Examinando por Autor "Araos, Rafael"

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    Fecal Microbiome Among Nursing Home Residents with Advanced Dementia and Clostridium difficile
    (Springer New York LLC, 2018-06) Araos, Rafael; Andreatos, Nikolaos; Ugalde, Juan; Mitchell, Susan; Mylonakis, Eleftherios; D’Agata, Erika M. C.
    Background/Objectives: Patients colonized with toxinogenic strains of Clostridium difficile have an increased risk of subsequent infection. Given the potential role of the gut microbiome in increasing the risk of C. difficile colonization, we assessed the diversity and composition of the gut microbiota among long-term care facility (LTCF) residents with advanced dementia colonized with C. difficile. Design: Retrospective analysis of rectal samples collected during a prospective observational study. Setting: Thirty-five nursing homes in Boston, Massachusetts. Participants: Eighty-seven LTCF residents with advanced dementia. Measurements: Operational taxonomic units were identified using 16S rRNA sequencing. Samples positive for C. difficile were matched to negative controls in a 1:3 ratio and assessed for differences in alpha diversity, beta diversity, and differentially abundant features. Results: Clostridium difficile sequence variants were identified among 7/87 (8.04%) residents. No patient had evidence of C. difficile infection. Demographic characteristics and antimicrobial exposure were similar between the seven cases and 21 controls. The overall biodiversity among cases and controls was reduced with a median Shannon index of 3.2 (interquartile range 2.7–3.9), with no statistically significant differences between groups. The bacterial community structure was significantly different among residents with C. difficile colonization versus those without and included a predominance of Akkermansia spp., Dermabacter spp., Romboutsia spp., Meiothermus spp., Peptoclostridium spp., and Ruminococcaceae UGC 009. Conclusion: LTCF residents with advanced dementia have substantial dysbiosis of their gut microbiome. Specific taxa characterized C. difficile colonization status. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
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    Isolation of Ciprofloxacin and Ceftazidime-Resistant Enterobacterales From Vegetables and River Water Is Strongly Associated With the Season and the Sample Type
    (Frontiers Media S.A, 2021-09) Díaz Gavidia, Constanza; Barría, Carla; Rivas, Lina; García, Patricia; Alvarez, Francisca P.; González Rocha, Gerardo; Opazo Capurro, Andrés; Araos, Rafael; Munita, José M.; Cortes, Sandra; Olivares Pacheco, Jorge; Adell, Aiko D.; Moreno-Switt, Andrea I.
    The dissemination of antibiotic-resistant bacteria (ARB) from water used for crop irrigation to vegetables is poorly studied. During a year, five farmer markets in a city in Central Chile were visited, and 478 vegetable samples (parsleys, corianders, celeries, lettuces, chards, and beets) were collected. Simultaneously, 32 water samples were collected from two rivers which are used to irrigate the vegetables produced in the area. Resistant Enterobacterales were isolated and identified. Colistin resistance gene mcr-1 and extended spectrum β-lactamases (ESBL) were molecularly detected. The association of environmental factors was evaluated, with the outcomes being the presence of Enterobacterales resistant to four antibiotic families and the presence of multidrug resistance (MDR) phenotypes. Parsley, coriander, and celery showed the highest prevalence of resistant Enterobacterales (41.9% for ciprofloxacin and 18.5% for ceftazidime). A total of 155 isolates were obtained, including Escherichia coli (n=109), Citrobacter sp. (n=20), Enterobacter cloacae complex (n=8), Klebsiella pneumoniae (n=8), and Klebsiella aerogenes (n=1). Resistance to ampicillin (63.2%) and ciprofloxacin (74.2%) was most frequently found; 34.5% of the isolates showed resistance to third-generation cephalosporins, and the MDR phenotype represented 51.6% of the isolates. In two E. coli isolates (1.29%), the gene mcr-1 was found and ESBL genes were found in 23/62 isolates (37%), with blaCTX-M being the most frequently found in 20 isolates (32%). Resistant Enterobacterales isolated during the rainy season were less likely to be MDR as compared to the dry season. Understanding environmental associations represent the first step toward an improved understanding of the public health impact of ARB in vegetables and water. © Copyright © 2021 Díaz-Gavidia, Barría, Rivas, García, Alvarez, González-Rocha, Opazo-Capurro, Araos, Munita, Cortes, Olivares-Pacheco, Adell and Moreno-Switt.
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    Reduced microbial diversity of the nasopharyngeal microbiome in household contacts with latent tuberculosis infection
    (Nature Research, 2023-12) Ruiz-Tagle, Cinthya; Ugalde, Juan A.; Naves, Rodrigo; Araos, Rafael; García, Patricia; Balcells, María Elvira
    The upper respiratory tract is an obliged pathway for respiratory pathogens and a healthy microbiota may support the host's mucosal immunity preventing infection. We analyzed the nasopharyngeal microbiome in tuberculosis household contacts (HHCs) and its association with latent tuberculosis infection (TBI). A prospective cohort of HHCs was established and latent TBI status was assessed by serial interferon-γ release assay (IGRA). Nasopharyngeal swabs collected at baseline were processed for 16S rRNA gene sequencing. The 82 participants included in the analysis were classified as: (a) non-TBI [IGRA negative at baseline and follow-up, no active TB (n = 31)], (b) pre-TBI [IGRA negative at baseline but converted to IGRA positive or developed active TB at follow-up (n = 16)], and (c) TBI [IGRA positive at enrollment (n = 35)]. Predominant phyla were Actinobacteriota, Proteobacteria, Firmicutes and Bacteroidota. TBI group had a lower alpha diversity compared to non-TBI (padj = 0.04) and pre-TBI (padj = 0.04). Only TBI and non-TBI had beta diversity differences (padj = 0.035). Core microbiomes’ had unique genera, and genus showed differential abundance among groups. HHCs with established latent TBI showed reduced nasopharyngeal microbial diversity with distinctive taxonomical composition. Whether a pre-existing microbiome feature favors, are a consequence, or protects against Mycobacterium tuberculosis needs further investigation. © 2023, The Author(s).