A5045918526- Salmonella and Campylobacter epidemiology
- Vibrio bacteria research studies
- Escherichia coli research studies
- Viral gastroenteritis research and epidemiology
- Bacteriophages and microbial interactions
- Aquaculture disease management and microbiota
- Listeria monocytogenes in Food Safety
- Antibiotic Resistance in Bacteria
- Bacterial Genetics and Biotechnology
- Health and Medical Education
- Insect symbiosis and bacterial influences
- Aging, Health, and Disability
- Gut microbiota and health
- Reproductive tract infections research
- Cancer Research and Treatments
- CRISPR and Genetic Engineering
- Microbial infections and disease research
- Transgenic Plants and Applications
- Pharmaceutical and Antibiotic Environmental Impacts
- Health and Medical Research Impacts
- Latin American Urban Studies
- Educational theories and practices
- Identification and Quantification in Food
- Educational methodologies and cognitive development
- Yersinia bacterium, plague, ectoparasites research
Universidad Andrés Bello
2019-2024
Universidad Autónoma de Chile
2018-2020
Harvard University
2016-2019
Brigham and Women's Hospital
2016-2019
University of Chile
2007-2015
Fundación Chile
2012
The genus Salmonella contains two species, S. bongori and enterica. Compared to the well-studied enterica there is a marked lack of information regarding genetic makeup diversity bongori. has been found predominantly associated with cold-blooded animals, but it can infect humans. To define phylogeny this compare enterica, we have sequenced 28 isolates representing most known This cross-species analysis allowed us confidently differentiate ancestral functions from those acquired following...
Abstract Background The recently described Type VI Secretion System (T6SS) represents a new paradigm of protein secretion in bacteria. A number bioinformatic studies have been conducted to identify T6SS gene clusters the available bacterial genome sequences. According these studies, Salmonella harbors unique encoded Pathogenicity Island 6 (SPI-6). Since only considered few genomes, present work aimed novel loci by silico analysis every sequence available. Results sequencing data from 44...
We constructed two collections of targeted single gene deletion (SGD) mutants and multi-gene (MGD) in Salmonella enterica sv Typhimurium 14028s. The SGD mutant contain (1), 3517 which a is replaced by cassette containing kanamycin resistance (KanR) oriented the sense direction (SGD-K), (2), 3376 with chloramphenicol (CamR) antisense (SGD-C). A combined total 3773 individual genes were deleted across these collections. MGD bearing deletions contiguous regions three or more include (3), 198...
Significance We conducted a genome-wide screen to identify bacterial factors required for Vibrio parahaemolyticus , an important cause of seafood-borne gastroenteritis, survive in vitro and colonize the mammalian intestine. Our analysis revealed uncharacterized components horizontally acquired type III secretion system linked virulence (T3SS2) hundreds genes that likely contribute colonization independent T3SS2. work toxR conserved gene vibrios governs expression cholerae was critical Thus,...
ABSTRACT Salmonella enterica serovar Enteritidis causes a systemic, typhoid-like infection in newly hatched poultry and mice. In the present study, library of 54,000 transposon mutants S. phage type 4 (PT4) strain P125109 was screened for deficient vivo colonization BALB/c mouse model using microarray-based negative-selection screening. Mutants genes known to contribute systemic (e.g., pathogenicity island 2 [SPI-2], aro , rfa rfb phoP phoQ ) enteric SPI-1 SPI-5) this other serovars...
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is an important food-borne pathogen that colonizes the colon. Transposon-insertion sequencing (TIS) was used to identify genes required for EHEC and E. K-12 growth in vitro vivo infant rabbit Surprisingly, many conserved loci contribute EHEC’s but not K-12’s vitro. There a restrictive bottleneck colonization of colon, which complicated identification facilitating vivo. Both refined version existing analytic framework as well PCA-based...
The amount of lipopolysaccharide (LPS) O antigen (OAg) and its chain length distribution are important factors that protect bacteria from serum complement. Salmonella enterica serovar Typhi produces LPS with long (L-OAg) controlled by the wzz gene, whereas Typhimurium two OAg lengths: an L-OAg WzzST a very (VL) determined WzzfepE. This study shows Enteritidis also has bimodal preferred lengths similar to Typhimurium. It was reported previously production S. increases at late exponential...
Salmonella Gallinarum is a pathogen with host range specific to poultry, while Enteritidis broad that colonizes poultry sub-clinically but leading cause of gastrointestinal salmonellosis in humans and many other species. Despite recent advances our understanding the complex interplay between their hosts, molecular basis restriction unique pathobiology remain largely unknown. Type VI Secretion System (T6SS) represents new paradigm protein secretion critical for pathogenesis Gram-negative...
ABSTRACT Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. We have reported S . harbors type VI secretion system (T6SS) encoded pathogenicity island 19 (SPI-19) required for efficient colonization chicks. In present study, we aimed to characterize SPI-19 T6SS functionality investigate mechanisms behind phenotypes previously observed vivo Expression...
Enterohemorrhagic Escherichia coli (EHEC) has two critical virulence factors-a type III secretion system (T3SS) and Shiga toxins (Stxs)-that are required for the pathogen to colonize intestine cause diarrheal disease. Here, we carried out a genome-wide CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats with Cas9) loss-of-function screen identify host loci that facilitate EHEC infection of intestinal epithelial cells. Many guide RNAs identified targeted known be associated...
Campylobacter jejuni and coli are the leading cause of human gastroenteritis in industrialized world an emerging threat developing countries. The incidence campylobacteriosis South America is greatly underestimated, mostly due to lack adequate diagnostic methods. Accordingly, there limited genomic epidemiological data from this region. In present study, we performed a genome-wide analysis genetic diversity, virulence, antimicrobial resistance largest collection clinical C . strains Chile...
Abstract The type VI secretion system (T6SS) is a virulence factor for many Gram-negative bacteria. S almonella genus harbors five phylogenetically distinct T6SS loci encoded in Salmonella Pathogenicity Islands (SPIs) SPI-6, SPI-19, SPI-20, SPI-21 and SPI-22, which are differentially distributed among serotypes. T6SSs SPI-6 SPI-19 contribute to pathogenesis of serotypes Typhimurium Gallinarum mice chickens, respectively. Dublin pathogen restricted cattle where it causes systemic disease....
The role of the Salmonella Pathogenicity Islands (SPIs) in pathogenesis enterica Typhimurium infection chicken is poorly studied, while many studies have been completed murine models. Type VI Secretion System (T6SS) a recently described protein secretion system Gram-negative bacteria. genus contains five phylogenetically distinct T6SS encoded differentially distributed genomic islands. S. harbors SPI-6 (T6SSSPI-6), which contributes to ability colonize mice. On other hand, serotype...
IntroductionE. coli is a ubiquitous bacterium commonly used as sentinel in antimicrobial resistance studies. Here, E. was isolated from three groups (sick calves, healthy calves and bedding material), to assess the presence of resistance, describe profiles, compare these resistances among groups.Material methodsSamples were collected calving pens 20 dairy farms. Using disc diffusion method, isolates screened for against seven antimicrobials: Amoxicillin, Ceftiofur, Gentamicin, Enrofloxacin,...
Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis worldwide. As reported in other countries, after rise and fall pandemic strain Chile, post-pandemic strains have been associated with clinical cases, including lacking major toxins TDH TRH. Since presence or absence tdh trh genes has used for diagnostic purposes as a proxy virulence V. isolates, understanding essential to detect these present water marine products avoid possible food-borne infection. In this study,...
The Type VI Secretion System (T6SS) is a multiprotein device that has emerged as an important fitness and virulence factor for many Gram-negative bacteria through the injection of effector proteins into prokaryotic or eukaryotic cells via contractile mechanism. While some specifically target bacterial cells, others can both types (trans-kingdom effectors). In Salmonella, five T6SS gene clusters have been identified within pathogenicity islands SPI-6, SPI-19, SPI-20, SPI-21, SPI-22, which are...
The type VI secretion system (T6SS) is a contact-dependent contractile multiprotein apparatus widely distributed in Gram-negative bacteria. These systems can deliver different effector proteins into target bacterial and/or eukaryotic cells, contributing to the environmental fitness and virulence of many pathogens. Salmonella harbors five T6SSs encoded genomic islands. T6SS Pathogenicity Island 6 (SPI-6) contributes competition with host microbiota its interaction infected cells. Despite...
is the leading cause of seafood-borne gastroenteritis worldwide. A distinctive feature O3:K6 pandemic clone, and its derivatives, presence a second, phylogenetically distinct, type III secretion system (T3SS2) encoded within genomic island VPaI-7. The T3SS2 allows delivery effector proteins directly into cytosol infected eukaryotic cells to subvert key host-cell processes, critical for
The invasion of Chlamydia trachomatis, an obligate intracellular bacterium, into epithelial cells is driven by a complex interplay host and bacterial factors. To comprehensively define the genes required for pathogen invasion, we undertook fluorescence-activated cell sorting (FACS)-based CRISPR screen in human cells. A genome-wide loss-of-function library was infected with fluorescent C. trachomatis then sorted to enrich invasion-deficient mutants. identified heparan sulfate, known receptor,...
Campylobacter is the leading cause of bacterial gastroenteritis worldwide and an emerging neglected pathogen in South America. This zoonotic colonizes gastrointestinal tract a wide range mammals birds, with poultry as most important reservoir for human infections. Apart from its high morbidity rates, emergence resistant strains global concern. The aims this work were to determine genetic diversity, presence antimicrobial resistance determinants virulence potential spp. isolated patients...
Vibrio parahaemolyticus non-toxigenic strains are responsible for about 10% of acute gastroenteritis associated with this species, suggesting they harbor unique virulence factors. Zonula occludens toxin (Zot), firstly described in cholerae, is a secreted that increases intestinal permeability. Recently, we identified Zot-encoding genes the genomes highly cytotoxic Chilean V. strains, including clinical strain PMC53.7. To gain insights into possible role Zot parahaemolyticus, analyzed whether...
Salmonella enterica serovar Enteritidis has emerged as a major health problem worldwide in the last few decades. DNA loci unique to S. can provide markers for detection of this pathogen and may reveal pathogenic mechanisms restricted serovar. An silico comparison 16 genomic sequences revealed presence an approximately 12.5-kb island (GEI) specific sequenced strain NCTC13349. The GEI is inserted at 5' end gene ydaO (SEN1377), flanked by 308-bp imperfect direct repeats (attL attR), includes 21...
Shigella flexneri 2a 2457T produces lipopolysaccharide (LPS) with two O-antigen (OAg) chain lengths: a short (S-OAg) controlled by WzzB and very long (VL-OAg) determined Wzz(pHS-2). This study demonstrates that the synthesis length distribution of S. OAg are under growth-phase-dependent regulation. Quantitative electrophoretic analysis showed VL-OAg increased during growth while S-OAg remained constant. Increased production correlated growth-phase-regulated expression transcription...