Project description:<p>The study of antimicrobial resistance (AMR) in infectious diarrhea has generally been limited to cultivation, antimicrobial susceptibility testing and targeted PCR assays. When individual strains of significance are identified, whole genome shotgun (WGS) sequencing of important clones and clades is performed. Genes that encode resistance to antibiotics have been detected in environmental, insect, human and animal metagenomes and are known as "resistomes". While metagenomic datasets have been mined to characterize the healthy human gut resistome in the Human Microbiome Project and MetaHIT and in a Yanomani Amerindian cohort, directed metagenomic sequencing has not been used to examine the epidemiology of AMR. Especially in developing countries where sanitation is poor, diarrhea and enteric pathogens likely serve to disseminate antibiotic resistance elements of clinical significance. Unregulated use of antibiotics further exacerbates the problem by selection for acquisition of resistance. This is exemplified by recent reports of multiple antibiotic resistance in Shigella strains in India, in Escherichia coli in India and Pakistan, and in nontyphoidal Salmonella (NTS) in South-East Asia. We propose to use deep metagenomic sequencing and genome level assembly to study the epidemiology of AMR in stools of children suffering from diarrhea. Here the epidemiology component will be surveillance and analysis of the microbial composition (to the bacterial species/strain level where possible) and its constituent antimicrobial resistance genetic elements (such as plasmids, integrons, transposons and other mobile genetic elements, or MGEs) in samples from a cohort where diarrhea is prevalent and antibiotic exposure is endemic. The goal will be to assess whether consortia of specific mobile antimicrobial resistance elements associate with species/strains and whether their presence is enhanced or amplified in diarrheal microbiomes and in the presence of antibiotic exposure. This work could potentially identify clonal complexes of organisms and MGEs with enhanced resistance and the potential to transfer this resistance to other enteric pathogens.</p> <p>We have performed WGS, metagenomic assembly and gene/protein mapping to examine and characterize the types of AMR genes and transfer elements (transposons, integrons, bacteriophage, plasmids) and their distribution in bacterial species and strains assembled from DNA isolated from diarrheal and non-diarrheal stools. The samples were acquired from a cohort of pediatric patients and controls from Colombia, South America where antibiotic use is prevalent. As a control, the distribution and abundance of AMR genes can be compared to published studies where resistome gene lists from healthy cohort sequences were compiled. Our approach is more epidemiologic in nature, as we plan to identify and catalogue antimicrobial elements on MGEs capable of spread through a local population and further we will, where possible, link mobile antimicrobial resistance elements with specific strains within the population.</p>
Project description:Diarrhea remains a major cause of death in children. Current diagnostic methods largely rely on stool culture and suffer from low sensitivity and inadequate specificity, often leading to inappropriate treatment. The objective of the present study was to use RNA sequencing (RNAseq) analysis to determine blood transcriptional profiles specific for several common pathogenic bacteria and viruses that cause diarrhea in children. We collected whole blood samples from children in Mexico having diarrhea associated with a single pathogen and without systemic complications. Our RNAseq data suggested that the blood signatures can differentiate children with diarrhea from healthy children either with or without bacterial colonization. Moreover, we detected different expression profiles from bacterial and viral infection, demonstrating for the first time the use of RNAseq to identify the etiology of infectious diarrhea. Whole blood from 207 children including children with diarrhea caused by rotavirus (n=55), E.coli (n=55), Salmonella (n=36), Shigella (n=37) and control children (n=24).
Project description:Diarrhea remains a major cause of death in children. Current diagnostic methods largely rely on stool culture and suffer from low sensitivity and inadequate specificity, often leading to inappropriate treatment. The objective of the present study was to use RNA sequencing (RNAseq) analysis to determine blood transcriptional profiles specific for several common pathogenic bacteria and viruses that cause diarrhea in children. We collected whole blood samples from children in Mexico having diarrhea associated with a single pathogen and without systemic complications. Our RNAseq data suggested that the blood signatures can differentiate children with diarrhea from healthy children either with or without bacterial colonization. Moreover, we detected different expression profiles from bacterial and viral infection, demonstrating for the first time the use of RNAseq to identify the etiology of infectious diarrhea.
Project description:Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Using a mouse model mimicking pediatric antibiotic use, we found that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide altered both host and microbiota development. Early-life PAT accelerated total mass and bone growth, and resulted in progressive changes in gut microbiome diversity, population structure, and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. While control microbiota rapidly adapted to a change in diet, PAT slowed the ecological progression, with delays lasting several months in response to the macrolide. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment.
Project description:Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Using a mouse model mimicking pediatric antibiotic use, we found that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide altered both host and microbiota development. Early-life PAT accelerated total mass and bone growth, and resulted in progressive changes in gut microbiome diversity, population structure, and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. While control microbiota rapidly adapted to a change in diet, PAT slowed the ecological progression, with delays lasting several months in response to the macrolide. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment. C57BL/6J mice received three antibiotic courses: at days 10-15, 28-31, and 37-40 of life, amoxicillin or tylosin.Livers were collected at age 22 weeks, RNA was extracted, and transcriptional differences were measured by microarray analysis.
Project description:Antimicrobial resistance (AMR) is a global health crisis that is predicted to worsen. While improper antibiotic usage is an established driver, less is known on the impacts of metal supplements. Here, we probe the impact of zinc (Zn) on AMR. In conflict settings where diarrhea disease cases are high, Zn, which is associated with weapons of war, is given as a supplement for diarrhea treatment prior to antibiotics such as ciprofloxacin. In this study, we find that E. coli’s exposure order to zinc impacts resistance development, with increasing pre-exposure leading to accelerated ciprofloxacin resistance, while combined exposure of zinc with ciprofloxacin delays ciprofloxacin resistance. We did not find evidence that zinc pre-exposure leads to genetic changes or changes in antibiotic tolerance, though the lag phase and doubling time of E. coli was increased, suggesting gene expression may be changed. While the zinc phenotype was no longer observed if ciprofloxacin exposure did not occur right after zinc pre-exposure, the resulting elevated MIC was more stable. These results are important as they highlight the need to reexamine the clinical role of zinc in treating diarrheal diseases and assess if changes in resistance development observed in vitro are also observed in vivo.
Project description:Porcine epidemic diarrhea (PED) is an acute, highly contagious, and high-mortality enterophilic infectious disease caused by the porcine epidemic diarrhea virus (PEDV). PEDV is globally endemic and causes substantial economic losses in the swine industry. The PEDV E protein is the smallest structural protein with high expression levels that interacts with the M protein and participates in virus assembly. However, how the host proteins interact with E proteins in PEDV replication remains unknown. We identified host proteins that interact with the PEDV E protein using a combination of PEDV E protein-labeled antibody co-immunoprecipitation and tandem liquid-chromatography mass-spectroscopy (LC-MS/MS).
Project description:Sixty crossbred piglets (Duroc*Landrace*Yorkshire) weaned at the age of 21 days were maintained for one week and had free access to feed and water. During this week, all the piglets were scored for the severity of diarrhea. Diarrhea index was scored as follows: 1= hard feces; 2= no scours, feces of normal consistency; 3= mild scours, soft, partially formed feces; 4= moderate scours, loose, semi-liquid feces; 5= watery feces; as previously did Those piglets with a score of 4 or 5 for three continuous days were designated as diarrhea piglets, while those piglets with a score of 1 or 2 for three continuous days were designated as normal piglets..