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León Y, Honigsberg R, Rasko DA, Faherty CS. Gastrointestinal signals in supplemented media reveal a role in adherence for the Shigella flexneri sap autotransporter gene. Gut Microbes 2024; 16:2331985. [PMID: 38549437 PMCID: PMC10984119 DOI: 10.1080/19490976.2024.2331985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 03/14/2024] [Indexed: 04/02/2024] Open
Abstract
Shigella flexneri causes severe diarrheal disease worldwide. While many aspects of pathogenesis have been elucidated, significant knowledge gaps remain regarding the role of putative chromosomally-encoded virulence genes. The uncharacterized sap gene encoded on the chromosome has significant nucleotide sequence identity to the fluffy (flu) antigen 43 autotransporter gene in pathogenic Escherichia coli. Here, we constructed a Δsap mutant in S. flexneri strain 2457T and examined the effects of this mutation on bacterial cell aggregation, biofilm formation, and adherence to colonic epithelial cells. Analyses included the use of growth media supplemented with glucose and bile salts to replicate small intestinal signals encountered by S. flexneri. Deletion of the sap gene in 2457T affected epithelial cell adherence, resulted in quicker bacterial cell aggregation, but did not affect biofilm formation. This work highlights a functional role for the sap gene in S. flexneri pathogenesis and further demonstrates the importance of using relevant and appropriate gastrointestinal signals to characterize virulence genes of enteropathogenic bacteria.
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Affiliation(s)
- Yrvin León
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Raphael Honigsberg
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- École Normale Supérieure Paris-Saclay, Département d’Enseignement et de, Recherche de Biologie, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David A. Rasko
- Institute for Genome Sciences, Center for Pathogen Research, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christina S. Faherty
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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2
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Abstract
Enteric bacterial infections contribute substantially to global disease burden and mortality, particularly in the developing world. In vitro 2D monolayer cultures have provided critical insights into the fundamental virulence mechanisms of a multitude of pathogens, including Salmonella enterica serovars Typhimurium and Typhi, Vibrio cholerae, Shigella spp., Escherichia coli and Campylobacter jejuni, which have led to the identification of novel targets for antimicrobial therapy and vaccines. In recent years, the arsenal of experimental systems to study intestinal infections has been expanded by a multitude of more complex models, which have allowed to evaluate the effects of additional physiological and biological parameters on infectivity. Organoids recapitulate the cellular complexity of the human intestinal epithelium while 3D bioengineered scaffolds and microphysiological devices allow to emulate oxygen gradients, flow and peristalsis, as well as the formation and maintenance of stable and physiologically relevant microbial diversity. Additionally, advancements in ex vivo cultures and intravital imaging have opened new possibilities to study the effects of enteric pathogens on fluid secretion, barrier integrity and immune cell surveillance in the intact intestine. This review aims to present a balanced and updated overview of current intestinal in vitro and ex vivo methods for modeling of enteric bacterial infections. We conclude that the different paradigms are complements rather than replacements and their combined use promises to further our understanding of host-microbe interactions and their impacts on intestinal health.
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Affiliation(s)
- Nayere Taebnia
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- CONTACT Ute Römling Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Volker M. Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
- University of Tübingen, Tübingen, Germany
- Volker M. Lauschke Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
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SepA Enhances Shigella Invasion of Epithelial Cells by Degrading Alpha-1 Antitrypsin and Producing a Neutrophil Chemoattractant. mBio 2021; 12:e0283321. [PMID: 34724811 PMCID: PMC8561385 DOI: 10.1128/mbio.02833-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Shigella spp. are highly adapted pathogens that cause bacillary dysentery in human and nonhuman primates. An unusual feature of Shigella pathogenesis is that this organism invades the colonic epithelia from the basolateral pole. Therefore, it has evolved the ability to disrupt the intestinal epithelial barrier to reach the basolateral surface. We have shown previously that the secreted serine protease A (SepA), which belongs to the family of serine protease autotransporters of Enterobacteriaceae, is responsible for the initial destabilization of the intestinal epithelial barrier that facilitates Shigella invasion. However, the mechanisms used by SepA to regulate this process remain unknown. To investigate the protein targets cleaved by SepA in the intestinal epithelium, we incubated a sample of homogenized human colon with purified SepA or with a catalytically inactive mutant of this protease. We discovered that SepA targets an array of 18 different proteins, including alpha-1 antitrypsin (AAT), a major circulating serine proteinase inhibitor in humans. In contrast to other serine proteases, SepA cleaved AAT without forming an inhibiting complex, which resulted in the generation of a neutrophil chemoattractant. We demonstrated that the products of the AAT-SepA reaction induce a mild but significant increase in neutrophil transepithelial migration in vitro. Moreover, the presence of AAT during Shigella infection stimulated neutrophil migration and dramatically enhanced the number of bacteria invading the intestinal epithelium in a SepA-dependent manner. We conclude that by cleaving AAT, SepA releases a chemoattractant that promotes neutrophil migration, which in turn disrupts the intestinal epithelial barrier to enable Shigella invasion. IMPORTANCE Shigella is the second leading cause of diarrheal death globally. In this study, we identified the host protein targets of SepA, Shigella's major protein secreted in culture. We demonstrated that by cleaving AAT, a serine protease inhibitor important to protect surrounding tissue at inflammatory sites, SepA releases a neutrophil chemoattractant that enhances Shigella invasion. Moreover, SepA degraded AAT without becoming inhibited by the cleaved product, and SepA catalytic activity was enhanced at higher concentrations of AAT. Activation of SepA by an excess of AAT may be physiologically relevant at the early stages of Shigella infection, when the amount of synthesized SepA is very low compared to the concentration of AAT in the intestinal lumen. This observation may also help to explain the adeptness of Shigella infectivity at low dose, despite the requirement of reaching the basolateral side to invade and colonize the colonic epithelium.
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Locke RK, Greig DR, Jenkins C, Dallman TJ, Cowley LA. Acquisition and loss of CTX-M plasmids in Shigella species associated with MSM transmission in the UK. Microb Genom 2021; 7. [PMID: 34427554 PMCID: PMC8549364 DOI: 10.1099/mgen.0.000644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shigellosis in men who have sex with men (MSM) is caused by multidrug resistant Shigellae, exhibiting resistance to antimicrobials including azithromycin, ciprofloxacin and more recently the third-generation cephalosporins. We sequenced four blaCTX-M-27-positive MSM Shigella isolates (2018–20) using Oxford Nanopore Technologies; three S. sonnei (identified as two MSM clade 2, one MSM clade 5) and one S. flexneri 3a, to explore AMR context. All S. sonnei isolates harboured Tn7/Int2 chromosomal integrons, whereas S. flexneri 3a contained the Shigella Resistance Locus. All strains harboured IncFII pKSR100-like plasmids (67-83kbp); where present blaCTX-M-27 was located on these plasmids flanked by IS26 and IS903B, however blaCTX-M-27 was lost in S. flexneri 3a during storage between Illumina and Nanopore sequencing. IncFII AMR regions were mosaic and likely reorganised by IS26; three of the four plasmids contained azithromycin-resistance genes erm(B) and mph(A) and one harboured the pKSR100 integron. Additionally, all S. sonnei isolates possessed a large IncB/O/K/Z plasmid, two of which carried aph(3’)-Ib/aph(6)-Id/sul2 and tet(A). Monitoring the transmission of mobile genetic elements with co-located AMR determinants is necessary to inform empirical treatment guidance and clinical management of MSM-associated shigellosis.
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Affiliation(s)
| | - David R Greig
- Gastrointestinal Reference Services, Public Health England, London, UK.,Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, EH25 9RG, UK
| | - Claire Jenkins
- Gastrointestinal Reference Services, Public Health England, London, UK
| | - Tim J Dallman
- Gastrointestinal Reference Services, Public Health England, London, UK.,Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, EH25 9RG, UK
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Arabshahi S, Novinrooz A, Ranjbar R, Imani Fooladi AA. Molecular characterization of Shigella species isolated from diarrheal patients in Tehran, Iran: phylogenetic typing and its association with virulence gene profiles and a novel description of Shigella invasion associated locus. Eur J Clin Microbiol Infect Dis 2020; 39:1727-1737. [PMID: 32350738 DOI: 10.1007/s10096-020-03908-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/13/2020] [Indexed: 10/23/2022]
Abstract
The present study aims to employ a multiplex PCR-based method for phylogenetic typing of Shigella and determine the frequency of several virulence genes among Shigella phylogenetic clades and species. Species identification, phylogenetic typing of 44 previously diagnosed Shigella isolates, and frequency of virulence genes and loci, virA, virB, virF, ipaBCD, ial, sen, and set1A were investigated through performing several PCR assays. Distribution of virulence genes among Shigella phylogenetic clades and species was determined by the statistical analysis. The identities of 40 isolates out of 44 were confirmed as Shigella, and these isolates were classified in four phylogenetic clades, S1 (7.5%), S2 (52.5%), S3 (20%), and S5 (20%) and 4 species, S. sonnei (52.5%), S. flexneri (22.5%), S. dysenteriae (20%), and S. boydii (5%). The prevalence of virA, virB, virF, ipaBCD, ial, sen, and set1A was determined as 67.5%, 72.5%, 72.5%, 65%, 75%, 40%, and 5%, respectively. The presence of sen, uidA, or set1A was found to be statistically correlated with either of Shigella phylogenetic clades or species. A significant statistically association was also determined between set1A and Shigella phylogenetic clades. Furthermore, the nucleotide sequence of invasion-associated locus (ial) was determined and mapped on Shigella genome through in silico analysis. The current study shows the distribution of Shigella isolates and its key virulence genes within the five recently described phylogenetic clades for the first time in the Asia. This is also the first description of ial nucleotide sequence and its exact location on Shigella genome after its initial identification.
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Affiliation(s)
- Sina Arabshahi
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Aytak Novinrooz
- Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Reza Ranjbar
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Abbas Ali Imani Fooladi
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Cervantes-Rivera R, Tronnet S, Puhar A. Complete genome sequence and annotation of the laboratory reference strain Shigella flexneri serotype 5a M90T and genome-wide transcriptional start site determination. BMC Genomics 2020; 21:285. [PMID: 32252626 PMCID: PMC7132871 DOI: 10.1186/s12864-020-6565-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 02/07/2020] [Indexed: 01/19/2023] Open
Abstract
Background Shigella is a Gram-negative facultative intracellular bacterium that causes bacillary dysentery in humans. Shigella invades cells of the colonic mucosa owing to its virulence plasmid-encoded Type 3 Secretion System (T3SS), and multiplies in the target cell cytosol. Although the laboratory reference strain S. flexneri serotype 5a M90T has been extensively used to understand the molecular mechanisms of pathogenesis, its complete genome sequence is not available, thereby greatly limiting studies employing high-throughput sequencing and systems biology approaches. Results We have sequenced, assembled, annotated and manually curated the full genome of S. flexneri 5a M90T. This yielded two complete circular contigs, the chromosome and the virulence plasmid (pWR100). To obtain the genome sequence, we have employed long-read PacBio DNA sequencing followed by polishing with Illumina RNA-seq data. This provides a new hybrid strategy to prepare gapless, highly accurate genome sequences, which also cover AT-rich tracks or repetitive sequences that are transcribed. Furthermore, we have performed genome-wide analysis of transcriptional start sites (TSS) and determined the length of 5′ untranslated regions (5′-UTRs) at typical culture conditions for the inoculum of in vitro infection experiments. We identified 6723 primary TSS (pTSS) and 7328 secondary TSS (sTSS). The S. flexneri 5a M90T annotated genome sequence and the transcriptional start sites are integrated into RegulonDB (http://regulondb.ccg.unam.mx) and RSAT (http://embnet.ccg.unam.mx/rsat/) databases to use their analysis tools in the S. flexneri 5a M90T genome. Conclusions We provide the first complete genome for S. flexneri serotype 5a, specifically the laboratory reference strain M90T. Our work opens the possibility of employing S. flexneri M90T in high-quality systems biology studies such as transcriptomic and differential expression analyses or in genome evolution studies. Moreover, the catalogue of TSS that we report here can be used in molecular pathogenesis studies as a resource to know which genes are transcribed before infection of host cells. The genome sequence, together with the analysis of transcriptional start sites, is also a valuable tool for precise genetic manipulation of S. flexneri 5a M90T. Further, we present a new hybrid strategy to prepare gapless, highly accurate genome sequences. Unlike currently used hybrid strategies combining long- and short-read DNA sequencing technologies to maximize accuracy, our workflow using long-read DNA sequencing and short-read RNA sequencing provides the added value of using non-redundant technologies, which yield distinct, exploitable datasets.
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Affiliation(s)
- Ramón Cervantes-Rivera
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Sophie Tronnet
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden.,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden.,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Andrea Puhar
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), 901 87 Umeå, Sweden. .,Umeå Centre for Microbial Research (UCMR), 901 87, Umeå, Sweden. .,Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden.
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7
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8
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Bacteriophage Therapy Testing Against Shigella flexneri in a Novel Human Intestinal Organoid-Derived Infection Model. J Pediatr Gastroenterol Nutr 2019; 68:509-516. [PMID: 30418409 PMCID: PMC6939622 DOI: 10.1097/mpg.0000000000002203] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Enteric bacterial pathogens cause diarrheal disease and mortality at significant rates throughout the world, particularly in children younger than 5 years. Our ability to combat bacterial pathogens has been hindered by antibiotic resistance, a lack of effective vaccines, and accurate models of infection. With the renewed interest in bacteriophage therapy, we sought to use a novel human intestinal model to investigate the efficacy of a newly isolated bacteriophage against Shigella flexneri. METHODS An S. flexneri 2457T-specific bacteriophage was isolated and assessed through kill curve experiments and infection assays with colorectal adenocarcinoma HT-29 cells and a novel human intestinal organoid-derived epithelial monolayer model. In our treatment protocol, organoids were generated from intestinal crypt stem cells, expanded in culture, and seeded onto transwells to establish 2-dimensional monolayers that differentiate into intestinal cells. RESULTS The isolated bacteriophage efficiently killed S. flexneri 2457T, other S. flexneri strains, and a strain of 2457T harboring an antibiotic resistance cassette. Analyses with laboratory and commensal Escherichia coli strains demonstrated that the bacteriophage was specific to S. flexneri, as observed under co-culture conditions. Importantly, the bacteriophage prevented both S. flexneri 2457T epithelial cell adherence and invasion in both infection models. CONCLUSIONS Bacteriophages offer feasible alternatives to antibiotics for eliminating enteric pathogens, confirmed here by the bacteriophage-targeted killing of S. flexneri. Furthermore, application of the organoid model has provided important insight into Shigella pathogenesis and bacteriophage-dependent intervention strategies. The screening platform described herein provides proof-of-concept analysis for the development of novel bacteriophage therapies to target antibiotic-resistant pathogens.
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9
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Mannion AJ, Martin HR, Shen Z, Buckley EM, Dzink-Fox JL, Garcia A, Marini RP, Patterson MM, Fox JG. Plasmid-Mediated Quinolone Resistance in Shigella flexneri Isolated From Macaques. Front Microbiol 2018; 9:311. [PMID: 29556221 PMCID: PMC5844971 DOI: 10.3389/fmicb.2018.00311] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/09/2018] [Indexed: 12/02/2022] Open
Abstract
Non-human primates (NHPs) for biomedical research are commonly infected with Shigella spp. that can cause acute dysentery or chronic episodic diarrhea. These animals are often prophylactically and clinically treated with quinolone antibiotics to eradicate these possible infections. However, chromosomally- and plasmid-mediated antibiotic resistance has become an emerging concern for species in the family Enterobacteriaceae. In this study, five individual isolates of multi-drug resistant Shigella flexneri were isolated from the feces of three macaques. Antibiotic susceptibility testing confirmed resistance or decreased susceptibility to ampicillin, amoxicillin-clavulanic acid, cephalosporins, gentamicin, tetracycline, ciprofloxacin, enrofloxacin, levofloxacin, and nalidixic acid. S. flexneri isolates were susceptible to trimethoprim-sulfamethoxazole, and this drug was used to eradicate infection in two of the macaques. Plasmid DNA from all isolates was positive for the plasmid-encoded quinolone resistance gene qnrS, but not qnrA and qnrB. Conjugation and transformation of plasmid DNA from several S. flexneri isolates into antibiotic-susceptible Escherichia coli strains conferred the recipients with resistance or decreased susceptibility to quinolones and beta-lactams. Genome sequencing of two representative S. flexneri isolates identified the qnrS gene on a plasmid-like contig. These contigs showed >99% homology to plasmid sequences previously characterized from quinolone-resistant Shigella flexneri 2a and Salmonella enterica strains. Other antibiotic resistance genes and virulence factor genes were also identified in chromosome and plasmid sequences in these genomes. The findings from this study indicate macaques harbor pathogenic S. flexneri strains with chromosomally- and plasmid-encoded antibiotic resistance genes. To our knowledge, this is the first report of plasmid-mediated quinolone resistance in S. flexneri isolated from NHPs and warrants isolation and antibiotic testing of enteric pathogens before treating macaques with quinolones prophylactically or therapeutically.
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Affiliation(s)
- Anthony J Mannion
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Heather R Martin
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Zeli Shen
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Ellen M Buckley
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - JoAnn L Dzink-Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Alexis Garcia
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Robert P Marini
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mary M Patterson
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - James G Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States
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Kotloff KL, Riddle MS, Platts-Mills JA, Pavlinac P, Zaidi AKM. Shigellosis. Lancet 2018; 391:801-812. [PMID: 29254859 DOI: 10.1016/s0140-6736(17)33296-8] [Citation(s) in RCA: 307] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/10/2017] [Accepted: 09/15/2017] [Indexed: 01/02/2023]
Abstract
Shigellosis is a clinical syndrome caused by invasion of the epithelium lining the terminal ileum, colon, and rectum by Shigella species. Although infections occur globally, and in people of all ages, endemic infections among children aged 1-4 years living in low-income and middle-income settings constitute most of the disease burden. The versatile manifestations of these highly contagious organisms range from acute watery diarrhoea to fulminant dysentery characterised by frequent scant bloody stools with fever, prostration, and abdominal cramps. A broad array of uncommon, but often severe, intestinal and extraintestinal complications can occur. Despite marked reductions in mortality during the past three decades, there are roughly 164 000 annual deaths attributable to shigellosis. Intercontinental dissemination of multiresistant shigella strains, facilitated by travellers and men who have sex with men, has prompted new recommendations for antibiotic therapy. Awareness of disease burden and the emerging threats posed by shigella have accelerated interest in development of shigella vaccines, many of which are being tested in clinical trials.
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Affiliation(s)
- Karen L Kotloff
- Departments of Pediatrics and Medicine, Center for Vaccine Development, Institute for Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Mark S Riddle
- Naval Medical Research Center, Silver Spring, MD, USA; Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - James A Platts-Mills
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Patricia Pavlinac
- Department of Global Health, Global Center for Integrated Health of Women, Adolescents and Children (Global WACh), University of Washington, Seattle, WA, USA
| | - Anita K M Zaidi
- Enteric and Diarrheal Diseases Programme, Bill & Melinda Gates Foundation, Seattle, WA, USA
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Medeiros PHQS, Lima AÂM, Guedes MM, Havt A, Bona MD, Rey LC, Soares AM, Guerrant RL, Weigl BH, Lima IFN. Molecular characterization of virulence and antimicrobial resistance profile of Shigella species isolated from children with moderate to severe diarrhea in northeastern Brazil. Diagn Microbiol Infect Dis 2017; 90:198-205. [PMID: 29217418 DOI: 10.1016/j.diagmicrobio.2017.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/08/2017] [Accepted: 11/01/2017] [Indexed: 12/28/2022]
Abstract
Molecular characterization of virulence and antimicrobial resistance profiles were determined for Shigella species isolated from children with diarrhea in Fortaleza, Brazil. Fecal specimens were collected along with socioeconomic and clinical data from children with moderate to severe diarrhea requiring emergency care. Shigella spp. were isolated by standard microbiological techniques, and we developed 4 multiplex polymerase chain reaction assays to detect 16 virulence-related genes (VRGs). Antimicrobial susceptibility tests were performed using disk diffusion assays. S. flexneri and S. sonnei were the predominant serogroups. S. flexneri was associated with low monthly incomes; more severe disease; higher number of VRGs; and presence of pic, set, and sepA genes. The SepA gene was associated with more intense abdominal pain. S. flexneri was correlated with resistance to ampicillin and chloramphenicol, whereas S. sonnei was associated with resistance to azithromycin. Strains harboring higher numbers of VRGs were associated with resistance to more antimicrobials. We highlight the correlation between presence of S. flexneri and sepA, and increased virulence and suggest a link to socioeconomic change in northeastern Brazil. Additionally, antimicrobial resistance was associated with serogroup specificity in Shigella spp. and increased bacterial VRGs.
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Affiliation(s)
| | - Aldo Ângelo Moreira Lima
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil; Center for Global Health, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Marjorie Moreira Guedes
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Alexandre Havt
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Mariana Duarte Bona
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Luís Carlos Rey
- Department of Mother and Child Health, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Alberto Melo Soares
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil
| | - Richard Littleton Guerrant
- Center for Global Health, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Bernhard H Weigl
- Program for Appropriate Technology in Health (PATH), Seattle, WA, USA
| | - Ila Fernanda Nunes Lima
- Institute of Biomedicine for Brazilian Semi-Arid (IBISAB), Department of Physiology and Pharmacology, Federal University of Ceara, Fortaleza, CE, Brazil
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Mattock E, Blocker AJ. How Do the Virulence Factors of Shigella Work Together to Cause Disease? Front Cell Infect Microbiol 2017; 7:64. [PMID: 28393050 PMCID: PMC5364150 DOI: 10.3389/fcimb.2017.00064] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/21/2017] [Indexed: 01/01/2023] Open
Abstract
Shigella is the major cause of bacillary dysentery world-wide. It is divided into four species, named S. flexneri, S. sonnei, S. dysenteriae, and S. boydii, which are distinct genomically and in their ability to cause disease. Shigellosis, the clinical presentation of Shigella infection, is characterized by watery diarrhea, abdominal cramps, and fever. Shigella's ability to cause disease has been attributed to virulence factors, which are encoded on chromosomal pathogenicity islands and the virulence plasmid. However, information on these virulence factors is not often brought together to create a detailed picture of infection, and how this translates into shigellosis symptoms. Firstly, Shigella secretes virulence factors that induce severe inflammation and mediate enterotoxic effects on the colon, producing the classic watery diarrhea seen early in infection. Secondly, Shigella injects virulence effectors into epithelial cells via its Type III Secretion System to subvert the host cell structure and function. This allows invasion of epithelial cells, establishing a replicative niche, and causes erratic destruction of the colonic epithelium. Thirdly, Shigella produces effectors to down-regulate inflammation and the innate immune response. This promotes infection and limits the adaptive immune response, causing the host to remain partially susceptible to re-infection. Combinations of these virulence factors may contribute to the different symptoms and infection capabilities of the diverse Shigella species, in addition to distinct transmission patterns. Further investigation of the dominant species causing disease, using whole-genome sequencing and genotyping, will allow comparison and identification of crucial virulence factors and may contribute to the production of a pan-Shigella vaccine.
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Affiliation(s)
- Emily Mattock
- Faculty of Biomedical Sciences, Schools of Cellular and Molecular Medicine and Biochemistry, University of Bristol Bristol, UK
| | - Ariel J Blocker
- Faculty of Biomedical Sciences, Schools of Cellular and Molecular Medicine and Biochemistry, University of Bristol Bristol, UK
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Faherty CS, Wu T, Morris CR, Grassel CL, Rasko DA, Harper JM, Shea-Donohue T, Fasano A, Barry EM. The synthesis of OspD3 (ShET2) in Shigella flexneri is independent of OspC1. Gut Microbes 2016; 7:486-502. [PMID: 27657187 PMCID: PMC5103656 DOI: 10.1080/19490976.2016.1239682] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shigella flexneri is a Gram-negative pathogen that invades the colonic epithelium and causes millions of cases of watery diarrhea or bacillary dysentery predominately in children under the age of 5 years in developing countries. The effector Shigella enterotoxin 2 (ShET2), or OspD3, is encoded by the sen or ospD3 gene on the virulence plasmid. Previous literature has suggested that ospD3 is in an operon downstream of the ospC1 gene, and expression of both genes is controlled by a promoter upstream of ospC1. Since the intergenic region is 328 bases in length and contains several putative promoter regions, we hypothesized the genes are independently expressed. Here we provide data that ospD3 and ospC1 are not co-transcribed and that OspC1 is not required for OspD3/ShET2 function. Most importantly, we identified strong promoter activity in the intergenic region and demonstrate that OspD3/ShET2 can be expressed and secreted independently of OspC1. This work increases our understanding of the synthesis of a unique virulence factor and provides further insights into Shigella pathogenesis.
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Affiliation(s)
- Christina S. Faherty
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland,Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, Massachusetts,CONTACT Christina S. Faherty Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, 114 16th Street (114-3503), Charlestown, MA, 02129
| | - Tao Wu
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland
| | - Carolyn R. Morris
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland,Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Christen L. Grassel
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland
| | - David A. Rasko
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jill M. Harper
- Department of Medicine, Mucosal Biology Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Terez Shea-Donohue
- Department of Medicine, Mucosal Biology Research Center, University of Maryland School of Medicine, Baltimore, Maryland
| | - Alessio Fasano
- Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Eileen M. Barry
- Department of Medicine, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland
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14
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Seribelli AA, Frazão MR, Medeiros MIC, Falcão JP. Molecular and phenotypic characterization of strains of Shigella sonnei isolated over 31 years suggests the circulation of two prevalent subtypes in São Paulo State, Brazil. J Med Microbiol 2016; 65:666-677. [PMID: 27267912 DOI: 10.1099/jmm.0.000290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Shigella sonnei is an important causative agent of bacillary dysentery worldwide that has recently emerged in developing countries. However, there are few studies that have characterized strains ofS. sonnei isolated in Brazil. The aims of this study were to assess the presence of 12 virulence genes, the antimicrobial resistance profile against 16 drugs and the genotypic diversity of strains of S. sonnei isolated in this country. Seventy-two strains of S. sonnei isolated from human diarrhoeic faeces in São Paulo State, Brazil from 1983-2014 were studied. All of the strains contained the ipaH, iuc and sigA genes. The ipaBCD gene was detected in 19 % of the strains, the ial and virF genes in 18 % and the sen gene in 10 % of the strains. The set1A, set1B, pic,sepA and sat genes were not detected. A total of 42 (58.3 %) strains were resistant to trimethoprim-sulfamethoxazole. Thirty (41.6 %) strains were resistant to tetracycline. The S. sonnei strains were grouped in two clusters called A and B by PFGE and ERIC-PCR, and the majority of the strains comprised in each cluster presented ≥80 % similarity. In conclusion, the pathogenic potential of the strains studied was highlighted by the presence of important virulence genes. The high rates of resistance to trimethoprim-sulfamethoxazole and tetracycline are alarming once those drugs can be used in the treatment of shigellosis. The PFGE and ERIC-PCR results suggest that there are two prevalent subtypes in the studied strains of S. sonnei that differed little over 31 years and have been contaminating humans and causing diseases in São Paulo State, Brazil.
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Affiliation(s)
- Amanda Ap Seribelli
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Miliane R Frazão
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Juliana P Falcão
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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15
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The HC, Thanh DP, Holt KE, Thomson NR, Baker S. The genomic signatures of Shigella evolution, adaptation and geographical spread. Nat Rev Microbiol 2016; 14:235-50. [PMID: 26923111 DOI: 10.1038/nrmicro.2016.10] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Shigella spp. are some of the key pathogens responsible for the global burden of diarrhoeal disease. These facultative intracellular bacteria belong to the family Enterobacteriaceae, together with other intestinal pathogens, such as Escherichia coli and Salmonella spp. The genus Shigella comprises four different species, each consisting of several serogroups, all of which show phenotypic similarity, including invasive pathogenicity. DNA sequencing suggests that this similarity results from the convergent evolution of different Shigella spp. founders. Here, we review the evolutionary relationships between Shigella spp. and E . coli, and we highlight how the genomic plasticity of these bacteria and their acquisition of a distinctive virulence plasmid have enabled the development of such highly specialized pathogens. Furthermore, we discuss the insights that genotyping and whole-genome sequencing have provided into the phylogenetics and intercontinental spread of Shigella spp.
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Affiliation(s)
- Hao Chung The
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam
| | - Kathryn E Holt
- Centre for Systems Genomics, University of Melbourne.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Nicholas R Thomson
- Bacterial Genomics, The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.,Centre for Tropical Medicine and Global Health, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, UK.,Department of Pathogen and Molecular Biology, The London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK
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16
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Butler J. Collection, Handling, and Analysis of Specimens for Studies of Mucosal Immunity in Animals of Veterinary Importance. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.15003-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Fiorentino M, Levine MM, Sztein MB, Fasano A. Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release. PLoS One 2014; 9:e85211. [PMID: 24416363 PMCID: PMC3887025 DOI: 10.1371/journal.pone.0085211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/27/2013] [Indexed: 01/22/2023] Open
Abstract
Bacterial dysentery due to Shigella species is a major cause of morbidity and mortality worldwide. The pathogenesis of Shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. Although the mechanisms of pathogenesis of Shigella in the colon have been extensively studied, little is known on the effect of wild-type Shigella on the small intestine and the role of the host response in the development of the disease. Moreover, to the best of our knowledge no studies have described the effects of apically administered Shigella flexneri 2a and S. dysenteriae 1 vaccine strains on human small intestinal enterocytes. The aim of this study was to assess the coordinated functional and immunological human epithelial responses evoked by strains of Shigella and candidate vaccines on small intestinal enterocytes. To model the interactions of Shigella with the intestinal mucosa, we apically exposed monolayers of human intestinal Caco2 cells to increasing bacterial inocula. We monitored changes in paracellular permeability, examined the organization of tight-junctions and the pro-inflammatory response of epithelial cells. Shigella infection of Caco2 monolayers caused severe mucosal damage, apparent as a drastic increase in paracellular permeability and disruption of tight junctions at the cell-cell boundary. Secretion of pro-inflammatory IL-8 was independent of epithelial barrier dysfunction. Shigella vaccine strains elicited a pro-inflammatory response without affecting the intestinal barrier integrity. Our data show that wild-type Shigella infection causes a severe alteration of the barrier function of a small intestinal cell monolayer (a proxy for mucosa) and might contribute (along with enterotoxins) to the induction of watery diarrhea. Diarrhea may be a mechanism by which the host attempts to eliminate harmful bacteria and transport them from the small to the large intestine where they invade colonocytes inducing a strong inflammatory response.
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Affiliation(s)
- Maria Fiorentino
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Myron M. Levine
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Marcelo B. Sztein
- Center for Vaccine Development and the Departments of Pediatrics and Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
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18
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Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 829] [Impact Index Per Article: 75.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
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Abstract
Renewed awareness of the substantial morbidity and mortality that Shigella infection causes among young children in developing countries, combined with technological innovations in vaccinology, has led to the development of novel vaccine strategies in the past 5 years. Along with advancement of classic vaccines in clinical trials and new sophisticated measurements of immunological responses, much new data has been produced, lending promise to the potential for production of safe and effective Shigella vaccines. Herein, we review the latest progress in Shigella vaccine development within the framework of persistent obstacles.
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20
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Helicobacter pylori-induced disruption of monolayer permeability and proinflammatory cytokine secretion in polarized human gastric epithelial cells. Infect Immun 2013; 81:876-83. [PMID: 23297384 DOI: 10.1128/iai.01406-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Helicobacter pylori infection of the stomach is related to the development of diverse gastric pathologies. The ability of H. pylori to compromise epithelial junctional complexes and to induce proinflammatory cytokines is believed to contribute to pathogenesis. The purpose of this study was to use an in vitro human gastric epithelial model to investigate the ability of H. pylori to affect permeability and the extent and polarity of the host inflammatory response. NCI-N87 monolayers were cocultured with live or heat-killed H. pylori or culture supernatants. Epithelial barrier function was measured by transepithelial electric resistance (TEER) analysis, diffusion of fluorescein isothiocyanate (FITC)-labeled markers, and immunostaining for tight junction proteins. Supernatants from both apical and basolateral chambers were tested for cytokine production by multiplex analysis. H. pylori caused a significant decrease in TEER, an increased passage of markers through the infected monolayer, and severe disruption and mislocalization of ZO-1 and claudin-1 proteins. Cell viability was not altered by H. pylori, indicating that loss of barrier function could be attributed to a breakdown of tight junction integrity. Significantly high levels of cytokine secretion were induced by either viable or heat-killed H. pylori. H. pylori affects monolayer permeability of polarized human gastric epithelial cells. Proinflammatory cytokines were secreted in a polarized manner, mostly basolaterally. Live bacteria are required for disruption of tight junctions but not for the induction of cytokine secretion. The NCI-N87 cell line provides an excellent model for the in vitro study of H. pylori pathogenesis and the epithelial cell host response to infection.
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