- 5/5/23 - 5 forms, 1 itemgroup, 15 items, 1 language
Itemgroup: pht006054
Principal Investigator: Sarah Highlander, PhD, J Craig Venter Institute, La Jolla, CA, USA MeSH: Diarrhea,Escherichia coli,Salmonella,Campylobacter,Norovirus,Astroviridae,Adenoviridae,Gastroenteritis,Rotavirus https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs001260 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. 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.

Eligibility

1 itemgroup 20 items

pht006051.v1.p1

1 itemgroup 5 items

pht006052.v1.p1

1 itemgroup 5 items

pht006053.v1.p1

1 itemgroup 16 items
- 2/28/23 - 5 forms, 1 itemgroup, 21 items, 1 language
Itemgroup: IG.elig
Principal Investigator: Sarah Highlander, PhD, J Craig Venter Institute, La Jolla, CA, USA MeSH: Diarrhea,Escherichia coli,Salmonella,Campylobacter,Norovirus,Astroviridae,Adenoviridae,Gastroenteritis,Rotavirus https://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?study_id=phs001352 Traveler's diarrhea (TD) is caused by enterotoxigenic Escherichia coli (ETEC), other pathogenic gram-negative pathogens, norovirus and some parasites. Nevertheless, standard diagnostic methods fail to identify pathogens in more than 30% of TD patients, so it is predicted that new pathogens or groups of pathogens may be causative agents of disease. A comprehensive metagenomic study of the fecal microbiomes from 23 TD patients and seven healthy travelers was performed, all of which tested negative for the known etiologic agents of TD in standard tests. Metagenomic reads were assembled and the resulting contigs were subjected to semi-manual binning to assemble independent genomes from metagenomic pools. Taxonomic and functional annotations were conducted to assist identification of putative pathogens. We extracted 560 draft genomes, 320 of which were complete enough to be enough characterized as cellular genomes and 160 of which were bacteriophage genomes. We made predictions of the etiology of disease in individual subjects based on the properties and features of the recovered cellular genomes. Three subtypes of samples were observed. First were four patients with low diversity metagenomes that were predominated by one or more pathogenic E. coli strains. Annotation allowed prediction of pathogenic type in most cases. Second, five patients were co-infected with E. coli and other members of the Enterobacteriaceae, including antibiotic resistant Enterobacter, Klebsiella, and Citrobacter. Finally, several samples contained genomes that represented dark matter. In one of these samples we identified a TM7 genome that phylogenetically clustered with a strain isolated from wastewater and carries genes encoding potential virulence factors. We also observed a very high proportion of bacteriophage reads in some samples. The relative abundance of phage was significantly higher in healthy travelers when compared to TD patients. Our results highlight that assembly-based analysis revealed that diarrhea is often polymicrobial and includes members of the Enterobacteriaceae not normally associated with TD and have implicated a new member of the TM7 phylum as a potential player in diarrheal disease.

pht007064.v1.p1

1 itemgroup 4 items

pht007065.v1.p1

1 itemgroup 5 items

pht007066.v1.p1

1 itemgroup 2 items

pht007067.v1.p1

1 itemgroup 6 items
- 6/21/17 - 1 form, 1 itemgroup, 4 items, 1 language
Itemgroup: Registration
- 2/15/16 - 1 form, 1 itemgroup, 1 item, 1 language
Itemgroup: Investigator's electronic signature
- 2/15/16 - 1 form, 1 itemgroup, 2 items, 1 language
Itemgroup: Comment Log
- 2/15/16 - 1 form, 1 itemgroup, 12 items, 1 language
Itemgroup: Adverse event
- 2/11/16 - 1 form, 3 itemgroups, 14 items, 1 language
Itemgroups: Current contact, Stool frequency and consistency, Intake of investigational agent
- 2/11/16 - 1 form, 2 itemgroups, 13 items, 1 language
Itemgroups: Antibiotics, Further medication subject to documentation
Antibiotic-associated diarrhoea (AAD) is a frequent condition in hospitalised patients receiving antibiotic treatment. The same is true for Clostridium difficile-associated diarrhoea (CDAD) with even more grave consequences of increased morbidity and mortality. The development and evaluation of preventive strategies is one key public health challenge. In the absence of clinically evaluated alternatives, probiotics have been suggested to be beneficial for the prevention of AAD and CDAD. However, data have so far been inconclusive and recently published meta-analyses strongly recommended large state-of-the-art clinical trials on probiotic substances for the prevention of AAD and CDAD. Since the efficacy, side-effects and modes of action of different probiotic bacteria and yeast are strain specific, benefits and risks cannot be generalised. The non-pathogenic yeast Saccharomyces cerevisiae var. boulardii (Sac. boulardii) is considered the most promising probiotic substance for the prevention of AAD and CDAD. We carry out a randomised, placebo controlled, double blind multicentre clinical trial to evaluate Sac. boulardii for the indication of prevention of AAD and CDAD in 1520 adult, hospitalised patients. Please note: 1) At first hospitalization please enter the antibiotic initially used in the first line! 2) Please enter the medication in chronological order! 3) Obligatory documentation starts with the date the (re-) hospitalization begins! If there is preexisting medication the starting date is determined as follows: a) First hospitalization = Date of first dose of antibiotic! b) Rehospitalization = Date of Rehospitalization! 4) Documentation of the last dose of any of the medication subject for documentation is only necessary until the regular end of the study.
- 2/11/16 - 1 form, 3 itemgroups, 13 items, 1 language
Itemgroups: Examination date, CRP, Leukocytes
- 2/11/16 - 1 form, 1 itemgroup, 4 items, 1 language
Itemgroup: Readmission
- 2/11/16 - 1 form, 1 itemgroup, 1 item, 1 language
Itemgroup: Revisit/Rehospitalization Necessary?
- 2/11/16 - 1 form, 1 itemgroup, 7 items, 1 language
Itemgroup: Information according to the data obtained

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