Biology subjects

Araos, R.

Publications and source records attributed to Araos, R..

5 recordsLinked to original sources

bioRxiv2025

BugBuster: A novel automatic and reproducible workflow for metagenomic data analysis

SummaryIn metagenomic sequencing, large volumes of data are obtained with all the genetic information present in a sample, allowing valuable data to be obtained about microbial communities. The software and processes necessary to obtain quality results have become increasingly complex and sophisticated, limiting the accessibility of biologists who try to use them. To facilitate the analysis of this data, a modular and reproducible workflow was developed using the Nextflow workflow orchestrator named BugBuster. The pipeline is easy to implement because all its dependencies are provided within containers, it is reproducible, modular and portable. BugBuster consists of different processes that allow data analysis at the level of reads, contigs and MAGs, also including modules for resistome characterization and taxonomic profiling. Availability and implementationBugBuster was written in Nextflow DSL2 Syntaxis. The program applications, user manual, exemplary data and code are freely available at https://github.com/gene2dis/BugBuster.

bioinformatics↗

bioRxiv2023

Heavy Metal Pollution From a Major Earthquake and Tsunami in Chile Is Associated With Geographic Divergence of Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Latin America

Methicillin-resistant Staphylococcus aureus (MRSA) is a priority pathogen listed by the World Health Organization. The global spread of MRSA is characterized by successive waves of epidemic clones that predominate in specific geographical regions. The acquisition of genes encoding resistance to heavy-metals is thought to be a key feature in the divergence and geographical spread of MRSA. Increasing evidence suggests that extreme natural events, such as earthquakes and tsunamis, could release heavy-metals into the environment. However, the impact of environmental exposition to heavy-metals on the divergence and spread of MRSA clones has been insufficiently explored. We assess the association between a major earthquake and tsunami in an industrialized port in southern Chile and MRSA clone divergence in Latin America. We performed a phylogenomic reconstruction of 113 MRSA clinical isolates from seven Latin American healthcare centers, including 25 isolates collected in a geographic area affected by an earthquake and tsunami that led to high levels of heavy-metal environmental contamination. We found a divergence event strongly associated with the presence of a plasmid harboring heavy-metal resistance genes in the isolates obtained in the area where the earthquake and tsunami occurred. Moreover, clinical isolates carrying this plasmid showed increased tolerance to mercury, arsenic, and cadmium. We also observed a physiological burden in the plasmid-carrying isolates in absence of heavy-metals. Our results are the first evidence that suggests that heavy-metal contamination, in the aftermath of an environmental disaster, appears to be a key evolutionary event for the spread and dissemination of MRSA in Latin America.

microbiology↗

bioRxiv2023

Dynamics of the MRSA Population in A Chilean Hospital: A Phylogenomic Analysis (2000-2016)

The global dissemination of methicillin-resistant Staphylococcus aureus (MRSA) is associated with the emergence and establishment of clones in specific geographic areas. The Chilean-Cordobes clone (ChC) (ST5-SCCmecI) has been the predominant MRSA clone in Chile since its first description in 1998, despite the report of other emerging MRSA clones in the last years. Here, we characterize the evolutionary history of MRSA from 2000 to 2016 in a Chilean tertiary healthcare center using phylogenomic analyses. We sequenced 469 MRSA isolates collected between 2000-2016 in a tertiary healthcare center in Chile. We evaluated the temporal trends of the circulating clones and performed a phylogenomic reconstruction to characterize the clonal dynamics. We found a significant increase in the diversity and richness of sequence types (STs; Spearman r=0.8748, p<0.0001) with a Shannon diversity index increasing from 0.221 in the year 2000 to 1.33 in 2016. The temporal trend analysis revealed that in the period 2000-2003 most of the isolates (94.2%; n=98) belonged to the ChC clone. However, since then, the frequency of the ChC clone has decreased over time, accounting for 52% of the collection in the 2013-2016 period. This decline was accompanied by the rise of two emerging MRSA lineages, ST105-SCCmecII and ST72-SCCmecVI. In conclusion, the ChC clone remains the most frequent MRSA lineage in Chile. However, this lineage is gradually being replaced by several emerging clones, the most important of which is clone ST105-SCCmecII. To the best of our knowledge, this is the largest study of MRSA clonal dynamics performed in South America. ImportanceMethicillin-resistant Staphylococcus aureus (MRSA) is a major public health pathogen that disseminates through the emergence of successful dominant clones in specific geographic regions. Knowledge of the dissemination and molecular epidemiology of MRSA in Latin America is scarce and is largely based on small studies or classical typing techniques with several limitations to depict an accurate description of their genomic landscape. We used whole-genome sequencing to study 469 MRSA isolates collected between 2000-2016 in Chile to provide the largest and most detailed study of clonal dynamics of MRSA carried out in South America to date. We found a significant increase in the diversity of MRSA clones circulating over the 17-year study period. Additionally, we describe the emergence of two novel clones (ST105-SCCmecII and ST72-SCCmecVI), which have been gradually increasing their frequency over time. Our results drastically improve our understanding of the dissemination and update our knowledge about MRSA in Latin America.

microbiology↗

bioRxiv2020

Head-to-head comparison of four antigen-based rapid detection tests for the diagnosis of SARS-CoV-2 in respiratory samples

In the context of the Covid-19 pandemic, the development and validation of rapid and easy-to-perform diagnostic methods are of high priority. We compared the performance of four rapid antigen detection tests for SARS-CoV-2 in respiratory samples. Immunochromatographic SARS-CoV-2 assays from RapiGEN, Liming bio, Savant, and Bioeasy were evaluated using universal transport medium containing naso-oropharyngeal swabs from suspected Covid-19 cases. The diagnostic accuracy was determined in comparison to SARS-CoV-2 RT-PCR. A total of 111 samples were included; 80 were RT-PCR positive. Median patients age was 40 years, 55% were female, and 88% presented within the first week after symptom onset. The evaluation of the Liming bio assay was discontinued due to insufficient performance. The overall sensitivity values of RapiGEN, Liming bio, and Bioeasy tests were 62.0% (CI95% 51.0-71.9), 16.7% (CI95% 10.0-26.5), and 85.0% (CI95% 75.6-91.2), respectively, with specificities of 100%. Sensitivity was significantly higher in samples with high viral loads (RapiGEN, 84.9%; Bioeasy, 100%). The study highlighted the significant heterogeneity of test performance among evaluated assays, which might have been influenced by the use of a non-validated sample material. The high sensitivity of some tests demonstrated that rapid antigen detection has the potential to serve as an alternative diagnostic method, especially in patients presenting with high viral loads in early phases of infection. This is particularly important in situations with limited access to RT-PCR or prolonged turnaround time. Further comparative evaluations are necessary to select products with high performance among the growing market of diagnostic tests for SARS-CoV-2.

microbiology↗

bioRxiv2019

Antimicrobial resistance gene levels are independent of levofloxacin administration but related to abundance of specific pathobionts in dementia patients

BackgroundThe issue of antimicrobial resistance continues to grow worldwide, and long-term care facilities are significant reservoirs of antimicrobial-resistant organisms, in part due to high frequency of antimicrobial use. Patients with advanced dementia are particularly vulnerable to multidrug-resistant organism acquisition and antimicrobial overuse, which has negative consequences for the gut microbiome and can contribute to the selection and propagation of antimicrobial resistance genes. In this study, we longitudinally examined a group of advanced dementia patients treated with the fluoroquinolone antimicrobial levofloxacin, finding a correlation between abundance of pathogens and antimicrobial resistance genes, which we confirmed in a larger cohort of subjects with advanced dementia.\n\nResultsWe observed significant inter- and intra-subject heterogeneity in the composition of the microbiota of the longitudinal levofloxacin cohort, suggesting temporal instability. Within this dataset, we did not find significant impacts of levofloxacin on the diversity, composition, function, or resistome of the gut microbiota of this population. However, we were able to link the antimicrobial resistance gene burden in a sample with the relative abundance of several pathobionts - particularly Escherichia coli, Proteus mirabilis, and Enterococcus faecalis, as well as less-prevalent species including Providencia stuartii and Staphylococcus haemolyticus. Furthermore, we used metagenomic assembly and binning to demonstrate that these species had higher genomic resistance gene levels than common gut commensals, and we were able to predict antimicrobial resistance gene burden from the relative abundances of these species in a separate, larger cohort from the same population.\n\nConclusionsWe found that the relative abundances of several pathobionts were correlated with and were even predictive of the level of antimicrobial resistance genes in corresponding samples, and that these species carried high levels of resistances genes in their assembled genomes. In order to test this observation, we utilized a larger metagenomics dataset from a similar population and confirmed the association between pathobiont abundance and antimicrobial resistance genes. Given the high frequency with which these species were found at high levels in this population and the underlying vulnerability to infection with multidrug resistant organisms of advanced dementia patients, attention to microbial blooms of these species may be warranted. Additionally, in this study, we were able to utilize genomic assembly from metagenomic data to more definitively associate antimicrobial resistance gene levels with specific assembled species; as this technology continues to develop, assembly could prove to be a valuable method to monitor both specific resistance genes and blooms of multidrug-resistant organisms.

microbiology↗