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Arroyo-Mendoza M, Proctor A, Correa-Medina A, DeWolf S, Brand MW, Rosas V, Lorenzi H, Wannemuehler MJ, Phillips GJ, Hinton DM. A single rare σ70 variant establishes a unique gene expression pattern in the E. coli pathobiont LF82. Nucleic Acids Res 2024:gkae773. [PMID: 39258538 DOI: 10.1093/nar/gkae773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 08/08/2024] [Accepted: 08/28/2024] [Indexed: 09/12/2024] Open
Abstract
LF82, an adherent-invasive Escherichia coli (AIEC) pathobiont, is associated with Crohn's disease, an inflammatory bowel disease of unknown etiology. Although AIEC phenotypes differ from those of 'commensal' or pathogenic E. coli, work has failed to identify genetic features accounting for these differences. We have investigated a natural, but rare, single nucleotide polymorphism (SNP) in LF82 present within the highly conserved rpoD gene, encoding σ70 [primary sigma factor, RNA polymerase (RNAP)]. We demonstrate that σ70 D445V results in transcriptomic and phenotypic changes consistent with LF82 phenotypes, including increased antibiotic resistance and biofilm formation and increased capacity for methionine biosynthesis. RNA-seq analyses comparing σ70 V445 versus σ70 D445 identified 24 genes upregulated by σ70 V445 in both LF82 and the laboratory E. coli K-12 strain MG1655. Using in vitro transcription, we demonstrate that σ70 D445V directly increases transcription from promoters for several of the up-regulated genes and that the presence of a 16 bp spacer and -14 G:C is associated with this increase. The position of D445V within RNAP suggests that it could affect RNAP/spacer interaction. Our work represents the first identification of a distinguishing SNP for this pathobiont and suggests an underrecognized mechanism by which pathobionts and strain variants can emerge.
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Affiliation(s)
- Melissa Arroyo-Mendoza
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, USA
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Alexandra Proctor
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Abraham Correa-Medina
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, USA
| | - Sarah DeWolf
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Meghan Wymore Brand
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Virginia Rosas
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, USA
| | - Hernan Lorenzi
- TriLab Bioinformatics Group, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, USA
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Gregory J Phillips
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, USA
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Hinz A, Amado A, Kassen R, Bank C, Wong A. Unpredictability of the Fitness Effects of Antimicrobial Resistance Mutations Across Environments in Escherichia coli. Mol Biol Evol 2024; 41:msae086. [PMID: 38709811 PMCID: PMC11110942 DOI: 10.1093/molbev/msae086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 04/11/2024] [Accepted: 04/30/2024] [Indexed: 05/08/2024] Open
Abstract
The evolution of antimicrobial resistance (AMR) in bacteria is a major public health concern, and antibiotic restriction is often implemented to reduce the spread of resistance. These measures rely on the existence of deleterious fitness effects (i.e. costs) imposed by AMR mutations during growth in the absence of antibiotics. According to this assumption, resistant strains will be outcompeted by susceptible strains that do not pay the cost during the period of restriction. The fitness effects of AMR mutations are generally studied in laboratory reference strains grown in standard growth environments; however, the genetic and environmental context can influence the magnitude and direction of a mutation's fitness effects. In this study, we measure how three sources of variation impact the fitness effects of Escherichia coli AMR mutations: the type of resistance mutation, the genetic background of the host, and the growth environment. We demonstrate that while AMR mutations are generally costly in antibiotic-free environments, their fitness effects vary widely and depend on complex interactions between the mutation, genetic background, and environment. We test the ability of the Rough Mount Fuji fitness landscape model to reproduce the empirical data in simulation. We identify model parameters that reasonably capture the variation in fitness effects due to genetic variation. However, the model fails to accommodate the observed variation when considering multiple growth environments. Overall, this study reveals a wealth of variation in the fitness effects of resistance mutations owing to genetic background and environmental conditions, which will ultimately impact their persistence in natural populations.
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Affiliation(s)
- Aaron Hinz
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - André Amado
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
- Division of Theoretical Ecology and Evolution, Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Evolutionary Dynamics Group, Gulbenkian Science Institute, Oeiras, Portugal
| | - Rees Kassen
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Claudia Bank
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
- Division of Theoretical Ecology and Evolution, Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Evolutionary Dynamics Group, Gulbenkian Science Institute, Oeiras, Portugal
| | - Alex Wong
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
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3
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Pascal SB, Lorenzo R, Farías MVN, Rossen JW, Lucchesi PMA, Krüger A. Characterization of the flanking region of the Shiga toxin operon in Stx2a bacteriophages reveals a diversity of the NanS-p sialate O-acetylesterase gene. AIMS Microbiol 2023; 9:570-590. [PMID: 37649799 PMCID: PMC10462455 DOI: 10.3934/microbiol.2023030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 09/01/2023] Open
Abstract
Shiga toxin-producing E. coli (STEC) are diarrheagenic strains that can cause bloody diarrhea and hemolytic-uremic syndrome. Their main virulence factor, the Shiga toxin (Stx), is encoded by phages integrated into the bacterial chromosome. Stx phages are widely diverse and carry many genes with limited or unknown function. As the toxin subtype Stx2a is associated with highly pathogenic strains, this study was mainly focused on the characterization of the stx flanking region of Stx2a phages. Of particular interest was a sialate O-acetylesterase (NanS-p), which has been described previously to be encoded downstream stx in some phage genomes and may confer a growth advantage for STEC. Complete DNA sequences of Stx2a phages and prophages were retrieved from the GenBank database, and the genomic regions from anti-terminator Q to holin S genes were bioinformatically analyzed. Predicted NanSp sequences from phages encoding other Stx subtypes were also studied. Additionally, expression of nanS-p was quantified by qPCR in strains selected from our laboratory collection. The analysis of Stx2a phage genomes showed that all carried the Q, stx2a, nanS-p and S genes, but with allele diversity and other sequence differences. In particular, sequence differences were detected in each of the three domains of NanS-p esterases encoded by Stx2a phages and other Stx phages; however, nanS-p was not identified in the Stx2e, Stx2f and Stx2g phages analyzed. The expression of nanS-p increased in most stx2a-positive strains under phage inducing conditions, as was previously shown for stx2a. As the present work showed diversity at the Q-S region among Stx phages, and particularly in the encoded NanS-p enzyme, future studies will be necessary to evaluate if NanS-p variants differ in their activity and to assess the impact of the absence of nanS-p in certain Stx phages.
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Affiliation(s)
- Stefanía B. Pascal
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - Ramiro Lorenzo
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
- Laboratory of Neurophysiology, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - María Victoria Nieto Farías
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - John W.A. Rossen
- Laboratory of Medical Microbiology and Infectious Diseases, Isala Hospital, Zwolle, The Netherlands
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Paula M. A. Lucchesi
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
| | - Alejandra Krüger
- Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Facultad de Ciencias Veterinarias, CISAPA, Tandil, Buenos Aires, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA-CICPBA-CONICET, Tandil, Buenos Aires, Argentina
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4
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Arroyo-Mendoza M, Proctor A, Correa-Medina A, Brand MW, Rosas V, Wannemuehler MJ, Phillips GJ, Hinton DM. The E. coli pathobiont LF82 encodes a unique variant of σ 70 that results in specific gene expression changes and altered phenotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.08.523653. [PMID: 36798310 PMCID: PMC9934711 DOI: 10.1101/2023.02.08.523653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
LF82, an adherent invasive Escherichia coli pathobiont, is associated with ileal Crohn's disease, an inflammatory bowel disease of unknown etiology. Although LF82 contains no virulence genes, it carries several genetic differences, including single nucleotide polymorphisms (SNPs), that distinguish it from nonpathogenic E. coli. We have identified and investigated an extremely rare SNP that is within the highly conserved rpoD gene, encoding σ70, the primary sigma factor for RNA polymerase. We demonstrate that this single residue change (D445V) results in specific transcriptome and phenotypic changes that are consistent with multiple phenotypes observed in LF82, including increased antibiotic resistance and biofilm formation, modulation of motility, and increased capacity for methionine biosynthesis. Our work demonstrates that a single residue change within the bacterial primary sigma factor can lead to multiple alterations in gene expression and phenotypic changes, suggesting an underrecognized mechanism by which pathobionts and other strain variants with new phenotypes can emerge.
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Affiliation(s)
- Melissa Arroyo-Mendoza
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, United States, 20892
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States, 50011
| | - Alexandra Proctor
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States, 50011
| | - Abraham Correa-Medina
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, United States, 20892
| | - Meghan Wymore Brand
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States, 50011
| | - Virginia Rosas
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, United States, 20892
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States, 50011
| | - Gregory J Phillips
- Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States, 50011
| | - Deborah M Hinton
- Gene Expression and Regulation Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Dr., Bethesda, MD, United States, 20892
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5
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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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6
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Choudhary MI, Römling U, Nadeem F, Bilal HM, Zafar M, Jahan H, ur-Rahman A. Innovative Strategies to Overcome Antimicrobial Resistance and Tolerance. Microorganisms 2022; 11:microorganisms11010016. [PMID: 36677308 PMCID: PMC9863313 DOI: 10.3390/microorganisms11010016] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Antimicrobial resistance and tolerance are natural phenomena that arose due to evolutionary adaptation of microorganisms against various xenobiotic agents. These adaptation mechanisms make the current treatment options challenging as it is increasingly difficult to treat a broad range of infections, associated biofilm formation, intracellular and host adapted microbes, as well as persister cells and microbes in protected niches. Therefore, novel strategies are needed to identify the most promising drug targets to overcome the existing hurdles in the treatment of infectious diseases. Furthermore, discovery of novel drug candidates is also much needed, as few novel antimicrobial drugs have been introduced in the last two decades. In this review, we focus on the strategies that may help in the development of innovative small molecules which can interfere with microbial resistance mechanisms. We also highlight the recent advances in optimization of growth media which mimic host conditions and genome scale molecular analyses of microbial response against antimicrobial agents. Furthermore, we discuss the identification of antibiofilm molecules and their mechanisms of action in the light of the distinct physiology and metabolism of biofilm cells. This review thus provides the most recent advances in host mimicking growth media for effective drug discovery and development of antimicrobial and antibiofilm agents.
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Affiliation(s)
- M. Iqbal Choudhary
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 65 Stockholm, Sweden
- Correspondence: (U.R.); (H.J.); Tel.: +46-8-5248-7319 (U.R.); +92-21-111-232-292 (ext. 301) (H.J.)
| | - Faiza Nadeem
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Hafiz Muhammad Bilal
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Munirah Zafar
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
| | - Humera Jahan
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
- Correspondence: (U.R.); (H.J.); Tel.: +46-8-5248-7319 (U.R.); +92-21-111-232-292 (ext. 301) (H.J.)
| | - Atta ur-Rahman
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
- H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
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7
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Simulated Colonic Fluid Replicates the In Vivo Growth Capabilities of Citrobacter rodentium cpxRA Mutants and Uncovers Additive Effects of Cpx-Regulated Genes on Fitness. Infect Immun 2022; 90:e0031422. [PMID: 36000875 PMCID: PMC9476912 DOI: 10.1128/iai.00314-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Citrobacter rodentium is an attaching and effacing (A/E) pathogen used to model enteropathogenic and enterohemorrhagic Escherichia coli infections in mice. During colonization, C. rodentium must adapt to stresses in the gastrointestinal tract, such as antimicrobial peptides, pH changes, and bile salts. The Cpx envelope stress response (ESR) is a two-component system used by some bacteria to remediate stress by modulating gene expression, and it is necessary for C. rodentium pathogenesis in mice. Here, we utilized simulated colonic fluid (SCF) to mimic the gastrointestinal environment, which we show strongly induces the Cpx ESR and highlights a fitness defect specific to the ΔcpxRA mutant. While investigating genes in the Cpx regulon that may contribute to C. rodentium pathogenesis, we found that the absence of the Cpx ESR resulted in higher expression of the locus of enterocyte effacement (LEE) master regulator, ler, and that the genes yebE, ygiB, bssR, and htpX relied on CpxRA for proper expression. We then determined that CpxRA and select gene mutants were essential for proper growth in SCF when in the presence of extraneous stressors and in competition. Although none of the Cpx-regulated gene mutants exhibited marked virulence phenotypes in vivo, the ΔcpxRA mutant had reduced colonization and attenuated virulence, as previously determined, which replicated the in vitro growth phenotypes specific to SCF. Overall, these results indicate that the ΔcpxRA virulence defect is not due to any single Cpx regulon gene examined. Instead, attenuation may be the result of defective growth in the colonic environment resulting from the collective impact of multiple Cpx-regulated genes.
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8
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Glover G, Voliotis M, Łapińska U, Invergo BM, Soanes D, O'Neill P, Moore K, Nikolic N, Petrov PG, Milner DS, Roy S, Heesom K, Richards TA, Tsaneva-Atanasova K, Pagliara S. Nutrient and salt depletion synergistically boosts glucose metabolism in individual Escherichia coli cells. Commun Biol 2022; 5:385. [PMID: 35444215 PMCID: PMC9021252 DOI: 10.1038/s42003-022-03336-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/30/2022] [Indexed: 12/16/2022] Open
Abstract
The interaction between a cell and its environment shapes fundamental intracellular processes such as cellular metabolism. In most cases growth rate is treated as a proximal metric for understanding the cellular metabolic status. However, changes in growth rate might not reflect metabolic variations in individuals responding to environmental fluctuations. Here we use single-cell microfluidics-microscopy combined with transcriptomics, proteomics and mathematical modelling to quantify the accumulation of glucose within Escherichia coli cells. In contrast to the current consensus, we reveal that environmental conditions which are comparatively unfavourable for growth, where both nutrients and salinity are depleted, increase glucose accumulation rates in individual bacteria and population subsets. We find that these changes in metabolic function are underpinned by variations at the translational and posttranslational level but not at the transcriptional level and are not dictated by changes in cell size. The metabolic response-characteristics identified greatly advance our fundamental understanding of the interactions between bacteria and their environment and have important ramifications when investigating cellular processes where salinity plays an important role.
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Affiliation(s)
- Georgina Glover
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - Margaritis Voliotis
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Mathematics, University of Exeter, Stocker Road, Exeter, UK
| | - Urszula Łapińska
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Brandon M Invergo
- Translational Research Exchange at Exeter, University of Exeter, Exeter, UK
| | - Darren Soanes
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Paul O'Neill
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Karen Moore
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Nela Nikolic
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - Peter G Petrov
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - David S Milner
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Sumita Roy
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Kate Heesom
- University of Bristol Proteomics Facility, University Walk, Bristol, BS8 1TD, UK
| | - Thomas A Richards
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Krasimira Tsaneva-Atanasova
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Mathematics, University of Exeter, Stocker Road, Exeter, UK
- Department of Bioinformatics and Mathematical Modelling, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 105 Acad. G. Bonchev Str., 1113, Sofia, Bulgaria
| | - Stefano Pagliara
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK.
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9
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The Combination of In Vitro Assessment of Stress Tolerance Ability, Autoaggregation, and Vitamin B-Producing Ability for New Probiotic Strain Introduction. Microorganisms 2022; 10:microorganisms10020470. [PMID: 35208924 PMCID: PMC8879812 DOI: 10.3390/microorganisms10020470] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/13/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
The health benefits of probiotics are beyond doubt. The positive effects of lactobacilli and bifidobacteria on the function of many body systems have been repeatedly proven by various studies. To completely realize the potential of probiotic microorganisms, the strains should be tested by the greatest combination of characteristics that contribute to the wellness of the host. In this work, for the first time, a combined assessment of the probiotic properties and vitamin B-producing potential of various species and strains of bifidobacteria and lactobacilli was carried out. The presence of an additional advantage, such as vitamin-producing ability, can prevent vitamin deficiency both at the level of the consumption of fermented foods, when the enrichment will occur naturally on the spot, and during colonization by these intestinal strains, when synthesis will occur in vivo. To select potential probiotics, the stress tolerance ability of 16 lactic acid bacteria and bifidobacteria strains to low pH values, bile, and proteolytic enzymes, as well as their ability to autoaggregate, were studied under conditions of modeling the gastrointestinal tract in vitro. The ability of the strains to extracellularly accumulate water-soluble B vitamins was evaluated by capillary electrophoresis. Among the tested strains of bifidobacteria, B. adolescentis VKPM AC-1662 is of interest; it was characterized by the greatest stress tolerance ability and the ability to autoaggregate, in addition to the extracellular synthesis of riboflavin and pyridoxine. Among lactic acid bacteria, L. sakei VKPM B-8936 demonstrated the greatest tolerance to low pH, L. plantarum VKPM B–11007 to duodenal conditions, L. acidophilus VKPM B-2213 to pepsin, and L. salivarius VKPM B–2214 to pancreatin. The highest percentage of autoaggregation was observed in L. salivarius VKPM B-2214, which also accumulated the largest amount of pantothenic acid, but it was sensitive to stress conditions. The obtained results could be used to create new products enriched with probiotics and B vitamins.
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10
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Rodríguez-Rubio L, Haarmann N, Schwidder M, Muniesa M, Schmidt H. Bacteriophages of Shiga Toxin-Producing Escherichia coli and Their Contribution to Pathogenicity. Pathogens 2021; 10:404. [PMID: 33805526 PMCID: PMC8065619 DOI: 10.3390/pathogens10040404] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022] Open
Abstract
Shiga toxins (Stx) of Shiga toxin-producing Escherichia coli (STEC) are generally encoded in the genome of lambdoid bacteriophages, which spend the most time of their life cycle integrated as prophages in specific sites of the bacterial chromosome. Upon spontaneous induction or induction by chemical or physical stimuli, the stx genes are co-transcribed together with the late phase genes of the prophages. After being assembled in the cytoplasm, and after host cell lysis, mature bacteriophage particles are released into the environment, together with Stx. As members of the group of lambdoid phages, Stx phages share many genetic features with the archetypical temperate phage Lambda, but are heterogeneous in their DNA sequences due to frequent recombination events. In addition to Stx phages, the genome of pathogenic STEC bacteria may contain numerous prophages, which are either cryptic or functional. These prophages may carry foreign genes, some of them related to virulence, besides those necessary for the phage life cycle. Since the production of one or more Stx is considered the major pathogenicity factor of STEC, we aim to highlight the new insights on the contribution of Stx phages and other STEC phages to pathogenicity.
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Affiliation(s)
- Lorena Rodríguez-Rubio
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain; (L.R.-R.); (M.M.)
| | - Nadja Haarmann
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
| | - Maike Schwidder
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
| | - Maite Muniesa
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Diagonal 643, 08028 Barcelona, Spain; (L.R.-R.); (M.M.)
| | - Herbert Schmidt
- Department of Food Microbiology and Hygiene, Institute of Food Science and Biotechnology, University of Hohenheim, 70599 Stuttgart, Germany; (N.H.); (M.S.)
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Clarke L, Pelin A, Phan M, Wong A. The effect of environmental heterogeneity on the fitness of antibiotic resistance mutations in Escherichia coli. Evol Ecol 2020. [DOI: 10.1007/s10682-019-10027-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Haarmann N, Berger M, Kouzel IU, Mellmann A, Berger P. Comparative virulence characterization of the Shiga toxin phage-cured Escherichia coli O104:H4 and enteroaggregative Escherichia coli. Int J Med Microbiol 2018; 308:912-920. [DOI: 10.1016/j.ijmm.2018.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/04/2018] [Accepted: 06/16/2018] [Indexed: 12/26/2022] Open
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13
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Growth advantage of Escherichia coli O104:H4 strains on 5- N -acetyl-9- O -acetyl neuraminic acid as a carbon source is dependent on heterogeneous phage-Borne nanS-p esterases. Int J Med Microbiol 2018; 308:459-468. [DOI: 10.1016/j.ijmm.2018.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/15/2018] [Accepted: 03/19/2018] [Indexed: 01/10/2023] Open
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14
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Hoyer J, Bartel J, Gómez-Mejia A, Rohde M, Hirschfeld C, Heß N, Sura T, Maaß S, Hammerschmidt S, Becher D. Proteomic response of Streptococcus pneumoniae to iron limitation. Int J Med Microbiol 2018; 308:713-721. [PMID: 29496408 DOI: 10.1016/j.ijmm.2018.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 02/08/2018] [Accepted: 02/12/2018] [Indexed: 11/18/2022] Open
Abstract
Iron is an essential trace element and involved in various key metabolic pathways in bacterial lifestyle. Within the human host, iron is extremely limited. Hence, the ability of bacteria to acquire iron from the environment is critical for a successful infection. Streptococcus pneumoniae (the pneumococcus) is a human pathobiont colonizing symptomless the human respiratory tract, but can also cause various local and invasive infections. To survive and proliferate pneumococci have therefore to adapt their metabolism and virulence factor repertoire to different host compartments. In this study, the response of S. pneumoniae to iron limitation as infection-relevant condition was investigated on the proteome level. The iron limitation was induced by application of the iron chelator 2,2'-bipyridine (BIP) in two different media mimicking different physiological traits. Under these conditions, the influence of the initial iron concentration on pneumococcal protein expression in response to limited iron availability was analyzed. Interestingly, one major difference between these two iron limitation experiments is the regulation of proteins involved in pneumococcal pathogenesis. In iron-poor medium several proteins of this group were downregulated whereas these proteins are upregulated in iron-rich medium. However, iron limitation in both environments led to a strong upregulation of the iron uptake protein PiuA and the significant downregulation of the non-heme iron-containing ferritin Dpr. Based on the results, it is shown that the pneumococcal proteome response to iron limitation is strongly dependent on the initial iron concentration in the medium or the environment.
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Affiliation(s)
- Juliane Hoyer
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Jürgen Bartel
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Alejandro Gómez-Mejia
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Claudia Hirschfeld
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Nathalie Heß
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Thomas Sura
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Sandra Maaß
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Sven Hammerschmidt
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - Dörte Becher
- Department Microbial Proteomics, Institute for Microbiology, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany.
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Behr S, Kristoficova I, Witting M, Breland EJ, Eberly AR, Sachs C, Schmitt-Kopplin P, Hadjifrangiskou M, Jung K. Identification of a High-Affinity Pyruvate Receptor in Escherichia coli. Sci Rep 2017; 7:1388. [PMID: 28469239 PMCID: PMC5431176 DOI: 10.1038/s41598-017-01410-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 03/28/2017] [Indexed: 11/09/2022] Open
Abstract
Two-component systems are crucial for signal perception and modulation of bacterial behavior. Nevertheless, to date, very few ligands have been identified that directly interact with histidine kinases. The histidine kinase/response regulator system YehU/YehT of Escherichia coli is part of a nutrient-sensing network. Here we demonstrate that this system senses the onset of nutrient limitation in amino acid rich media and responds to extracellular pyruvate. Binding of radiolabeled pyruvate was found for full-length YehU in right-side-out membrane vesicles as well as for a truncated, membrane-integrated variant, confirming that YehU is a high-affinity receptor for extracellular pyruvate. Therefore we propose to rename YehU/YehT as BtsS/BtsR, after "Brenztraubensäure", the name given to pyruvic acid when it was first synthesized. The function of BtsS/BtsR was also assessed in a clinically relevant uropathogenic E. coli strain. Quantitative transcriptional analysis revealed BtsS/BtsR importance during acute and chronic urinary-tract infections.
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Affiliation(s)
- Stefan Behr
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, 82152, Martinsried, Germany
| | - Ivica Kristoficova
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, 82152, Martinsried, Germany
| | - Michael Witting
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Research Unit Analytical BioGeoChemistry, 85764, Neuherberg, Germany
| | - Erin J Breland
- Departments of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Allison R Eberly
- Departments of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Corinna Sachs
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, 82152, Martinsried, Germany
| | - Philippe Schmitt-Kopplin
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Research Unit Analytical BioGeoChemistry, 85764, Neuherberg, Germany
| | - Maria Hadjifrangiskou
- Departments of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Departments of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kirsten Jung
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, 82152, Martinsried, Germany.
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Escherichia coli O157:H7 Strain EDL933 Harbors Multiple Functional Prophage-Associated Genes Necessary for the Utilization of 5-N-Acetyl-9-O-Acetyl Neuraminic Acid as a Growth Substrate. Appl Environ Microbiol 2016; 82:5940-50. [PMID: 27474715 DOI: 10.1128/aem.01671-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/14/2016] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 harbors multiple prophage-associated open reading frames (ORFs) in its genome which are highly homologous to the chromosomal nanS gene. The latter is part of the nanCMS operon, which is present in most E. coli strains and encodes an esterase which is responsible for the monodeacetylation of 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Whereas one prophage-borne ORF (z1466) has been characterized in previous studies, the functions of the other nanS-homologous ORFs are unknown. In the current study, the nanS-homologous ORFs of EDL933 were initially studied in silico Due to their homology to the chromosomal nanS gene and their location in prophage genomes, we designated them nanS-p and numbered the different nanS-p alleles consecutively from 1 to 10. The two alleles nanS-p2 and nanS-p4 were selected for production of recombinant proteins, their enzymatic activities were investigated, and differences in their temperature optima were found. Furthermore, a function of these enzymes in substrate utilization could be demonstrated using an E. coli C600ΔnanS mutant in a growth medium with Neu5,9Ac2 as the carbon source and supplementation with the different recombinant NanS-p proteins. Moreover, generation of sequential deletions of all nanS-p alleles in strain EDL933 and subsequent growth experiments demonstrated a gene dose effect on the utilization of Neu5,9Ac2 Since Neu5,9Ac2 is an important component of human and animal gut mucus and since the nutrient availability in the large intestine is limited, we hypothesize that the presence of multiple Neu5,9Ac2 esterases provides them a nutrient supply under certain conditions in the large intestine, even if particular prophages are lost. IMPORTANCE In this study, a group of homologous prophage-borne nanS-p alleles and two of the corresponding enzymes of enterohemorrhagic E. coli (EHEC) O157:H7 strain EDL933 that may be important to provide alternative genes for substrate utilization were characterized.
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Wallace N, Zani A, Abrams E, Sun Y. The Impact of Oxygen on Bacterial Enteric Pathogens. ADVANCES IN APPLIED MICROBIOLOGY 2016; 95:179-204. [PMID: 27261784 DOI: 10.1016/bs.aambs.2016.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacterial enteric pathogens are responsible for a tremendous amount of foodborne illnesses every year through the consumption of contaminated food products. During their transit from contaminated food sources to the host gastrointestinal tract, these pathogens are exposed and must adapt to fluctuating oxygen levels to successfully colonize the host and cause diseases. However, the majority of enteric infection research has been conducted under aerobic conditions. To raise awareness of the importance in understanding the impact of oxygen, or lack of oxygen, on enteric pathogenesis, we describe in this review the metabolic and physiological responses of nine bacterial enteric pathogens exposed to environments with different oxygen levels. We further discuss the effects of oxygen levels on virulence regulation to establish potential connections between metabolic adaptations and bacterial pathogenesis. While not providing an exhaustive list of all bacterial pathogens, we highlight key differences and similarities among nine facultative anaerobic and microaerobic pathogens in this review to argue for a more in-depth understanding of the diverse impact oxygen levels have on enteric pathogenesis.
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Affiliation(s)
- N Wallace
- University of Dayton, Dayton, OH, United States
| | - A Zani
- University of Dayton, Dayton, OH, United States
| | - E Abrams
- University of Dayton, Dayton, OH, United States
| | - Y Sun
- University of Dayton, Dayton, OH, United States
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Abstract
Sialic acids, or the more broad term nonulosonic acids, comprise a family of nine-carbon keto-sugars ubiquitous on mammalian mucous membranes as terminal modifications of mucin glycoproteins. Sialic acids have a limited distribution among bacteria, and the ability to catabolize sialic acids is mainly confined to pathogenic and commensal species. This ability to utilize sialic acid as a carbon source is correlated with bacterial virulence, especially, in the sialic acid rich environment of the oral cavity, respiratory, intestinal, and urogenital tracts. This chapter discusses the distribution of sialic acid catabolizers among the sequenced bacterial genomes and examines the studies that have linked sialic acid catabolism with increased in vivo fitness in a number of species using several animal models. This chapter presents the most recent findings in sialobiology with a focus on sialic acid catabolism, which demonstrates an important relationship between the catabolism of sialic acid and bacterial pathogenesis.
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Characterization of urinary tract infection-associated Shiga toxin-producing Escherichia coli. Infect Immun 2014; 82:4631-42. [PMID: 25156739 DOI: 10.1128/iai.01701-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC), a subgroup of Shiga toxin (Stx)-producing E. coli (STEC), is a leading cause of diarrhea and hemolytic-uremic syndrome (HUS) in humans. However, urinary tract infections (UTIs) caused by this microorganism but not associated with diarrhea have occasionally been reported. We geno- and phenotypically characterized three EHEC isolates obtained from the urine of hospitalized patients suffering from UTIs. These isolates carried typical EHEC virulence markers and belonged to HUS-associated E. coli (HUSEC) clones, but they lacked virulence markers typical of uropathogenic E. coli. One isolate exhibited a localized adherence (LA)-like pattern on T24 urinary bladder epithelial cells. Since the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) are well-known receptors for Stx but also for P fimbriae, a major virulence factor of extraintestinal pathogenic E. coli (ExPEC), the expression of Gb3Cer and Gb4Cer by T24 cells and in murine urinary bladder tissue was examined by thin-layer chromatography and mass spectrometry. We provide data indicating that Stxs released by the EHEC isolates bind to Gb3Cer and Gb4Cer isolated from T24 cells, which were susceptible to Stx. All three EHEC isolates expressed stx genes upon growth in urine. Two strains were able to cause UTI in a murine infection model and could not be outcompeted in urine in vitro by typical uropathogenic E. coli isolates. Our results indicate that despite the lack of ExPEC virulence markers, EHEC variants may exhibit in certain suitable hosts, e.g., in hospital patients, a uropathogenic potential. The contribution of EHEC virulence factors to uropathogenesis remains to be further investigated.
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Bacteriophage 933W encodes a functional esterase downstream of the Shiga toxin 2a operon. Int J Med Microbiol 2014; 304:269-74. [DOI: 10.1016/j.ijmm.2013.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/26/2013] [Accepted: 10/20/2013] [Indexed: 11/19/2022] Open
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Tran SL, Billoud L, Lewis SB, Phillips AD, Schüller S. Shiga toxin production and translocation during microaerobic human colonic infection with Shiga toxin-producing E. coli O157:H7 and O104:H4. Cell Microbiol 2014; 16:1255-66. [PMID: 24612002 PMCID: PMC4231982 DOI: 10.1111/cmi.12281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/31/2014] [Accepted: 02/14/2014] [Indexed: 12/30/2022]
Abstract
Haemolytic uraemic syndrome caused by Shiga toxin-producing E. coli (STEC) is dependent on release of Shiga toxins (Stxs) during intestinal infection and subsequent absorption into the bloodstream. An understanding of Stx-related events in the human gut is limited due to lack of suitable experimental models. In this study, we have used a vertical diffusion chamber system with polarized human colon carcinoma cells to simulate the microaerobic (MA) environment in the human intestine and investigate its influence on Stx release and translocation during STEC O157:H7 and O104:H4 infection. Stx2 was the major toxin type released during infection. Whereas microaerobiosis significantly reduced bacterial growth as well as Stx production and release into the medium, Stx translocation across the epithelial monolayer was enhanced under MA versus aerobic conditions. Increased Stx transport was dependent on STEC infection and occurred via a transcellular pathway other than macropinocytosis. While MA conditions had a similar general effect on Stx release and absorption during infection with STEC O157:H7 and O104:H4, both serotypes showed considerable differences in colonization, Stx production, and Stx translocation which suggest alternative virulence strategies. Taken together, our study suggests that the MA environment in the human colon may modulate Stx-related events and enhance Stx absorption during STEC infection.
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Affiliation(s)
- Seav-Ly Tran
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK; Gut Health and Food Safety Programme, Institute of Food Research, Norwich Research Park, Norwich, UK
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