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Orcales, F.

Publications and source records attributed to Orcales, F..

2 recordsLinked to original sources

Using a decision tree to predict COVID case numbers: a tutorial for beginners

This manuscript describes the development of a module that is part of a learning platform named "NIGMS Sandbox for Cloud-based Learning" https://github.com/NIGMS/NIGMS-Sandbox. The overall genesis of the Sandbox is described in the editorial NIGMS Sandbox at the beginning of this Supplement. This module delivers learning materials on machine learning and decision tree concepts in an interactive format that uses appropriate cloud resources for data access and analyses. Machine learning (ML) is an important tool in biomedical research and can lead to improvements in diagnosis, treatment, and prevention of diseases. During the COVID pandemic ML was used for predictions at the patient and community levels. Given its ubiquity, it is important that future doctors, researchers and teachers get acquainted with ML and its contributions to research. Our goal is to make it easier for everyone to learn about machine learning. The learning module we present here is based on a small COVID dataset, videos, annotated code and the use of Google Colab or the Google Cloud Platform (GCP). The benefit of these platforms is that students do not have to set up a programming environment on their computer which saves time and is also an important democratization factor. The module focuses on learning the basics of decision trees by applying them to COVID data. It introduces basic terminology used in supervised machine learning and its relevance to research. Our experience with biology students at San Francisco State University suggests that the material increases interest in ML.

scientific communication and education↗

A phylogenetic approach to studying the roles of within-host evolution and between-host transmission of resistance for clinical Escherichia coli infections

Bacterial antibiotic resistance represents a public health concern that will remain relevant for the foreseeable future. Antibiotic resistant bacterial infections can occur in two ways: (1) a host is infected by a resistant bacterial strain (due to between-host transmission of resistance), or (2) a host is infected infection by a susceptible strain, followed by the de novo evolution or acquisition of resistance (due to within-host evolution of resistance). While both are critical to understanding how the evolution of resistance happens in natural settings, the relative rate at which they occur is unclear. Here, we employ phylogenetic comparative methods to examine the evolutionary dynamics of resistance in Escherichia coli for multiple common antibiotics. We report evolutionary patterns consistent with common de novo evolution of resistance for some antibiotics and sustained transmission of resistant strains for others. For example, we observe 79 putative de novo resistance evolution events for resistance to Cefuroxime but only 31 for resistance to Ciprofloxacin, despite similar numbers of observed infections (239 and 267 respectively). We find that clusters of resistance are generally larger for Ciprofloxacin, Ceftazidima and AmoxiClav, which suggests that for these drugs, resistance is often transmitted from patient to patient. In contrast, we find that cluster sizes for resistance are generally smaller for PipTaz, Cefuroxime and Gentamicin, suggesting that resistance to these drugs is less often transmitted from patient to patient and instead evolves de novo. In addition to differences between drugs, we also find that cluster sizes were generally larger in phylogroup B2 compared to the other phylogroups, suggesting that transmission of resistant strains is more common in this phylogroup compared to the others. Our study proposes new approaches for determining the importance of de novo evolution or acquisition (within-host evolution) from resistance from infection with an already resistant strain (between-host transmission). Significantly, this work also bridges an important gap between evolutionary genomics and epidemiology, opening up a range of opportunities for studying the evolutionary dynamics of bacterial antibiotic resistance.

evolutionary biology↗