of ARGs related to the plasmidome increased concomitantly with the intensity of fecal and chemical pollution. These findings highlight the critical need for targeted plasmidome studies to better understand plasmids' environmental spread, as their dynamics are independent of chromosomal patterns. This research is crucial for understanding the consequences of bacterial evolution, particularly in the context of environmental and public health.
Associations between pesticide mixtures applied near home during pregnancy and early childhood with adolescent behavioral and emotional problems in the CHAMACOS study
(ENVIRONMENTAL EPIDEMIOLOGY, 2021) Hyland, Carly; Bradshaw, Patrick T.; Gunier, Robert; Mora, Ana M.; Kogut, Katherine; Deardorff, Julianna; Sagiv, Sharon; Bradman, Asa; Eskenazi, Brenda
Evidence from longitudinal cohort studies indicates that biomarkers of pesticide exposure and residential proximity to agricultural pesticide applications during pregnancy and early childhood may be associated with adverse child neurodevelopment, including poorer cognition1–6 and increased hyperactivity/ inattention7–9 and traits related to autism spectrum disorders.10–13 Despite relatively consistent findings for outcomes assessed during early and middle childhood, previous studies have only followed children up to the age of 12 years, and data gaps exist regarding the persistence of pesticide–neurodevelopment associations into adolescence and young adulthood.
Effects of the insecticide β-endosulfan on tadpoles of Isthmohyla pseudopuma (Anura: Hylidae)
(Elsevier, 2022) Méndez Rivera, Michael.; Mena, Freylan; Pinnock Branford, Margaret; Ruepert, Clemens; Barquero, Marco D.; Jiménez, Randall R.; Alvarado, Gilbert
Conventional agriculture uses pesticides intensively. Once pesticides are released into the environment, they can be toxic to non-target organisms. Exposure of amphibians to pesticides can be lethal and affect their growth, development and behavior. β-endosulfan is a persistent organochlorine that has been detected in environmental samples within protected sites in Costa Rica, far from agricultural areas. The aim of this study was to evaluate the lethal and sublethal effects, as well as changes in three biomarkers (Cholinesterase activity [ChE], glutathione S- transferase activity [GST] and lipid peroxidation [LPO]) in tadpoles of Isthmohyla pseudopuma exposed to β-endosulfan. A 96-h acute test (20, 40, 60, 80, 100 and 200 µg/L) was performed in order to calculate the median lethal concentration (LC 50 ), while effects on growth and development were assessed during a 4-weeks chronic test (10, 20, 30 and 50 µg/L). In addition, we measured the aforementioned biomarkers in tadpoles exposed to concentrations below the LC 50 . The 96-h LC 50 for this species was 123.6 µg/L. We found no evidence of β-endosulfan influencing any of the three biomarkers evaluated. At 50 µg/L, both length and total weight of tadpoles decreased with respect to the control. Also, at 30 and 50 µg/L we observed that individuals showed a slower development. Therefore, we demonstrated that at sublethal concentrations, β-endosulfan negatively affects I. pseudopuma at early stages causing tadpoles to develop slower and smaller than normal.
Short-term exposure to benzalkonium chloride in bacteria from activated sludge alters the community diversity and the antibiotic resistance profile
(IWA PUBLISHING, 2021) Chacón, Luz.; Arias-Andrés, Maria; Mena, Freylan; Rivera, Luis.; Hernández, Lorena; Achi, Rosario; Garcia, Fernando.; Rojas-Jiménez, Keilor.
La introducción continua de productos de limpieza que contienen cloruro de benzalconio (BAC) procedente de vertidos domésticos puede moldear las comunidades microbianas de las plantas de tratamiento de aguas residuales (EDAR) de una forma aún poco conocida. En este estudio, realizamos una exposición in vitro de lodos activados de una EDAR de Costa Rica a BAC, cuantificamos los cambios en los perfiles génicos intI1, sul2 y qacE/qacEΔ1, y determinamos alteraciones en la composición de la comunidad bacteriana. El análisis de los datos de qPCR reveló elevadas cargas de genes de resistencia a antibióticos en la comunidad microbiana; tras la exposición a BAC se observó un aumento significativo del gen qacE/qacEΔ1, relacionado con la resistencia al cuaternario de amonio. El análisis de las secuencias del gen 16S rRNA mostró variaciones pronunciadas en la estructura de las comunidades bacterianas, incluyendo una reducción de los valores de diversidad alfa y un aumento de la abundancia relativa de Alphaproteobacteria, particularmente de Rhodospseudomonas y Rhodobacter. Confirmamos que las comunidades microbianas presentaban una alta resiliencia al BAC en la concentración de mg/mL, probablemente debido a la exposición constante a este contaminante. También presentaron genes relacionados con la resistencia a antibióticos con mecanismos similares para tolerar esta sustancia. Estos mecanismos deberían explorarse más a fondo, especialmente en el contexto de un elevado uso de desinfectante.
The fungicide chlorothalonil changes the amphibian skin microbiome: a potential factor disrupting a host disease-protective trait
(MDPI, 2021-04-08) Jiménez, Randall R.; Alvarado, Gilbert; Ruepert, Clemens; Ballestero, Erick.; Sommer, Simone
The skin microbiome is an important part of amphibian immune defenses and protects against pathogens such as the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis. Alteration of the microbiome by anthropogenic factors, like pesticides, can impact this protective trait, disrupting its functionality. Chlorothalonil is a widely used fungicide that has been recognized as having an impact on amphibians, but so far, no studies have investigated its effects on amphibian microbial communities. In the present study, we used the amphibian Lithobates vibicarius from the montane forest of Costa Rica, which now appears to persist despite ongoing Bd-exposure, as an experimental model organism. We used 16S rRNA amplicon sequencing to investigate the effect of chlorothalonil on tadpoles’ skin microbiome. We found that exposure to chlorothalonil changes bacterial community composition, with more significant changes at a higher concentration. We also found that a larger number of bacteria were reduced on tadpoles’ skin when exposed to the higher concentration of chlorothalonil. We detected four presumed Bd-inhibitory bacteria being suppressed on tadpoles exposed to the fungicide. Our results suggest that exposure to a widely used fungicide could be impacting host-associated bacterial communities, potentially disrupting an amphibian protective trait against pathogens.
The Impact of Urban Pollution on Plasmid-Mediated Resistance Acquisition in Enterobacteria from a Tropical River
(Universidad Nacional, Costa Rica, 2024-11-14) Mendoza Guido, Bradd; Arias Andres, Maria; Barrantes, Kenia; Rodrıguez, Cesar; Rojas-Jimenez, Keilor
The exposure of environmental bacteria to contaminants in aquatic ecosystems accelerates the dissemination of antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). In this study, we sampled three locations along a contamination gradient of a polluted river, focusing on isolating Enterobacteria from the surface waters to investigate the relationship between urban pollution and antibiotic resistance. The genomes of 15 isolates (5 per site) were sequenced to identify plasmid-borne ARGs and their association with resistance phenotypes. Results: Isolates from the site with the highest contamination (Site 3) showeda larger number of ARGs, plasmids, and resistance phenotypes. Notably, one of the isolates analyzed, E. coli A231-12, exhibited phenotypic resistance to seven antibiotics, presumably conferred by a single plasmid carrying 12 ARGs. Comparative analysis of this plasmid revealed its close evolutionary relationship with another IncH plasmid hosted by Salmonella enterica, underscoring its high ARG burden in the aquatic environment. Other plasmids identified in our isolates carried sul and dfrA genes, conferring resistance to trimethoprim/sulfamethoxazole, a commonly prescribed antibiotic combination in clinical settings. These results highlight the critical need to expand research on the link between pollution and plasmid-mediated antimicrobial resistance in aquatic ecosystems, which can act as reservoirs of ARGs.

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