A5023488978- Viral gastroenteritis research and epidemiology
- Escherichia coli research studies
- Vibrio bacteria research studies
- Salmonella and Campylobacter epidemiology
- Probiotics and Fermented Foods
- Antibiotic Resistance in Bacteria
- Bacteriophages and microbial interactions
- Alcoholism and Thiamine Deficiency
- Immune Response and Inflammation
- Gut microbiota and health
- Bacterial Infections and Vaccines
- Antimicrobial Peptides and Activities
- Diet and metabolism studies
- Trace Elements in Health
- Infant Nutrition and Health
- Clostridium difficile and Clostridium perfringens research
- Aquaculture disease management and microbiota
- Influenza Virus Research Studies
- Electrolyte and hormonal disorders
- Metabolism and Genetic Disorders
- Folate and B Vitamins Research
- Glycosylation and Glycoproteins Research
- Child Nutrition and Water Access
- Hepatitis B Virus Studies
- Blood groups and transfusion
Washington University in St. Louis
2015-2025
International Centre for Diarrhoeal Disease Research
2009-2017
Massachusetts General Hospital
2007-2014
Arizona State University
2014
Harvard University
2010-2014
Thermo Fisher Scientific (United States)
2010
University Medical Center
2010
Tufts University
2010
ABSTRACT Enterotoxigenic Escherichia coli (ETEC) is a leading cause of death due to diarrheal illness among young children in developing countries, and there currently no effective vaccine. Many elements ETEC pathogenesis are still poorly defined. Here we demonstrate that YghJ, secreted antigen identified immunoproteomic studies using convalescent patient sera, required for efficient access small intestinal enterocytes the optimal delivery heat-labile toxin (LT). Furthermore, YghJ highly...
Enterotoxigenic Escherichia coli (ETEC) is a major cause of morbidity and mortality due to infectious diarrhea in developing countries for which there presently no effective vaccine. A central challenge ETEC vaccinology has been the identification conserved surface antigens formulate broadly protective Here, we demonstrate that EatA, an immunogenic secreted serine protease ETEC, contributes virulence by degrading MUC2, protein present small intestinal mucous layer, removal this barrier vitro...
Natural selection in a Bangladeshi population from the cholera-endemic Ganges River Delta has targeted genes associated with cholera resistance and an innate immunity pathway activated by Vibrio cholerae .
Enterotoxigenic Escherichia coli (ETEC) are common causes of diarrheal morbidity and mortality in developing countries for which there is currently no vaccine. Heterogeneity classical ETEC antigens known as colonization factors (CFs) poor efficacy toxoid-based approaches to date have impeded development a broadly protective vaccine, prompting searches novel molecular targets.Using variety methods, we examined large collection isolates production two secreted plasmid-encoded...
Background Enterotoxigenic Escherichia coli (ETEC) is a common cause of bacterial infection leading to acute watery diarrhea in infants and young children as well travellers ETEC endemic countries. Ciprofloxacin broad-spectrum antimicrobial agent nowadays used for the treatment diarrhea. This study aimed characterize ciprofloxacin resistant strains isolated from diarrheal patients Bangladesh. Methods A total 8580 stool specimens attending icddr,b Dhaka hospital was screened between 2005...
Enterotoxigenic Escherichia coli (ETEC) strains are a leading cause of morbidity and mortality due to diarrheal illness in developing countries. There is currently no effective vaccine against these important pathogens. Because genes modulated by pathogen-host interactions potentially encode putative targets, we investigated changes gene expression surface morphology ETEC upon interaction with intestinal epithelial cells vitro. Pan-genome microarrays, quantitative reverse transcriptase PCR...
Background Rapid and reliable diagnostic assays for enteric (typhoid paratyphoid) fever are urgently needed. We report the characterization of novel approach utilizing lymphocyte secretions, diagnosing patients with by TPTest procedure. Methodology detects Salmonella-specific IgA responses in culture supernatant. utilized suspected fever, other illnesses, healthy controls. also evaluated simplified modifications adaptation laboratories limited facilities equipment. Principal Findings was...
Enterotoxigenic Escherichia coli (ETEC) infections are highly prevalent in developing countries, where clinical presentations range from asymptomatic colonization to severe cholera-like illness. The molecular basis for these varied presentations, which may involve strain-specific virulence features as well host factors, has not been elucidated. We demonstrate that, when challenged with ETEC strain H10407, originally isolated a case of illness, blood group A human volunteers developed...
Enterotoxigenic Escherichia coli (ETEC), defined by their elaboration of heat-labile (LT) and/or heat-stable (ST) enterotoxins, are a common cause diarrheal illness in developing countries. Efficient delivery these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using variety pathovar-specific and conserved E. adhesin molecules as well plasmid encoded colonization factors. Some adhesins undergo significant transcriptional modulation encounter...
Enterotoxigenic E. coli (ETEC) produce heat-labile (LT) and/or heat-stable (ST) enterotoxins, and commonly cause diarrhea in resource-poor regions. ETEC have been linked repeatedly to sequelae children including enteropathy, malnutrition, growth impairment. Although cellular actions of enterotoxins leading are well-established, their contributions remain unclear. LT increases cAMP activate protein kinase A (PKA) that phosphorylates ion channels driving intestinal export salt water resulting...
Enterotoxigenic E. coli (ETEC) cause hundreds of millions cases acute diarrheal illness in low-middle income regions, disproportionately young children. To date there is no licensed, broadly protective vaccine to protect against these common but antigenically heterogeneous pathogens. One the more highly conserved antigens ETEC, EtpA, an extracellular glycoprotein adhesin that preferentially binds blood group A glycans on intestinal epithelia. EtpA contributes increased severity individuals,...
Salmonella enterica serotype Paratyphi A is a human-restricted cause of paratyphoid fever, accounting for up to fifth all cases enteric fever in Asia.In this work, we applied an RNA analysis method, Selective Capture Transcribed Sequences (SCOTS), and cDNA hybridization-microarray technology identify S. transcripts expressed by bacteria the blood three patients Bangladesh. In total, detected 1,798 mRNAs infected humans (43.9% ORFeome). Of these, identified 868 at least two patients, 315...
Background S. Typhi, a human-restricted Salmonella enterica serovar, causes systemic intracellular infection in humans (typhoid fever). In comparison, Typhimurium gastroenteritis humans, but typhoidal illness mice. The PhoP regulon is well studied two component (PhoP/Q) coordinately regulated network of genes whose expression required for survival enterica. Methodology/Principal Findings Using high performance liquid chromatography mass spectrometry (HPLC-MS/MS), we examined the protein...
ABSTRACT Enterotoxigenic E. coli (ETEC) can cause severe diarrhea and death in children developing countries; however, bacterial diversity natural infection is uncharacterized. In this study, we explored the population variation of ETEC from individuals with cholera-like diarrhea. Genomic sequencing comparative analysis multiple isolates twelve cases demonstrated clonal populations majority subjects (10/12). contrast, a minority (2/12) yielded phylogenomically divergent isolates. Detailed...
ABSTRACT Clostridium difficile is the leading cause of nosocomial infectious diarrhea. C. produces two toxins (A and B), systemic mucosal anti-toxin A antibodies prevent or limit -associated To evaluate whether transcutaneous immunization with formalin-treated toxin (CDA) induces anti-CDA immune responses, we transcutaneously immunized three cohorts mice CDA without immunoadjuvantative cholera (CT) on days 0, 14, 28, 42. Mice CT developed prominent anti-CT immunoglobulin G (IgG) IgA...
ABSTRACT Salmonella enterica serotype Typhi is the cause of typhoid fever and a human-restricted pathogen. Currently available vaccines provide 50 to 90% protection for 2 5 years, practical diagnostic assays identify individuals with lack sensitivity and/or specificity. Identifying immunogenic S . antigens expressed during human infection could lead improved vaccines. Here we describe platform i mmunoaffinity p roteomics-based t echnology (IPT) that involves use columns charged IgG, IgM, or...
ABSTRACT Many currently available diagnostic tests for typhoid fever lack sensitivity and/or specificity, especially in areas of the world where disease is endemic. In order to identify a test that better correlates with fever, we evaluated immune responses Salmonella enterica serovar Typhi (serovar Typhi) individuals suspected Dhaka, Bangladesh. We enrolled 112 cultured day 0 blood organisms, and performed Widal assays on days 0, 5, 20. harvested peripheral lymphocytes analyzed antibody...
ABSTRACT Vibrio cholerae O1 can cause diarrheal disease that may be life-threatening without treatment. Natural infection results in long-lasting protective immunity, but the role of T cells this immune response has not been well characterized. In contrast, robust B-cell responses to V. have observed. particular, memory T-cell-dependent antigens persist for at least 1 year, whereas lipopolysaccharide, a T-cell-independent antigen, wane more rapidly after infection. We hypothesize immunity is...
Salmonella enterica serotype Typhi is the cause of typhoid fever. It a human-restricted pathogen, and few data exist on S. gene expression in humans.We applied an RNA capture amplification technique, Selective Capture Transcribed Sequences (SCOTS), microarray hybridization to identify transcripts expressed blood five humans infected with Bangladesh. In total, we detected mRNAs for 2,046 genes (44% genome) human blood; 912 was all 5 patients, 1,100 4 or more patients. Identified were...
Background Children bear a large burden of typhoid fever caused by Salmonella enterica serotype Typhi (S. Typhi) in endemic areas. However, immune responses and clinical findings children are not well defined. Here, we describe immunological characteristics young with S. bacteremia, antimicrobial susceptibility patterns isolated strains. Methods As marker recent infection, have previously characterized antibody-in-lymphocyte secretion (TPTest) during acute adults. We similarly assessed...
Abstract Enterotoxigenic Escherichia coli (ETEC) cause more than 500,000 deaths each year in the developing world and are characterized on a molecular level by presence of genes that encode heat-stable (ST) and/or heat-labile (LT) enterotoxins, as well surface structures, known colonization factors (CFs). Genome sequencing comparative genomic analyses 94 previously uncharacterized ETEC isolates demonstrated remarkable diversity, with 28 distinct sequence types identified three phylogenomic...
ABSTRACT Enterotoxigenic Escherichia coli (ETEC) strains are among the most common causes of diarrheal illness worldwide. These pathogens disproportionately afflict children in developing countries, where they cause substantial morbidity and responsible for hundreds thousands deaths each year. Although these organisms important targets enteric vaccines, development efforts to date have centered on a subset plasmid-encoded fimbrial adhesins known as colonization factors heat-labile toxin...