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Kumwenda B, Canals R, Predeus AV, Zhu X, Kröger C, Pulford C, Wenner N, Lora LL, Li Y, Owen SV, Everett D, Hokamp K, Heyderman RS, Ashton PM, Gordon MA, Msefula CL, Hinton JCD. Salmonella enterica serovar Typhimurium ST313 sublineage 2.2 has emerged in Malawi with a characteristic gene expression signature and a fitness advantage. MICROLIFE 2024; 5:uqae005. [PMID: 38623411 PMCID: PMC11018118 DOI: 10.1093/femsml/uqae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
Invasive non-typhoidal Salmonella (iNTS) disease is a serious bloodstream infection that targets immune-compromised individuals, and causes significant mortality in sub-Saharan Africa. Salmonella enterica serovar Typhimurium ST313 causes the majority of iNTS in Malawi. We performed an intensive comparative genomic analysis of 608 S. Typhimurium ST313 isolates dating between 1996 and 2018 from Blantyre, Malawi. We discovered that following the arrival of the well-characterized S. Typhimurium ST313 lineage 2 in 1999, two multidrug-resistant variants emerged in Malawi in 2006 and 2008, designated sublineages 2.2 and 2.3, respectively. The majority of S. Typhimurium isolates from human bloodstream infections in Malawi now belong to sublineages 2.2 or 2.3. To understand the emergence of the prevalent ST313 sublineage 2.2, we studied two representative strains, D23580 (lineage 2) and D37712 (sublineage 2.2). The chromosome of ST313 lineage 2 and sublineage 2.2 only differed by 29 SNPs/small indels and a 3 kb deletion of a Gifsy-2 prophage region including the sseI pseudogene. Lineage 2 and sublineage 2.2 had distinctive plasmid profiles. The transcriptome was investigated in 15 infection-relevant in vitro conditions and within macrophages. During growth in physiological conditions that do not usually trigger S. Typhimurium SPI2 gene expression, the SPI2 genes of D37712 were transcriptionally active. We identified down-regulation of flagellar genes in D37712 compared with D23580. Following phenotypic confirmation of transcriptomic differences, we discovered that sublineage 2.2 had increased fitness compared with lineage 2 during mixed growth in minimal media. We speculate that this competitive advantage is contributing to the emergence of sublineage 2.2 in Malawi.
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Affiliation(s)
- Benjamin Kumwenda
- School of Life Sciences and Allied Health Professions, Kamuzu University of Health Sciences Blantyre, Blantyre, 265, Malawi
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Rocío Canals
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Alexander V Predeus
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Xiaojun Zhu
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Carsten Kröger
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Caisey Pulford
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Nicolas Wenner
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Lizeth Lacharme Lora
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Yan Li
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Siân V Owen
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Dean Everett
- Department of Public Health and Epidemiology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, P.O. Box 127788, United Arab Emirates
| | - Karsten Hokamp
- Smurfit Institute of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, D02 PN40, Ireland
| | - Robert S Heyderman
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
- Research Department of Infection, Division of Infection & Immunity, University College London, London, WC1E 6BT, United Kingdom
| | | | - Melita A Gordon
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Chisomo L Msefula
- School of Life Sciences and Allied Health Professions, Kamuzu University of Health Sciences Blantyre, Blantyre, 265, Malawi
- Malawi–Liverpool–Wellcome Programme, Blantyre, 3, Malawi
| | - Jay C D Hinton
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
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Conley HE, Brown CF, Westerman TL, Elfenbein JR, Sheats MK. MARCKS Inhibition Alters Bovine Neutrophil Responses to Salmonella Typhimurium. Biomedicines 2024; 12:442. [PMID: 38398044 PMCID: PMC10886653 DOI: 10.3390/biomedicines12020442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/08/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Neutrophils are innate immune cells that respond quickly to sites of bacterial infection and play an essential role in host defense. Interestingly, some bacterial pathogens benefit from exuberant neutrophil inflammation. Salmonella is one such pathogen that can utilize the toxic mediators released by neutrophils to colonize the intestine and cause enterocolitis. Because neutrophils can aid gut colonization during Salmonella infection, neutrophils represent a potential host-directed therapeutic target. Myristoylated alanine-rich C-kinase substrate (MARCKS) is an actin-binding protein that plays an essential role in many neutrophil effector responses. We hypothesized that inhibition of MARCKS protein would alter bovine neutrophil responses to Salmonella Typhimurium (STm) ex vivo. We used a MARCKS inhibitor peptide to investigate the role of MARCKS in neutrophil responses to STm. This study demonstrates that MARCKS inhibition attenuated STm-induced neutrophil adhesion and chemotaxis. Interestingly, MARCKS inhibition also enhanced neutrophil phagocytosis and respiratory burst in response to STm. This is the first report describing the role of MARCKS protein in neutrophil antibacterial responses.
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Affiliation(s)
- Haleigh E Conley
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
| | - Chalise F Brown
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Trina L Westerman
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Johanna R Elfenbein
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - M Katie Sheats
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA
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Lentsch V, Aslani S, Echtermann T, Preet S, Cappio Barazzone E, Hoces D, Moresi C, Kümmerlen D, Slack E. "EvoVax" - A rationally designed inactivated Salmonella Typhimurium vaccine induces strong and long-lasting immune responses in pigs. Vaccine 2023; 41:5545-5552. [PMID: 37517910 DOI: 10.1016/j.vaccine.2023.07.059] [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: 03/31/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Salmonella enterica subspecies enterica serovar Typhimurium (S.Tm) poses a considerable threat to public health due to its zoonotic potential. Human infections are mostly foodborne, and pork and pork products are ranked among the top culprits for transmission. In addition, the high percentage of antibiotic resistance, especially in monophasic S.Tm, limits treatment options when needed. Better S.Tm control would therefore be of benefit both for farm animals and for safety of the human food chain. A promising pre-harvest intervention is vaccination. In this study we tested safety and immunogenicity of an oral inactivated S.Tm vaccine, which has been recently shown to generate an "evolutionary trap" and to massively reduce S.Tm colonization and transmission in mice. We show that this vaccine is highly immunogenic and safe in post-weaning pigs and that administration of a single oral dose results in a strong and long-lasting serum IgG response. This has several advantages over existing - mainly live - vaccines against S.Tm, both in improved seroconversion and reduced risk of vaccine-strain persistence and reversion to virulence.
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Affiliation(s)
- Verena Lentsch
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Selma Aslani
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Thomas Echtermann
- Division of Swine Medicine, Department for Farm Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Swapan Preet
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | | | - Daniel Hoces
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Claudia Moresi
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Dolf Kümmerlen
- Division of Swine Medicine, Department for Farm Animals, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Emma Slack
- Institute for Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland; Botnar Research Centre for Child Health, Basel, Switzerland.
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Chatterjee R, Chowdhury AR, Mukherjee D, Chakravortty D. From Eberthella typhi to Salmonella Typhi: The Fascinating Journey of the Virulence and Pathogenicity of Salmonella Typhi. ACS OMEGA 2023; 8:25674-25697. [PMID: 37521659 PMCID: PMC10373206 DOI: 10.1021/acsomega.3c02386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 06/30/2023] [Indexed: 08/01/2023]
Abstract
Salmonella Typhi (S. Typhi), the invasive typhoidal serovar of Salmonella enterica that causes typhoid fever in humans, is a severe threat to global health. It is one of the major causes of high morbidity and mortality in developing countries. According to recent WHO estimates, approximately 11-21 million typhoid fever illnesses occur annually worldwide, accounting for 0.12-0.16 million deaths. Salmonella infection can spread to healthy individuals by the consumption of contaminated food and water. Typhoid fever in humans sometimes is accompanied by several other critical extraintestinal complications related to the central nervous system, cardiovascular system, pulmonary system, and hepatobiliary system. Salmonella Pathogenicity Island-1 and Salmonella Pathogenicity Island-2 are the two genomic segments containing genes encoding virulent factors that regulate its invasion and systemic pathogenesis. This Review aims to shed light on a comparative analysis of the virulence and pathogenesis of the typhoidal and nontyphoidal serovars of S. enterica.
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Affiliation(s)
- Ritika Chatterjee
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Atish Roy Chowdhury
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Debapriya Mukherjee
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Dipshikha Chakravortty
- Department
of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Centre
for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Nagarajan A, Scoggin K, Gupta J, Threadgill DW, Andrews-Polymenis HL. Using the collaborative cross to identify the role of host genetics in defining the murine gut microbiome. MICROBIOME 2023; 11:149. [PMID: 37420306 PMCID: PMC10329326 DOI: 10.1186/s40168-023-01552-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 04/18/2023] [Indexed: 07/09/2023]
Abstract
BACKGROUND The human gut microbiota is a complex community comprised of trillions of bacteria and is critical for the digestion and absorption of nutrients. Bacterial communities of the intestinal microbiota influence the development of several conditions and diseases. We studied the effect of host genetics on gut microbial composition using Collaborative Cross (CC) mice. CC mice are a panel of mice that are genetically diverse across strains, but genetically identical within a given strain allowing repetition and deeper analysis than is possible with other collections of genetically diverse mice. RESULTS 16S rRNA from the feces of 167 mice from 28 different CC strains was sequenced and analyzed using the Qiime2 pipeline. We observed a large variance in the bacterial composition across CC strains starting at the phylum level. Using bacterial composition data, we identified 17 significant Quantitative Trait Loci (QTL) linked to 14 genera on 9 different mouse chromosomes. Genes within these intervals were analyzed for significant association with pathways and the previously known human GWAS database using Enrichr analysis and Genecards database. Multiple host genes involved in obesity, glucose homeostasis, immunity, neurological diseases, and many other protein-coding genes located in these regions may play roles in determining the composition of the gut microbiota. A subset of these CC mice was infected with Salmonella Typhimurium. Using infection outcome data, an increase in abundance of genus Lachnospiraceae and decrease in genus Parasutterella correlated with positive health outcomes after infection. Machine learning classifiers accurately predicted the CC strain and the infection outcome using pre-infection bacterial composition data from the feces. CONCLUSION Our study supports the hypothesis that multiple host genes influence the gut microbiome composition and homeostasis, and that certain organisms may influence health outcomes after S. Typhimurium infection. Video Abstract.
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Affiliation(s)
- Aravindh Nagarajan
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, TX USA
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX USA
| | - Kristin Scoggin
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, TX USA
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX USA
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX USA
| | - Jyotsana Gupta
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX USA
| | - David W. Threadgill
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, TX USA
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX USA
- Texas A&M Institute for Genome Sciences and Society, Texas A&M University, College Station, TX USA
- Department of Biochemistry & Biophysics and Department of Nutrition, Texas A&M University, College Station, TX USA
| | - Helene L. Andrews-Polymenis
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, TX USA
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX USA
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Bogomolnaya L, Talamantes M, Rocha J, Nagarajan A, Zhu W, Spiga L, Winter MG, Konganti K, Adams LG, Winter S, Andrews-Polymenis H. Taxonomic and Metagenomic Analyses Define the Development of the Microbiota in the Chick. mBio 2023; 14:e0244422. [PMID: 36475774 PMCID: PMC9973254 DOI: 10.1128/mbio.02444-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/08/2022] [Indexed: 12/13/2022] Open
Abstract
Chicks are ideal to follow the development of the intestinal microbiota and to understand how a pathogen perturbs this developing population. Taxonomic/metagenomic analyses captured the development of the chick microbiota in unperturbed chicks and in chicks infected with Salmonella enterica serotype Typhimurium (STm) during development. Taxonomic analysis suggests that colonization by the chicken microbiota takes place in several waves. The cecal microbiota stabilizes at day 12 posthatch with prominent Gammaproteobacteria and Clostridiales. Introduction of S. Typhimurium at day 4 posthatch disrupted the expected waves of intestinal colonization. Taxonomic and metagenomic shotgun sequencing analyses allowed us to identify species present in uninfected chicks. Untargeted metabolomics suggested different metabolic activities in infected chick microbiota. This analysis and gas chromatography-mass spectrometry on ingesta confirmed that lactic acid in cecal content coincides with the stable presence of enterococci in STm-infected chicks. Unique metabolites, including 2-isopropylmalic acid, an intermediate in the biosynthesis of leucine, were present only in the cecal content of STm-infected chicks. The metagenomic data suggested that the microbiota in STm-infected chicks contained a higher abundance of genes, from STm itself, involved in branched-chain amino acid synthesis. We generated an ilvC deletion mutant (STM3909) encoding ketol-acid-reductoisomerase, a gene required for the production of l-isoleucine and l-valine. ΔilvC mutants are disadvantaged for growth during competitive infection with the wild type. Providing the ilvC gene in trans restored the growth of the ΔilvC mutant. Our integrative approach identified biochemical pathways used by STm to establish a colonization niche in the chick intestine during development. IMPORTANCE Chicks are an ideal model to follow the development of the intestinal microbiota and to understand how a pathogen perturbs this developing population. Using taxonomic and metagenomic analyses, we captured the development of chick microbiota to 19 days posthatch in unperturbed chicks and in chicks infected with Salmonella enterica serotype Typhimurium (STm). We show that normal development of the microbiota takes place in waves and is altered in the presence of a pathogen. Metagenomics and metabolomics suggested that branched-chain amino acid biosynthesis is especially important for Salmonella growth in the infected chick intestine. Salmonella mutants unable to make l-isoleucine and l-valine colonize the chick intestine poorly. Restoration of the pathway for biosynthesis of these amino acids restored the colonizing ability of Salmonella. Integration of multiple analyses allowed us to correctly identify biochemical pathways used by Salmonella to establish a niche for colonization in the chick intestine during development.
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Affiliation(s)
- Lydia Bogomolnaya
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
- Deparment of Biomedical Sciences, Marshall University, Huntington, West Virginia, USA
| | - Marissa Talamantes
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
| | - Joana Rocha
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
| | - Aravindh Nagarajan
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, USA
| | - Wenhan Zhu
- Department of Microbiology and Immunology, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Luisella Spiga
- Department of Microbiology and Immunology, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Maria G. Winter
- Department of Microbiology and Immunology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Kranti Konganti
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M, College Station, Texas, USA
| | - L. Garry Adams
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M, College Station, Texas, USA
| | - Sebastian Winter
- Department of Microbiology and Immunology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Helene Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, Texas, USA
- Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas, USA
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Cruz E, Haeberle AL, Westerman TL, Durham ME, Suyemoto MM, Knodler LA, Elfenbein JR. Nonredundant Dimethyl Sulfoxide Reductases Influence Salmonella enterica Serotype Typhimurium Anaerobic Growth and Virulence. Infect Immun 2023; 91:e0057822. [PMID: 36722978 PMCID: PMC9933680 DOI: 10.1128/iai.00578-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/02/2023] Open
Abstract
Facultative anaerobic enteric pathogens can utilize a diverse array of alternate electron acceptors to support anaerobic metabolism and thrive in the hypoxic conditions within the mammalian gut. Dimethyl sulfoxide (DMSO) is produced by methionine catabolism and can act as an alternate electron acceptor to support anaerobic respiration. The DMSO reductase complex consists of three subunits, DmsA, DmsB, and DmsC, and allows bacteria to grow anaerobically with DMSO as an electron acceptor. The genomes of nontyphoidal Salmonella enterica encode three putative dmsABC operons, but the impact of the apparent genetic redundancy in DMSO reduction on the fitness of nontyphoidal S. enterica during infection remains unknown. We hypothesized that DMSO reduction would be needed for S. enterica serotype Typhimurium to colonize the mammalian gut. We demonstrate that an S. Typhimurium mutant with loss of function in all three putative DMSO reductases (ΔdmsA3) poorly colonizes the mammalian intestine when the microbiota is intact and when inflammation is absent. DMSO reduction enhances anaerobic growth through nonredundant contributions of two of the DMSO reductases. Furthermore, DMSO reduction influences virulence by increasing expression of the type 3 secretion system 2 and reducing expression of the type 3 secretion system 1. Collectively, our data demonstrate that the DMSO reductases of S. Typhimurium are functionally nonredundant and suggest DMSO is a physiologically relevant electron acceptor that supports S. enterica fitness in the gut.
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Affiliation(s)
- E. Cruz
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - A. L. Haeberle
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - T. L. Westerman
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - M. E. Durham
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - M. M. Suyemoto
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - L. A. Knodler
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - J. R. Elfenbein
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
- Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
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8
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Wang Q, Kim H, Halvorsen TM, Chen S, Hayes CS, Buie CR. Leveraging microfluidic dielectrophoresis to distinguish compositional variations of lipopolysaccharide in E. coli. Front Bioeng Biotechnol 2023; 11:991784. [PMID: 36873367 PMCID: PMC9979706 DOI: 10.3389/fbioe.2023.991784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 02/03/2023] [Indexed: 02/18/2023] Open
Abstract
Lipopolysaccharide (LPS) is the unique feature that composes the outer leaflet of the Gram-negative bacterial cell envelope. Variations in LPS structures affect a number of physiological processes, including outer membrane permeability, antimicrobial resistance, recognition by the host immune system, biofilm formation, and interbacterial competition. Rapid characterization of LPS properties is crucial for studying the relationship between these LPS structural changes and bacterial physiology. However, current assessments of LPS structures require LPS extraction and purification followed by cumbersome proteomic analysis. This paper demonstrates one of the first high-throughput and non-invasive strategies to directly distinguish Escherichia coli with different LPS structures. Using a combination of three-dimensional insulator-based dielectrophoresis (3DiDEP) and cell tracking in a linear electrokinetics assay, we elucidate the effect of structural changes in E. coli LPS oligosaccharides on electrokinetic mobility and polarizability. We show that our platform is sufficiently sensitive to detect LPS structural variations at the molecular level. To correlate electrokinetic properties of LPS with the outer membrane permeability, we further examined effects of LPS structural variations on bacterial susceptibility to colistin, an antibiotic known to disrupt the outer membrane by targeting LPS. Our results suggest that microfluidic electrokinetic platforms employing 3DiDEP can be a useful tool for isolating and selecting bacteria based on their LPS glycoforms. Future iterations of these platforms could be leveraged for rapid profiling of pathogens based on their surface LPS structural identity.
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Affiliation(s)
- Qianru Wang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Hyungseok Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Tiffany M Halvorsen
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Sijie Chen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Cullen R Buie
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
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9
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Fernández-Fernández R, Olivenza DR, Sánchez-Romero MA. Identifying Bacterial Lineages in Salmonella by Flow Cytometry. EcoSal Plus 2022; 10:eESP00182021. [PMID: 35148202 PMCID: PMC10729938 DOI: 10.1128/ecosalplus.esp-0018-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 12/21/2021] [Indexed: 12/16/2022]
Abstract
Advances in technologies that permit high-resolution analysis of events in single cells have revealed that phenotypic heterogeneity is a widespread phenomenon in bacteria. Flow cytometry has the potential to describe the distribution of cellular properties within a population of bacterial cells and has yielded invaluable information about the ability of isogenic cells to diversify into phenotypic subpopulations. This review will discuss several single-cell approaches that have recently been applied to define phenotypic heterogeneity in populations of Salmonella enterica.
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Affiliation(s)
| | - David R. Olivenza
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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Shikov AE, Belousova ME, Belousov MV, Nizhnikov AA, Antonets KS. Salmonella-Based Biorodenticides: Past Applications and Current Contradictions. Int J Mol Sci 2022; 23:ijms232314595. [PMID: 36498920 PMCID: PMC9736839 DOI: 10.3390/ijms232314595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/03/2022] [Accepted: 11/14/2022] [Indexed: 11/24/2022] Open
Abstract
The idea of using pathogens to control pests has existed since the end of the 19th century. Enterobacteria from the genus Salmonella, discovered at that time, are the causative agents of many serious diseases in mammals often leading to death. Mostly, the strains of Salmonella are able to infect a wide spectrum of hosts belonging to vertebrates, but some of them show host restriction. Several strains of these bacteria have been used as biorodenticides due to the host restriction until they were banned in many countries in the second part of the 20th century. The main reason for the ban was their potential pathogenicity for some domestic animals and poultry and the outbreaks of gastroenteritis in humans. Since that time, a lot of data regarding the host specificity and host restriction of different strains of Salmonella have been accumulated, and the complexity of the molecular mechanisms affecting it has been uncovered. In this review, we summarize the data regarding the history of studying and application of Salmonella-based rodenticides, discuss molecular systems controlling the specificity of Salmonella interactions within its multicellular hosts at different stages of infection, and attempt to reconstruct the network of genes and their allelic variants which might affect the host-restriction mechanisms.
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Affiliation(s)
- Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
| | - Mikhail V. Belousov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), Pushkin, St. Petersburg 196608, Russia
- Faculty of Biology, St. Petersburg State University, St. Petersburg 199034, Russia
- Correspondence:
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11
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Elucidating Mechanisms of Tolerance to Salmonella Typhimurium across Long-Term Infections Using the Collaborative Cross. mBio 2022; 13:e0112022. [PMID: 35880881 PMCID: PMC9426527 DOI: 10.1128/mbio.01120-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Understanding the molecular mechanisms underlying resistance and tolerance to pathogen infection may present the opportunity to develop novel interventions. Resistance is the absence of clinical disease with a low pathogen burden, while tolerance is minimal clinical disease with a high pathogen burden. Salmonella is a worldwide health concern. We studied 18 strains of collaborative cross mice that survive acute Salmonella Typhimurium (STm) infections. We infected these strains orally and monitored them for 3 weeks. Five strains cleared STm (resistant), six strains maintained a bacterial load and survived (tolerant), while seven strains survived >7 days but succumbed to infection within the study period and were called “delayed susceptible.” Tolerant strains were colonized in the Peyer’s patches, mesenteric lymph node, spleen, and liver, while resistant strains had significantly reduced bacterial colonization. Tolerant strains had lower preinfection core body temperatures and had disrupted circadian patterns of body temperature postinfection sooner than other strains. Tolerant strains had higher circulating total white blood cells than resistant strains, driven by increased numbers of neutrophils. Tolerant strains had more severe tissue damage and higher circulating levels of monocyte chemoattractant protein 1 (MCP-1) and interferon gamma (IFN-γ), but lower levels of epithelial neutrophil-activating protein 78 (ENA-78) than resistant strains. Quantitative trait locus (QTL) analysis revealed one significant association and six suggestive associations. Gene expression analysis identified 22 genes that are differentially regulated in tolerant versus resistant animals that overlapped these QTLs. Fibrinogen genes (Fga, Fgb, and Fgg) were found across the QTL, RNA, and top canonical pathways, making them the best candidate genes for differentiating tolerance and resistance.
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12
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Genetic background influences survival of infections with Salmonella enterica serovar Typhimurium in the Collaborative Cross. PLoS Genet 2022; 18:e1010075. [PMID: 35417454 PMCID: PMC9067680 DOI: 10.1371/journal.pgen.1010075] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/04/2022] [Accepted: 03/25/2022] [Indexed: 12/18/2022] Open
Abstract
Salmonella infections typically cause self-limiting gastroenteritis, but in some individuals these bacteria can spread systemically and cause disseminated disease. Salmonella Typhimurium (STm), which causes severe systemic disease in most inbred mice, has been used as a model for disseminated disease. To screen for new infection phenotypes across a range of host genetics, we orally infected 32 Collaborative Cross (CC) mouse strains with STm and monitored their disease progression for seven days by telemetry. Our data revealed a broad range of phenotypes across CC strains in many parameters including survival, bacterial colonization, tissue damage, complete blood counts (CBC), and serum cytokines. Eighteen CC strains survived to day 7, while fourteen susceptible strains succumbed to infection before day 7. Several CC strains had sex differences in survival and colonization. Surviving strains had lower pre-infection baseline temperatures and were less active during their daily active period. Core body temperature disruptions were detected earlier after STm infection than activity disruptions, making temperature a better detector of illness. All CC strains had STm in spleen and liver, but susceptible strains were more highly colonized. Tissue damage was weakly negatively correlated to survival. We identified loci associated with survival on Chromosomes (Chr) 1, 2, 4, 7. Polymorphisms in Ncf2 and Slc11a1, known to reduce survival in mice after STm infections, are located in the Chr 1 interval, and the Chr 7 association overlaps with a previously identified QTL peak called Ses2. We identified two new genetic regions on Chr 2 and 4 associated with susceptibility to STm infection. Our data reveal the diversity of responses to STm infection across a range of host genetics and identified new candidate regions for survival of STm infection.
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13
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Abstract
Regulation of flagellum biosynthesis is a hierarchical process that is tightly controlled to allow for efficient tuning of flagellar expression. Flagellum-mediated motility directs Salmonella enterica serovar Typhimurium toward the epithelial surface to enhance gut colonization, but flagella are potent activators of innate immune signaling, so fine-tuning flagellar expression is necessary for immune avoidance. In this work, we evaluate the role of the LysR transcriptional regulator YeiE in regulating flagellum-mediated motility. We show that yeiE is necessary and sufficient for swimming motility. A ΔyeiE mutant is defective for gut colonization in both the calf ligated ileal loop model and the murine colitis model due to its lack of motility. Expression of flagellar class 2 and 3 but not class 1 genes is reduced in the ΔyeiE mutant. We linked the motility dysregulation of the ΔyeiE mutant to repression of the anti-FlhD4C2 factor STM1697. Together, our results indicate that YeiE promotes virulence by enhancing cell motility, thereby providing a new regulatory control point for flagellar expression in Salmonella Typhimurium.
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14
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Diard M, Bakkeren E, Lentsch V, Rocker A, Bekele NA, Hoces D, Aslani S, Arnoldini M, Böhi F, Schumann-Moor K, Adamcik J, Piccoli L, Lanzavecchia A, Stadtmueller BM, Donohue N, van der Woude MW, Hockenberry A, Viollier PH, Falquet L, Wüthrich D, Bonfiglio F, Loverdo C, Egli A, Zandomeneghi G, Mezzenga R, Holst O, Meier BH, Hardt WD, Slack E. A rationally designed oral vaccine induces immunoglobulin A in the murine gut that directs the evolution of attenuated Salmonella variants. Nat Microbiol 2021; 6:830-841. [PMID: 34045711 PMCID: PMC7611113 DOI: 10.1038/s41564-021-00911-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 04/14/2021] [Indexed: 12/12/2022]
Abstract
The ability of gut bacterial pathogens to escape immunity by antigenic variation-particularly via changes to surface-exposed antigens-is a major barrier to immune clearance1. However, not all variants are equally fit in all environments2,3. It should therefore be possible to exploit such immune escape mechanisms to direct an evolutionary trade-off. Here, we demonstrate this phenomenon using Salmonella enterica subspecies enterica serovar Typhimurium (S.Tm). A dominant surface antigen of S.Tm is its O-antigen: a long, repetitive glycan that can be rapidly varied by mutations in biosynthetic pathways or by phase variation4,5. We quantified the selective advantage of O-antigen variants in the presence and absence of O-antigen-specific immunoglobulin A and identified a set of evolutionary trajectories allowing immune escape without an associated fitness cost in naive mice. Through the use of rationally designed oral vaccines, we induced immunoglobulin A responses blocking all of these trajectories. This selected for Salmonella mutants carrying deletions of the O-antigen polymerase gene wzyB. Due to their short O-antigen, these evolved mutants were more susceptible to environmental stressors (detergents or complement) and predation (bacteriophages) and were impaired in gut colonization and virulence in mice. Therefore, a rationally induced cocktail of intestinal antibodies can direct an evolutionary trade-off in S.Tm. This lays the foundations for the exploration of mucosal vaccines capable of setting evolutionary traps as a prophylactic strategy.
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Affiliation(s)
- Médéric Diard
- Biozentrum, University of Basel, Basel, Switzerland.
| | - Erik Bakkeren
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland.,Department of Zoology, University of Oxford, Oxford, UK
| | - Verena Lentsch
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland
| | | | | | - Daniel Hoces
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland
| | - Selma Aslani
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland
| | - Markus Arnoldini
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland
| | - Flurina Böhi
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland.,Department of Molecular Mechanisms of Disease, University of Zürich, Zürich, Switzerland
| | - Kathrin Schumann-Moor
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland.,Division of Surgical Research, University Hospital of Zürich, Zürich, Switzerland
| | - Jozef Adamcik
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland
| | - Luca Piccoli
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Antonio Lanzavecchia
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Beth M Stadtmueller
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicholas Donohue
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK.,Department of Orthopedics and Trauma, Medical University of Graz, Graz, Austria
| | - Marjan W van der Woude
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Alyson Hockenberry
- Department of Environmental Microbiology, Eawag, Dubendorf, Switzerland.,Department of Environmental Sciences, ETH Zürich, Zürich, Switzerland
| | - Patrick H Viollier
- Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Laurent Falquet
- Department of Biology, University of Fribourg, Fribourg, Switzerland.,Swiss Institute of Bioinformatics, Fribourg, Switzerland
| | - Daniel Wüthrich
- Infection Biology, University Hospital of Basel, Basel, Switzerland
| | | | - Claude Loverdo
- Department of Materials, ETH Zürich, Zürich, Switzerland
| | - Adrian Egli
- Infection Biology, University Hospital of Basel, Basel, Switzerland.,Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Raffaele Mezzenga
- Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland.,Department of Materials, ETH Zürich, Zürich, Switzerland
| | - Otto Holst
- Forschungszentrum Borstel, Borstel, Germany
| | - Beat H Meier
- Institute for Physical Chemistry, ETH Zürich, Zürich, Switzerland
| | - Wolf-Dietrich Hardt
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland.
| | - Emma Slack
- Institute of Microbiology, Department of Biology, ETH Zürich, Zürich, Switzerland. .,Institute of Food, Nutrition and Health, D-HEST, ETH Zürich, Zürich, Switzerland.
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15
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Sulfate Import in Salmonella Typhimurium Impacts Bacterial Aggregation and the Respiratory Burst in Human Neutrophils. Infect Immun 2021; 89:IAI.00701-20. [PMID: 33820814 DOI: 10.1128/iai.00701-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/22/2021] [Indexed: 12/14/2022] Open
Abstract
During enteric salmonellosis, neutrophil-generated reactive oxygen species alter the gut microenvironment, favoring survival of Salmonella Typhimurium. While type 3 secretion system 1 (T3SS-1) and flagellar motility are potent Salmonella Typhimurium agonists of the neutrophil respiratory burst in vitro, neither of these pathways alone is responsible for stimulation of a maximal respiratory burst. To identify Salmonella Typhimurium genes that impact the magnitude of the neutrophil respiratory burst, we performed a two-step screen of defined mutant libraries in coculture with human neutrophils. We first screened Salmonella Typhimurium mutants lacking defined genomic regions and then tested single-gene deletion mutants representing particular regions under selection. A subset of single-gene deletion mutants was selected for further investigation. Mutants in four genes, STM1696 (sapF), STM2201 (yeiE), STM2112 (wcaD), and STM2441 (cysA), induced an attenuated respiratory burst. We linked the altered respiratory burst to reduced T3SS-1 expression and/or altered flagellar motility for two mutants (ΔSTM1696 and ΔSTM2201). The ΔSTM2441 mutant, defective for sulfate transport, formed aggregates in minimal medium and adhered to surfaces in rich medium, suggesting a role for sulfur homeostasis in the regulation of aggregation/adherence. We linked the aggregation/adherence phenotype of the ΔSTM2441 mutant to biofilm-associated protein A and flagellins and hypothesize that aggregation caused the observed reduction in the magnitude of the neutrophil respiratory burst. Our data demonstrate that Salmonella Typhimurium has numerous mechanisms to limit the magnitude of the neutrophil respiratory burst. These data further inform our understanding of how Salmonella may alter human neutrophil antimicrobial defenses.
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16
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Eade CR, Wallen TW, Gates CE, Oliverio CL, Scarbrough BA, Reid AJ, Jorgenson MA, Young KD, Troutman JM. Making the Enterobacterial Common Antigen Glycan and Measuring Its Substrate Sequestration. ACS Chem Biol 2021; 16:691-700. [PMID: 33740380 DOI: 10.1021/acschembio.0c00983] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The enterobacterial common antigen (ECA), a three-sugar repeat unit polysaccharide produced by Enterobacteriaceae family members, impacts bacterial outer membrane permeability, and its biosynthesis affects the glycan landscape of the organism. ECA synthesis impacts the production of other polysaccharides by reducing the availability of shared substrates, the most notable of which is the 55-carbon polyisoprenoid bactoprenyl phosphate (BP), which serves as a carrier for the production of numerous bacterial glycans including ECA, peptidoglycan, O-antigen, and more. Here, using a combination of in vitro enzymatic synthesis and liquid chromatography-mass spectrometry (LC-MS) analysis of bacterial lysates, we provide biochemical evidence for the effect on endogenous polyisoprenoid pools from cell culture that arises from glycan pathway disruption. In this work, we have cloned and expressed each gene involved in ECA repeat unit biosynthesis and reconstituted the pathway in vitro, providing LC-MS characterized standards for the investigation of cellular glycan-linked intermediates and BP. We then generated ECA deficient mutants in genes associated with production of the polysaccharide, which we suspected would accumulate materials identical to our standards. We found that indeed accumulated products from these cells were indistinguishable from our enzymatically prepared standards, and moreover we observed a concomitant decrease in cellular BP levels with each mutant. This work provides the first direct biochemical evidence for the sequestration of BP upon the genetic disruption of glycan biosynthesis pathways in bacteria. This work also provides methods for the direct assessment of both the ECA glycan, and a new understanding of the dynamic interdependence of the bacterial polysaccharide repertoire.
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Affiliation(s)
- Colleen R. Eade
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Timothy W. Wallen
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Claire E. Gates
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
- Biological and Biomedical Sciences Program, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Cassidy L. Oliverio
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Beth A. Scarbrough
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Amanda J. Reid
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Matthew A. Jorgenson
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Kevin D. Young
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
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17
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Kempf F, Menanteau P, Rychlik I, Kubasová T, Trotereau J, Virlogeux‐Payant I, Schaeffer S, Schouler C, Drumo R, Guitton E, Velge P. Gut microbiota composition before infection determines the Salmonella super- and low-shedder phenotypes in chicken. Microb Biotechnol 2020; 13:1611-1630. [PMID: 32639676 PMCID: PMC7415355 DOI: 10.1111/1751-7915.13621] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 12/25/2022] Open
Abstract
Heterogeneity of infection and extreme shedding patterns are common features of animal infectious diseases. Individual hosts that are super-shedders are key targets for control strategies. Nevertheless, the mechanisms associated with the emergence of super-shedders remain largely unknown. During chicken salmonellosis, a high heterogeneity of infection is observed when animal-to-animal cross-contaminations and reinfections are reduced. We hypothesized that unlike super-shedders, low-shedders would be able to block the first Salmonella colonization thanks to a different gut microbiota. The present study demonstrates that (i) axenic and antibiotic-treated chicks are more prone to become super-shedders; (ii) super or low-shedder phenotypes can be acquired through microbiota transfer; (iii) specific gut microbiota taxonomic features determine whether the chicks develop a low- and super-shedder phenotype after Salmonella infection in isolator; (iv) partial protection can be conferred by inoculation of four commensal bacteria prior to Salmonella infection. This study demonstrates the key role plays by gut microbiota composition in the heterogeneity of infection and pave the way for developing predictive biomarkers and protective probiotics.
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Affiliation(s)
- Florent Kempf
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
| | | | - Ivan Rychlik
- Veterinary Research InstituteHudcova 70Brno621 00Czech Republic
| | - Tereza Kubasová
- Veterinary Research InstituteHudcova 70Brno621 00Czech Republic
| | - Jérôme Trotereau
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
| | | | - Samantha Schaeffer
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
- Present address:
INSERM Unité 1162Génomique Fonctionnelle des Tumeurs Solides HépatiquesParisFrance
| | - Catherine Schouler
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
| | - Rosanna Drumo
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
| | - Edouard Guitton
- Plate‐Forme d'Infectiologie ExpérimentaleINRAENouzilly37380France
| | - Philippe Velge
- ISPINRAEUniversité François Rabelais de ToursUMR 1282Nouzilly37380France
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18
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Whitfield C, Williams DM, Kelly SD. Lipopolysaccharide O-antigens-bacterial glycans made to measure. J Biol Chem 2020; 295:10593-10609. [PMID: 32424042 DOI: 10.1074/jbc.rev120.009402] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Indexed: 01/05/2023] Open
Abstract
Lipopolysaccharides are critical components of bacterial outer membranes. The more conserved lipid A part of the lipopolysaccharide molecule is a major element in the permeability barrier imposed by the outer membrane and offers a pathogen-associated molecular pattern recognized by innate immune systems. In contrast, the long-chain O-antigen polysaccharide (O-PS) shows remarkable structural diversity and fulfills a range of functions, depending on bacterial lifestyles. O-PS production is vital for the success of clinically important Gram-negative pathogens. The biological properties and functions of O-PSs are mostly independent of specific structures, but the size distribution of O-PS chains is particularly important in many contexts. Despite the vast O-PS chemical diversity, most are produced in bacterial cells by two assembly strategies, and the different mechanisms employed in these pathways to regulate chain-length distribution are emerging. Here, we review our current understanding of the mechanisms involved in regulating O-PS chain-length distribution and discuss their impact on microbial cell biology.
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Affiliation(s)
- Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Danielle M Williams
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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19
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Linearized Siderophore Products Secreted via MacAB Efflux Pump Protect Salmonella enterica Serovar Typhimurium from Oxidative Stress. mBio 2020; 11:mBio.00528-20. [PMID: 32371597 PMCID: PMC7403778 DOI: 10.1128/mbio.00528-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Nontyphoidal Salmonella bacteria induce a classic inflammatory diarrhea by eliciting a large influx of neutrophils, producing a robust oxidative burst. Despite substantial progress understanding the benefits to the host of the inflammatory response to Salmonella, little is known regarding how Salmonella can simultaneously resist the damaging effects of the oxidative burst. The multidrug efflux pump MacAB is important for survival of oxidative stress both in vitro and during infection. We describe a new pathway used by Salmonella Typhimurium to detoxify extracellular reactive oxygen species using a multidrug efflux pump (MacAB) to secrete a linear siderophore, a metabolite of enterobactin. The natural substrates of many multidrug efflux pumps are unknown, and functional roles of the linear metabolites of enterobactin are unknown. We bring two novel discoveries together to highlight an important mechanism used by Salmonella to survive under the oxidative stress conditions that this organism encounters during the classic inflammatory diarrhea that it also induces. Nontyphoidal salmonellae (NTS) are exposed to reactive oxygen species (ROS) during their residency in the gut. To survive oxidative stress encountered during infection, salmonellae employ several mechanisms. One of these mechanisms involves the multidrug efflux pump MacAB, although the natural substrate of this pump has not been identified. MacAB homologs in pseudomonads secrete products of nonribosomal peptide synthesis (NRPS). In Salmonella enterica serovar Typhimurium, the siderophore enterobactin is produced by NRPS in response to iron starvation and this molecule can be processed into salmochelin and several linear metabolites. We found that Salmonella mutants lacking the key NRPS enzyme EntF are sensitive to peroxide mediated killing and cannot detoxify extracellular H2O2. Moreover, EntF and MacAB function in a common pathway to promote survival of Salmonella during oxidative stress. We further demonstrated that S. Typhimurium secretes siderophores in iron-rich media when peroxide is present and that these MacAB-secreted metabolites participate in protection of bacteria against H2O2. We showed that secretion of anti-H2O2 molecules is independent of the presence of the known siderophore efflux pumps EntS and IroC, well-described efflux systems involved in secretion of enterobactin and salmochelin. Both salmochelin and enterobactin are dispensable for S. Typhimurium protection against ROS; however, linear metabolites of enterobactin produced by esterases IroE and Fes are needed for bacterial survival in peroxide-containing media. We determined that linearized enterobactin trimer protects S. Typhimurium against peroxide-mediated killing in a MacAB-dependent fashion. Thus, we suggest that linearized enterobactin trimer is a natural substrate of MacAB and that its purpose is to detoxify extracellular reactive oxygen species.
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20
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Medrano-Soto A, Ghazi F, Hendargo KJ, Moreno-Hagelsieb G, Myers S, Saier MH. Expansion of the Transporter-Opsin-G protein-coupled receptor superfamily with five new protein families. PLoS One 2020; 15:e0231085. [PMID: 32320418 PMCID: PMC7176098 DOI: 10.1371/journal.pone.0231085] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/17/2020] [Indexed: 02/06/2023] Open
Abstract
Here we provide bioinformatic evidence that the Organo-Arsenical Exporter (ArsP), Endoplasmic Reticulum Retention Receptor (KDELR), Mitochondrial Pyruvate Carrier (MPC), L-Alanine Exporter (AlaE), and the Lipid-linked Sugar Translocase (LST) protein families are members of the Transporter-Opsin-G Protein-coupled Receptor (TOG) Superfamily. These families share domains homologous to well-established TOG superfamily members, and their topologies of transmembranal segments (TMSs) are compatible with the basic 4-TMS repeat unit characteristic of this Superfamily. These repeat units tend to occur twice in proteins as a result of intragenic duplication events, often with subsequent gain/loss of TMSs in many superfamily members. Transporters within the ArsP family allow microbial pathogens to expel toxic arsenic compounds from the cell. Members of the KDELR family are involved in the selective retrieval of proteins that reside in the endoplasmic reticulum. Proteins of the MPC family are involved in the transport of pyruvate into mitochondria, providing the organelle with a major oxidative fuel. Members of family AlaE excrete L-alanine from the cell. Members of the LST family are involved in the translocation of lipid-linked glucose across the membrane. These five families substantially expand the range of substrates of transport carriers in the superfamily, although KDEL receptors have no known transport function. Clustering of protein sequences reveals the relationships among families, and the resulting tree correlates well with the degrees of sequence similarity documented between families. The analyses and programs developed to detect distant relatedness, provide insights into the structural, functional, and evolutionary relationships that exist between families of the TOG superfamily, and should be of value to many other investigators.
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Affiliation(s)
- Arturo Medrano-Soto
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Faezeh Ghazi
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Kevin J. Hendargo
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | | | - Scott Myers
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Milton H. Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
- * E-mail:
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21
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Wang M, Qazi IH, Wang L, Zhou G, Han H. Salmonella Virulence and Immune Escape. Microorganisms 2020; 8:microorganisms8030407. [PMID: 32183199 PMCID: PMC7143636 DOI: 10.3390/microorganisms8030407] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/02/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023] Open
Abstract
Salmonella genus represents the most common foodborne pathogens causing morbidity, mortality, and burden of disease in all regions of the world. The introduction of antimicrobial agents and Salmonella-specific phages has been considered as an effective intervention strategy to reduce Salmonella contamination. However, data from the United States, European countries, and low- and middle-income countries indicate that Salmonella cases are still a commonly encountered cause of bacterial foodborne diseases globally. The control programs have not been successful and even led to the emergence of some multidrug-resistant Salmonella strains. It is known that the host immune system is able to effectively prevent microbial invasion and eliminate microorganisms. However, Salmonella has evolved mechanisms of resisting host physical barriers and inhibiting subsequent activation of immune response through their virulence factors. There has been a high interest in understanding how Salmonella interacts with the host. Therefore, in the present review, we characterize the functions of Salmonella virulence genes and particularly focus on the mechanisms of immune escape in light of evidence from the emerging mainstream literature.
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Affiliation(s)
- Mengyao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Izhar Hyder Qazi
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China;
- Department of Veterinary Anatomy and Histology, Shaheed Benazir Bhutto University of Veterinary and Animal Sciences, Sakrand 67210, Pakistan
| | - Linli Wang
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Guangbin Zhou
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China;
- Correspondence: (H.H.); (G.Z.)
| | - Hongbing Han
- Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (M.W.); (L.W.)
- Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
- Correspondence: (H.H.); (G.Z.)
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22
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Abstract
Lipopolysaccharides are a major component of the outer membrane in Gram-negative bacteria. They are composed of a conserved lipid structure that is embedded in the outer leaflet of the outer membrane and a polysaccharide known as the O-antigen. O-antigens are highly variable in structure across strains of a species and are crucial to a bacterium’s interactions with its environment. They constitute the first line of defense against both the immune system and bacteriophage infections and have been shown to mediate antimicrobial resistance. The significance of our research is in identifying the metabolic and genetic differences within and across O-antigen groups in Salmonella strains. Our effort constitutes a first step toward characterizing the O-antigen metabolic network across Gram-negative organisms and a comprehensive overview of genetic variations in Salmonella. O-antigens are glycopolymers in lipopolysaccharides expressed on the cell surface of Gram-negative bacteria. Variability in the O-antigen structure constitutes the basis for the establishment of the serotyping schema. We pursued a two-pronged approach to define the basis for O-antigen structural diversity. First, we developed a bottom-up systems biology approach to O-antigen metabolism by building a reconstruction of Salmonella O-antigen biosynthesis and used it to (i) update 410 existing Salmonella strain-specific metabolic models, (ii) predict a strain’s serogroup and its O-antigen glycan synthesis capability (yielding 98% agreement with experimental data), and (iii) extend our workflow to more than 1,400 Gram-negative strains. Second, we used a top-down pangenome analysis to elucidate the genetic basis for intraserogroup O-antigen structural variations. We assembled a database of O-antigen gene islands from over 11,000 sequenced Salmonella strains, revealing (i) that gene duplication, pseudogene formation, gene deletion, and bacteriophage insertion elements occur ubiquitously across serogroups; (ii) novel serotypes in the group O:4 B2 variant, as well as an additional genotype variant for group O:4, and (iii) two novel O-antigen gene islands in understudied subspecies. We thus comprehensively defined the genetic basis for O-antigen diversity.
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Crittenden CM, Escobar EE, Williams PE, Sanders JD, Brodbelt JS. Characterization of Antigenic Oligosaccharides from Gram-Negative Bacteria via Activated Electron Photodetachment Mass Spectrometry. Anal Chem 2019; 91:4672-4679. [PMID: 30844257 DOI: 10.1021/acs.analchem.9b00048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Lipooligosaccharides (LOS), composed of hydrophilic oligosaccharides and hydrophobic lipid A domains, are found on the outer membranes of Gram-negative bacteria. Here we report the characterization of deacylated LOS of LPS by activated-electron photodetachment mass spectrometry. Collision induced dissociation (CID) of these phosphorylated oligosaccharides produces simple MS/MS spectra with most fragment ions arising from cleavages near the reducing end of the molecule where the phosphate groups are located. In contrast, 193 nm ultraviolet photodissociation (UVPD) generates a wide array of product ions throughout the oligosaccharide including cross-ring fragments that illuminate the branching patterns. However, there are also product ions that are redundant or uninformative, resulting in more congested spectra that complicate interpretation. In this work, a hybrid UVPD-CID approach known as activated-electron photodetachment (a-EPD) affords less congested spectra than UVPD alone and richer fragmentation patterns than CID alone. a-EPD combines UVPD of negatively charged oligosaccharides to yield abundant charge-reduced radical ions which are subsequently interrogated by collisional activation. CID of the charge-reduced precursors results in extensive fragmentation throughout the backbone of the oligosaccharide. This hybridized a-EPD approach was employed to characterize the structure and branching pattern of deacylated LOS of E. coli.
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Affiliation(s)
| | - Edwin E Escobar
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Peggy E Williams
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - James D Sanders
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Jennifer S Brodbelt
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
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24
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Zhi Y, Narindoshvili T, Bogomolnaya L, Talamantes M, El Saadi A, Andrews-Polymenis H, Raushel FM. Deciphering the Enzymatic Function of the Bovine Enteric Infection-Related Protein YfeJ from Salmonella enterica Serotype Typhimurium. Biochemistry 2019; 58:1236-1245. [PMID: 30715856 DOI: 10.1021/acs.biochem.8b01283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Non-typhoidal Salmonella can colonize the gastrointestinal system of cattle and can also cause significant food-borne disease in humans. The use of a library of single-gene deletions in Salmonella enterica serotype Typhimurium allowed identification of several proteins that are under selection in the intestine of cattle. STM2437 ( yfeJ) encodes one of these proteins, and it is currently annotated as a type I glutamine amidotransferase. STM2437 was purified to homogeneity, and its catalytic properties with a wide range of γ-glutamyl derivatives were determined. The catalytic efficiency toward the hydrolysis of l-glutamine was extremely weak with a kcat/ Km value of 20 M-1 s-1. γ-l-Glutamyl hydroxamate was identified as the best substrate for STM2437, with a kcat/ Km value of 9.6 × 104 M-1 s-1. A homology model of STM2437 was constructed on the basis of the known crystal structure of a protein of unknown function (Protein Data Bank entry 3L7N ), and γ-l-glutamyl hydroxamate was docked into the active site based on the binding of l-glutamine in the active site of carbamoyl phosphate synthetase. Acivicin was shown to inactivate the enzyme by reaction with the active site cysteine residue and the subsequent loss of HCl. Mutation of Cys91 to serine completely abolished catalytic activity. Inactivation of STM2437 did not affect the ability of this strain to colonize mice, but it inhibited the growth of S. enterica Typhimurium in bacteriologic media containing γ-l-glutamyl hydroxamate.
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Affiliation(s)
- Yuan Zhi
- Department of Biochemistry and Biophysics , Texas A&M University , College Station , Texas 77843 , United States
| | - Tamari Narindoshvili
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
| | - Lydia Bogomolnaya
- Department of Microbial Pathogenesis and Immunology, College of Medicine , Texas A&M University System Health Science Center , Bryan , Texas 77807 , United States
| | - Marissa Talamantes
- Department of Microbial Pathogenesis and Immunology, College of Medicine , Texas A&M University System Health Science Center , Bryan , Texas 77807 , United States
| | - Ahmed El Saadi
- Department of Microbial Pathogenesis and Immunology, College of Medicine , Texas A&M University System Health Science Center , Bryan , Texas 77807 , United States
| | - Helene Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, College of Medicine , Texas A&M University System Health Science Center , Bryan , Texas 77807 , United States
| | - Frank M Raushel
- Department of Biochemistry and Biophysics , Texas A&M University , College Station , Texas 77843 , United States.,Department of Chemistry , Texas A&M University , College Station , Texas 77843 , United States
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25
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Gal-Mor O. Persistent Infection and Long-Term Carriage of Typhoidal and Nontyphoidal Salmonellae. Clin Microbiol Rev 2019; 32:e00088-18. [PMID: 30487167 PMCID: PMC6302356 DOI: 10.1128/cmr.00088-18] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The ability of pathogenic bacteria to affect higher organisms and cause disease is one of the most dramatic properties of microorganisms. Some pathogens can establish transient colonization only, but others are capable of infecting their host for many years or even for a lifetime. Long-term infection is called persistence, and this phenotype is fundamental for the biology of important human pathogens, including Helicobacter pylori, Mycobacterium tuberculosis, and Salmonella enterica Both typhoidal and nontyphoidal serovars of the species Salmonella enterica can cause persistent infection in humans; however, as these two Salmonella groups cause clinically distinct diseases, the characteristics of their persistent infections in humans differ significantly. Here, following a general summary of Salmonella pathogenicity, host specificity, epidemiology, and laboratory diagnosis, I review the current knowledge about Salmonella persistence and discuss the relevant epidemiology of persistence (including carrier rate, duration of shedding, and host and pathogen risk factors), the host response to Salmonella persistence, Salmonella genes involved in this lifestyle, as well as genetic and phenotypic changes acquired during prolonged infection within the host. Additionally, I highlight differences between the persistence of typhoidal and nontyphoidal Salmonella strains in humans and summarize the current gaps and limitations in our understanding, diagnosis, and curing of persistent Salmonella infections.
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Affiliation(s)
- Ohad Gal-Mor
- Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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26
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Sánchez-Romero MA, Casadesús J. Contribution of SPI-1 bistability to Salmonella enterica cooperative virulence: insights from single cell analysis. Sci Rep 2018; 8:14875. [PMID: 30291285 PMCID: PMC6173691 DOI: 10.1038/s41598-018-33137-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/20/2018] [Indexed: 11/25/2022] Open
Abstract
Salmonella enterica pathogenicity island 1 (SPI-1) is a gene cluster that encodes a type III secretion system and effectors involved in epithelial cell invasion. SPI-1 undergoes bistable expression, with concomitant formation of SPI-1ON and SPI-1OFF lineages. This study describes single cell analysis of SP1-1 bistability and epithelial cell invasion, and reports the unsuspected observation that optimal invasion of epithelial cells requires the presence of both SPI-1ON and SPI-1OFF subpopulations. The contribution of SPI-1OFF cells to optimal invasion may rely on their ability to invade epithelial cells if a SPI-1ON subpopulation is present. In fact, Salmonella SPI-1 mutants are also able to invade epithelial cells in the presence of SPI-1ONSalmonellae, a phenomenon described in the 1990’s by Galán and co-workers. Invasion by SPI-1OFF cells does not seem to involve a diffusible factor. A small number of SPI-1ON cells is sufficient to endow the bacterial population with invasion capacity, a feature that may permit host colonization regardless of the bottlenecks encountered by Salmonella populations inside animals.
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Affiliation(s)
| | - Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080, Sevilla, Spain
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27
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Jaslow SL, Gibbs KD, Fricke WF, Wang L, Pittman KJ, Mammel MK, Thaden JT, Fowler VG, Hammer GE, Elfenbein JR, Ko DC. Salmonella Activation of STAT3 Signaling by SarA Effector Promotes Intracellular Replication and Production of IL-10. Cell Rep 2018; 23:3525-3536. [PMID: 29924996 PMCID: PMC6314477 DOI: 10.1016/j.celrep.2018.05.072] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 03/24/2018] [Accepted: 05/21/2018] [Indexed: 12/23/2022] Open
Abstract
Salmonella enterica is an important foodborne pathogen that uses secreted effector proteins to manipulate host pathways to facilitate survival and dissemination. Different S. enterica serovars cause disease syndromes ranging from gastroenteritis to typhoid fever and vary in their effector repertoire. We leveraged this natural diversity to identify stm2585, here designated sarA (Salmonella anti-inflammatory response activator), as a Salmonella effector that induces production of the anti-inflammatory cytokine IL-10. RNA-seq of cells infected with either ΔsarA or wild-type S. Typhimurium revealed that SarA activates STAT3 transcriptional targets. Consistent with this, SarA is necessary and sufficient for STAT3 phosphorylation, STAT3 inhibition blocks IL-10 production, and SarA and STAT3 interact by co-immunoprecipitation. These effects of SarA contribute to intracellular replication in vitro and bacterial load at systemic sites in mice. Our results demonstrate the power of using comparative genomics for identifying effectors and that Salmonella has evolved mechanisms for activating an important anti-inflammatory pathway.
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Affiliation(s)
- Sarah L Jaslow
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Kyle D Gibbs
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - W Florian Fricke
- Department of Nutrigenomics, University of Hohenheim, Stuttgart, Germany
| | - Liuyang Wang
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Kelly J Pittman
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Mark K Mammel
- Division of Molecular Biology, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA
| | - Joshua T Thaden
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Vance G Fowler
- Division of Infectious Diseases, Department of Medicine, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Gianna E Hammer
- Department of Immunology, School of Medicine, Duke University, Durham, NC 27710, USA
| | - Johanna R Elfenbein
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Dennis C Ko
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC 27710, USA; Division of Infectious Diseases, Department of Medicine, School of Medicine, Duke University, Durham, NC 27710, USA.
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28
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García-Pastor L, Puerta-Fernández E, Casadesús J. Bistability and phase variation in Salmonella enterica. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:752-758. [PMID: 29369799 DOI: 10.1016/j.bbagrm.2018.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 01/09/2018] [Indexed: 11/18/2022]
Abstract
Cell-to-cell differences in bacterial gene expression can merely reflect the occurrence of noise. In certain cases, however, heterogeneous gene expression is a programmed event that results in bistable expression. If bistability is heritable, bacterial lineages are formed. When programmed bistability is reversible, the phenomenon is known as phase variation. In certain cases, bistability is controlled by genetic mechanisms (e. g., DNA rearrangement). In other cases, bistability has epigenetic origin. A robust epigenetic mechanism for the formation of bacterial lineages is the formation of heritable DNA methylation patterns. However, bistability can also arise upon propagation of gene expression patterns by feedback loops that are stable upon cell division. This review describes examples of bistability and phase variation in Salmonella enterica and discusses their adaptive value, sometimes in a speculative manner.
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Affiliation(s)
- Lucía García-Pastor
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain
| | - Elena Puerta-Fernández
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain
| | - Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain.
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29
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Kohli N, Crisp Z, Riordan R, Li M, Alaniz RC, Jayaraman A. The microbiota metabolite indole inhibits Salmonella virulence: Involvement of the PhoPQ two-component system. PLoS One 2018; 13:e0190613. [PMID: 29342189 PMCID: PMC5771565 DOI: 10.1371/journal.pone.0190613] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 12/18/2017] [Indexed: 02/02/2023] Open
Abstract
The microbial community present in the gastrointestinal tract is an important component of the host defense against pathogen infections. We previously demonstrated that indole, a microbial metabolite of tryptophan, reduces enterohemorrhagic Escherichia coli O157:H7 attachment to intestinal epithelial cells and biofilm formation, suggesting that indole may be an effector/attenuator of colonization for a number of enteric pathogens. Here, we report that indole attenuates Salmonella Typhimurium (Salmonella) virulence and invasion as well as increases resistance to colonization in host cells. Indole-exposed Salmonella colonized mice less effectively compared to solvent-treated controls, as evident by competitive index values less than 1 in multiple organs. Indole-exposed Salmonella demonstrated 160-fold less invasion of HeLa epithelial cells and 2-fold less invasion of J774A.1 macrophages compared to solvent-treated controls. However, indole did not affect Salmonella intracellular survival in J774A.1 macrophages suggesting that indole primarily affects Salmonella invasion. The decrease in invasion was corroborated by a decrease in expression of multiple Salmonella Pathogenicity Island-1 (SPI-1) genes. We also identified that the effect of indole was mediated by both PhoPQ-dependent and independent mechanisms. Indole also synergistically enhanced the inhibitory effect of a short chain fatty acid cocktail on SPI-1 gene expression. Lastly, indole-treated HeLa cells were 70% more resistant to Salmonella invasion suggesting that indole also increases resistance of epithelial cells to colonization. Our results demonstrate that indole is an important microbiota metabolite that has direct anti-infective effects on Salmonella and host cells, revealing novel mechanisms of pathogen colonization resistance.
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Affiliation(s)
- Nandita Kohli
- Department of Chemical Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Zeni Crisp
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, United States of America
| | - Rebekah Riordan
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, United States of America
| | - Michael Li
- Department of Chemical Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Robert C Alaniz
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, United States of America
| | - Arul Jayaraman
- Department of Chemical Engineering, Texas A&M University, College Station, Texas, United States of America.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, United States of America
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30
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Yang HJ, Bogomolnaya L, McClelland M, Andrews-Polymenis H. De novo pyrimidine synthesis is necessary for intestinal colonization of Salmonella Typhimurium in chicks. PLoS One 2017; 12:e0183751. [PMID: 29040285 PMCID: PMC5644981 DOI: 10.1371/journal.pone.0183751] [Citation(s) in RCA: 8] [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: 06/20/2017] [Accepted: 08/10/2017] [Indexed: 11/18/2022] Open
Abstract
pyrE (STM3733) encodes orotate phosphoribosyltransferase (OPRTase; EC 2.4.2.10), the fifth enzyme of the de novo pyrimidine biosynthetic pathway. We identified a ΔpyrE mutant as under selection in screening of a Salmonella mutant library in 4-day old chicks. Here, we confirm that a ΔpyrE mutant colonizes 4-day old chicks poorly in competitive infection with isogenic wild type, and that the ability of this mutant to colonize chicks could be restored by providing a copy of pyrE in trans. We further show that our ΔpyrE mutant grows poorly in nutrient poor conditions in vitro, and that the ability of this mutant to grow is restored, both in vitro and in chicks, when precursors to the pyrimidine salvage pathway were provided. This finding suggests that the environment in the chick intestine during our infections lacks sufficient precursors of the pyrimidine salvage pathway to support Salmonella growth. Finally, we show that the colonization defect of a ΔpyrE mutant during infection occurs in to chicks, but not in CBA/J mice or ligated ileal loops in calves. Our data suggest that de novo pyrimidine synthesis is necessary for colonization of Salmonella Typhimurium in the chick, and that the salvage pathway is not used in this niche.
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Affiliation(s)
- Hee-Jeong Yang
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
| | - Lydia Bogomolnaya
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, and Pathology and Laboratory Medicine, University of California, Irvine, CA, United States of America
| | - Helene Andrews-Polymenis
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M University System Health Science Center, Bryan, TX, United States of America
- * E-mail:
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31
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Ilyas B, Tsai CN, Coombes BK. Evolution of Salmonella-Host Cell Interactions through a Dynamic Bacterial Genome. Front Cell Infect Microbiol 2017; 7:428. [PMID: 29034217 PMCID: PMC5626846 DOI: 10.3389/fcimb.2017.00428] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
Salmonella Typhimurium has a broad arsenal of genes that are tightly regulated and coordinated to facilitate adaptation to the various host environments it colonizes. The genome of Salmonella Typhimurium has undergone multiple gene acquisition events and has accrued changes in non-coding DNA that have undergone selection by regulatory evolution. Together, at least 17 horizontally acquired pathogenicity islands (SPIs), prophage-associated genes, and changes in core genome regulation contribute to the virulence program of Salmonella. Here, we review the latest understanding of these elements and their contributions to pathogenesis, emphasizing the regulatory circuitry that controls niche-specific gene expression. In addition to an overview of the importance of SPI-1 and SPI-2 to host invasion and colonization, we describe the recently characterized contributions of other SPIs, including the antibacterial activity of SPI-6 and adhesion and invasion mediated by SPI-4. We further discuss how these fitness traits have been integrated into the regulatory circuitry of the bacterial cell through cis-regulatory evolution and by a careful balance of silencing and counter-silencing by regulatory proteins. Detailed understanding of regulatory evolution within Salmonella is uncovering novel aspects of infection biology that relate to host-pathogen interactions and evasion of host immunity.
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Affiliation(s)
- Bushra Ilyas
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Caressa N Tsai
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Brian K Coombes
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
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32
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Signal transduction pathway mediated by the novel regulator LoiA for low oxygen tension induced Salmonella Typhimurium invasion. PLoS Pathog 2017; 13:e1006429. [PMID: 28575106 PMCID: PMC5476282 DOI: 10.1371/journal.ppat.1006429] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/19/2017] [Accepted: 05/23/2017] [Indexed: 02/03/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major intestinal pathogen of both humans and animals. Salmonella pathogenicity island 1 (SPI-1)-encoded virulence genes are required for S. Typhimurium invasion. While oxygen (O2) limitation is an important signal for SPI-1 induction under host conditions, how the signal is received and integrated to the central SPI-1 regulatory system in S. Typhimurium is not clear. Here, we report a signal transduction pathway that activates SPI-1 expression in response to low O2. A novel regulator encoded within SPI-14 (STM14_1008), named LoiA (low oxygen induced factor A), directly binds to the promoter and activates transcription of hilD, leading to the activation of hilA (the master activator of SPI-1). Deletion of loiA significantly decreased the transcription of hilA, hilD and other representative SPI-1 genes (sipB, spaO, invH, prgH and invF) under low O2 conditions. The response of LoiA to the low O2 signal is mediated by the ArcB/ArcA two-component system. Deletion of either arcA or arcB significantly decreased transcription of loiA under low O2 conditions. We also confirmed that SPI-14 contributes to S. Typhimurium virulence by affecting invasion, and that loiA is the virulence determinant of SPI-14. Mice infection assays showed that S. Typhimurium virulence was severely attenuated by deletion of either the entire SPI-14 region or the single loiA gene after oral infection, while the virulence was not affected by either deletion after intraperitoneal infection. The signal transduction pathway described represents an important mechanism for S. Typhimurium to sense and respond to low O2 conditions of the host intestinal tract for invasion. SPI-14-encoded loiA is an essential element of this pathway that integrates the low O2 signal into the SPI-1 regulatory system. Acquisition of SPI-14 is therefore crucial for the evolution of S. Typhimurium as an intestinal pathogen. Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major intestinal pathogen of both humans and animals. Salmonella pathogenicity island 1 (SPI-1) is required for host cell invasion by S. Typhimurium. Expression of SPI-1 genes is induced by low oxygen (O2) tension under host conditions, but the relevant regulatory mechanisms are not clear. Here, we report a low O2-induced signal transduction pathway for the activation of SPI-1 expression in S. Typhimurium. A novel regulator, STM14_1008 (named LoiA), encoded within SPI-14 directly activates hilD, which in turn activates hilA (the master activator of SPI-1), and thus other SPI-1 genes under O2-limited conditions. The response of LoiA to the low O2 signal is mediated by the ArcB/ArcA two-component system. We also confirmed that SPI-14 contributes to S. Typhimurium virulence by affecting invasion, with loiA as the virulence determinant. This novel SPI-1 activation pathway can be used by S. Typhimurium to sense and respond to low O2 conditions of the host intestinal tract for invasion. Acquisition of SPI-14 is therefore very important for the evolution of S. Typhimurium virulence by providing an essential component of this pathway, loiA.
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33
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Salmonella enterica Serovar Typhi Lipopolysaccharide O-Antigen Modification Impact on Serum Resistance and Antibody Recognition. Infect Immun 2017; 85:IAI.01021-16. [PMID: 28167670 PMCID: PMC5364305 DOI: 10.1128/iai.01021-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/30/2017] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (gtr) operons acquired by horizontal gene transfer. Here we investigate the role of two gtr operons that we identified in the S. Typhi genome. Strains were engineered to express specific gtr operons. Full chemical analysis of the O-antigens of these strains identified gtr-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating gtr operon uniform in the population. In contrast, the expression of the acetylating gtrC gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the Salmonellagtr repertoire may confound the protective efficacy of broad-ranging Salmonella lipopolysaccharide conjugate vaccines.
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Elfenbein JR, Knodler LA, Schaeffer AR, Faber F, Bäumler AJ, Andrews-Polymenis HL. A Salmonella Regulator Modulates Intestinal Colonization and Use of Phosphonoacetic Acid. Front Cell Infect Microbiol 2017; 7:69. [PMID: 28361036 PMCID: PMC5351497 DOI: 10.3389/fcimb.2017.00069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 02/23/2017] [Indexed: 11/21/2022] Open
Abstract
Many microorganisms produce phosphonates, molecules characterized by stable carbon-phosphorus bonds that store phosphorus or act as antimicrobials. The role of phosphonates in the marine biosphere is well characterized but the role of these molecules in the intestine is poorly understood. Salmonella enterica uses its virulence factors to influence the host immune response to compete with the host and normal microflora for nutrients. Salmonella cannot produce phosphonates but encodes the enzymes to use them suggesting that it is exposed to phosphonates during its life cycle. The role of phosphonates during enteric salmonellosis is unexplored. We have previously shown that STM3602, encoding a putative regulator of phosphonate metabolism, is needed for colonization in calves. Here, we report that the necessity of STM3602 in colonization of the murine intestine results from multiple factors. STM3602 is needed for full activation of the type-3 secretion system-1 and for optimal invasion of epithelial cells. The ΔSTM3602 mutant grows poorly in phosphonoacetic acid (PA) as the sole phosphorus source, but can use 2-aminoethylphosphonate. PhnA, an enzyme required for PA breakdown, is not controlled by STM3602 suggesting an additional mechanism for utilization of PA in S. Typhimurium. Finally, the requirement of STM3602 for intestinal colonization differs depending on the composition of the microflora. Our data suggest that STM3602 has multiple regulatory targets that are necessary for survival within the microbial community in the intestine. Determination of the members of the STM3602 regulon may illuminate new pathways needed for colonization of the host.
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Affiliation(s)
- Johanna R. Elfenbein
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State UniversityRaleigh, NC, USA
| | - Leigh A. Knodler
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State UniversityPullman, WA, USA
| | - Allison R. Schaeffer
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
| | - Franziska Faber
- Department of Medial Microbiology and Immunology, School of Medicine, University of California DavisDavis, CA, USA
| | - Andreas J. Bäumler
- Department of Medial Microbiology and Immunology, School of Medicine, University of California DavisDavis, CA, USA
| | - Helene L. Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University Health Science CenterBryan, TX, USA
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Shirshikova TV, Morozova OV, Kamaletdinova LK, Sharipova MR, Bogomolnaya LM. Generalized Bacteriophage Transduction in Serratia marcescens. BIONANOSCIENCE 2016. [DOI: 10.1007/s12668-016-0268-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Schmidt A, Rabsch W, Broeker NK, Barbirz S. Bacteriophage tailspike protein based assay to monitor phase variable glucosylations in Salmonella O-antigens. BMC Microbiol 2016; 16:207. [PMID: 27604475 PMCID: PMC5015238 DOI: 10.1186/s12866-016-0826-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 08/31/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Non-typhoid Salmonella Typhimurium (S. Typhimurium) accounts for a high number of registered salmonellosis cases, and O-serotyping is one important tool for monitoring epidemiology and spread of the disease. Moreover, variations in glucosylated O-antigens are related to immunogenicity and spread in the host. However, classical autoagglutination tests combined with the analysis of specific genetic markers cannot always reliably register phase variable glucose modifications expressed on Salmonella O-antigens and additional tools to monitor O-antigen glucosylation phenotypes of S. Typhimurium would be desirable. RESULTS We developed a test for the phase variable O-antigen glucosylation state of S. Typhimurium using the tailspike proteins (TSP) of Salmonella phages 9NA and P22. We used this ELISA like tailspike adsorption (ELITA) assay to analyze a library of 44 Salmonella strains. ELITA was successful in discriminating strains that carried glucose 1-6 linked to the galactose of O-polysaccharide backbone (serotype O1) from non-glucosylated strains. This was shown by O-antigen compositional analyses of the respective strains with mass spectrometry and capillary electrophoresis. The ELITA test worked rapidly in a microtiter plate format and was highly O-antigen specific. Moreover, TSP as probes could also detect glucosylated strains in flow cytometry and distinguish multiphasic cultures differing in their glucosylation state. CONCLUSIONS Tailspike proteins contain large binding sites with precisely defined specificities and are therefore promising tools to be included in serotyping procedures as rapid serotyping agents in addition to antibodies. In this study, 9NA and P22TSP as probes could specifically distinguish glucosylation phenotypes of Salmonella on microtiter plate assays and in flow cytometry. This opens the possibility for flow sorting of cell populations for subsequent genetic analyses or for monitoring phase variations during large scale O-antigen preparations necessary for vaccine production.
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Affiliation(s)
- Andreas Schmidt
- Physikalische Biochemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Golm, 14476, Germany
| | - Wolfgang Rabsch
- National Reference Centre for Salmonella and other Bacterial Enterics, Robert Koch Institute, Burgstraße 37, Wernigerode, 38855, Germany
| | - Nina K Broeker
- Physikalische Biochemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Golm, 14476, Germany
| | - Stefanie Barbirz
- Physikalische Biochemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Golm, 14476, Germany.
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Cureau N, AlJahdali N, Vo N, Carbonero F. Epigenetic mechanisms in microbial members of the human microbiota: current knowledge and perspectives. Epigenomics 2016; 8:1259-73. [DOI: 10.2217/epi-2016-0057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human microbiota and epigenetic processes have both been shown to play a crucial role in health and disease. However, there is extremely scarce information on epigenetic modulation of microbiota members except for a few pathogens. Mainly DNA adenine methylation has been described extensively in modulating the virulence of pathogenic bacteria in particular. It would thus appear likely that such mechanisms are widespread for most bacterial members of the microbiota. This review will present briefly the current knowledge on epigenetic processes in bacteria, give examples of known methylation processes in microbial members of the human microbiota and summarize the knowledge on regulation of host epigenetic processes by the human microbiota.
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Affiliation(s)
- Natacha Cureau
- Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA
| | - Nesreen AlJahdali
- Cellular and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72704, USA
| | - Nguyen Vo
- Cellular and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72704, USA
| | - Franck Carbonero
- Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA
- Cellular and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72704, USA
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Use of bacteriophage to target bacterial surface structures required for virulence: a systematic search for antibiotic alternatives. Curr Genet 2016; 62:753-757. [PMID: 27113766 DOI: 10.1007/s00294-016-0603-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 04/11/2016] [Indexed: 01/21/2023]
Abstract
Bacteriophages (phage) that infect pathogenic bacteria often attach to surface receptors that are coincidentally required for virulence. Receptor loss or modification through mutation renders mutants both attenuated and phage resistant. Such attenuated mutants frequently have no apparent laboratory growth defects, but in the host, they fail to exhibit properties needed to produce disease such as mucosal colonization or survival within professional phagocytic cells. The connection between attenuation and phage resistance has been exploited in experimental demonstrations of phage therapy. In such experiments, phage resistant mutants that arise naturally during therapy are inconsequential because of their attenuated status. A more contemporary approach to exploiting this connection involves identifying small effector molecules, identified in high-throughput screens, that inhibit one or more of the steps needed to produce a functioning phage receptor. Since such biosynthetic steps are unique to bacteria, inhibitors can be utilized therapeutically, in lieu of antibiotics. Also, since the inhibitor is specific to a particular bacterium or group of bacteria, no off-target resistance is generated in the host's commensal bacterial population. This brief review covers examples of how mutations that confer phage resistance produce attenuation, and how this coincidental relationship can be exploited in the search for the next generation of therapeutic agents for bacterial diseases.
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Spears PA, Havell EA, Hamrick TS, Goforth JB, Levine AL, Abraham ST, Heiss C, Azadi P, Orndorff PE. Listeria monocytogenes wall teichoic acid decoration in virulence and cell-to-cell spread. Mol Microbiol 2016; 101:714-30. [PMID: 26871418 DOI: 10.1111/mmi.13353] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2016] [Indexed: 12/11/2022]
Abstract
Wall teichoic acid (WTA) comprises a class of glycopolymers covalently attached to the peptidoglycan of gram positive bacteria. In Listeria monocytogenes, mutations that prevent addition of certain WTA decorating sugars are attenuating. However, the steps required for decoration and the pathogenic process interrupted are not well described. We systematically examined the requirement for WTA galactosylation in a mouse oral-virulent strain by first creating mutations in four genes whose products conferred resistance to a WTA-binding bacteriophage. WTA biochemical and structural studies indicated that galactosylated WTA was directly required for bacteriophage adsorption and that mutant WTA lacked appreciable galactose in all except one mutant - which retained a level ca. 7% of the parent. All mutants were profoundly attenuated in orally infected mice and were impaired in cell-to-cell spread in vitro. Confocal microscopy of cytosolic mutants revealed that all expressed ActA on their cell surface and formed actin tails with a frequency similar to the parent. However, the mutant tails were significantly shorter - suggesting a defect in actin based motility. Roles for the gene products in WTA galactosylation are proposed. Identification and interruption of WTA decoration pathways may provide a general strategy to discover non-antibiotic therapeutics for gram positive infections. © 2016 John Wiley & Sons Ltd.
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Affiliation(s)
- Patricia A Spears
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA
| | - Edward A Havell
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA
| | - Terri S Hamrick
- Department of Microbiology and Immunology, School of Osteopathic Medicine, Campbell University, Buies Creek, NC, 27506, USA
| | - John B Goforth
- Department of Microbiology and Immunology, School of Osteopathic Medicine, Campbell University, Buies Creek, NC, 27506, USA
| | - Alexandra L Levine
- Department of Microbiology and Immunology, School of Osteopathic Medicine, Campbell University, Buies Creek, NC, 27506, USA
| | - S Thomas Abraham
- Department of Pharmaceutical Sciences, College of Pharmacy & Health Sciences, Campbell University, Buies Creek, NC, 27506, USA
| | - Christian Heiss
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602, USA
| | - Paul E Orndorff
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA
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Mann E, Ovchinnikova OG, King JD, Whitfield C. Bacteriophage-mediated Glucosylation Can Modify Lipopolysaccharide O-Antigens Synthesized by an ATP-binding Cassette (ABC) Transporter-dependent Assembly Mechanism. J Biol Chem 2015; 290:25561-70. [PMID: 26330553 DOI: 10.1074/jbc.m115.660803] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Indexed: 11/06/2022] Open
Abstract
Lysogenic bacteriophages may encode enzymes that modify the structures of lipopolysaccharide O-antigen glycans, altering the structure of the bacteriophage receptor and resulting in serotype conversion. This can enhance virulence and has implications for antigenic diversity and vaccine development. Side chain glucosylation is a common modification strategy found in a number of bacterial species. To date, glucosylation has only been observed in O-antigens synthesized by Wzy-dependent pathways, one of the two most prevalent O-antigen synthesis systems. Here we exploited a heterologous system to study the glucosylation potential of a model O-antigen produced in an ATP-binding cassette (ABC) transporter-dependent system. Although O-antigen production is cryptic in Escherichia coli K-12, because of a mutation in the synthesis genes, it possesses a prophage glucosylation cluster, which modifies the GlcNAc residue in an α-l-Rha-(1→3)-d-GlcNAc motif found in the original O16 antigen. Raoultella terrigena ATCC 33257 produces an O-antigen possessing the same disaccharide motif, but its assembly uses an ABC transporter-dependent system. E. coli harboring the R. terrigena O-antigen biosynthesis genes produced an O-antigen displaying reduced reactivity toward antisera raised against the native R. terrigena repeat structure, indicative of an altered chemical structure. Structural determination using NMR revealed the addition of glucose side chains to the repeat units. O-antigen modification was dependent on a functional ABC transporter, consistent with modification in the periplasm, and was eliminated by deletion of the glucosylation genes from the E. coli chromosome, restoring native level antisera sensitivity and structure. There are therefore no intrinsic mechanistic barriers for bacteriophage-mediated O-antigen glucosylation in ABC transporter-dependent pathways.
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Affiliation(s)
- Evan Mann
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Olga G Ovchinnikova
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jerry D King
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Chris Whitfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Genomic Variability of Serial Human Isolates of Salmonella enterica Serovar Typhimurium Associated with Prolonged Carriage. J Clin Microbiol 2015; 53:3507-14. [PMID: 26311853 DOI: 10.1128/jcm.01733-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/18/2015] [Indexed: 12/22/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is an important foodborne human pathogen that often causes self-limiting but severe gastroenteritis. Prolonged excretion of S. Typhimurium after the infection can lead to secondary transmissions. However, little is known about within-host genomic variation in bacteria associated with asymptomatic shedding. Genomes of 35 longitudinal isolates of S. Typhimurium recovered from 11 patients (children and adults) with culture-confirmed gastroenteritis were sequenced. There were three or four isolates obtained from each patient. Single nucleotide polymorphisms (SNPs) were analyzed in these isolates, which were recovered between 1 and 279 days after the initial diagnosis. Limited genomic variation (5 SNPs or fewer) was associated with short- and long-term carriage of S. Typhimurium. None of the isolates was shown to be due to reinfection. SNPs occurred randomly, and the majority of the SNPs were nonsynonymous. Two nonsense mutations were observed. A nonsense mutation in flhC rendered the isolate nonmotile, whereas the significance of a nonsense mutation in yihV is unknown. The estimated mutation rate is 1.49 × 10(-6) substitution per site per year. S. Typhimurium isolates excreted in stools following acute gastroenteritis in children and adults demonstrated limited genomic variability over time, regardless of the duration of carriage. These findings have important implications for the detection of possible transmission events suspected by public health genomic surveillance of S. Typhimurium infections.
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Onsare RS, Micoli F, Lanzilao L, Alfini R, Okoro CK, Muigai AW, Revathi G, Saul A, Kariuki S, MacLennan CA, Rondini S. Relationship between antibody susceptibility and lipopolysaccharide O-antigen characteristics of invasive and gastrointestinal nontyphoidal Salmonellae isolates from Kenya. PLoS Negl Trop Dis 2015; 9:e0003573. [PMID: 25739091 PMCID: PMC4352093 DOI: 10.1371/journal.pntd.0003573] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 01/28/2015] [Indexed: 01/01/2023] Open
Abstract
Background Nontyphoidal Salmonellae (NTS) cause a large burden of invasive and gastrointestinal disease among young children in sub-Saharan Africa. No vaccine is currently available. Previous reports indicate the importance of the O-antigen of Salmonella lipopolysaccharide for virulence and resistance to antibody-mediated killing. We hypothesised that isolates with more O-antigen have increased resistance to antibody-mediated killing and are more likely to be invasive than gastrointestinal. Methodology/Principal Findings We studied 192 NTS isolates (114 Typhimurium, 78 Enteritidis) from blood and stools, mostly from paediatric admissions in Kenya 2000–2011. Isolates were tested for susceptibility to antibody-mediated killing, using whole adult serum. O-antigen structural characteristics, including O-acetylation and glucosylation, were investigated. Overall, isolates were susceptible to antibody-mediated killing, but S. Enteritidis were less susceptible and expressed more O-antigen than Typhimurium (p<0.0001 for both comparisons). For S. Typhimurium, but not Enteritidis, O-antigen expression correlated with reduced sensitivity to killing (r = 0.29, 95% CI = 0.10-0.45, p = 0.002). Both serovars expressed O-antigen populations ranging 21–33 kDa average molecular weight. O-antigen from most Typhimurium were O-acetylated on rhamnose and abequose residues, while Enteritidis O-antigen had low or no O-acetylation. Both Typhimurium and Enteritidis O-antigen were approximately 20%–50% glucosylated. Amount of S. Typhimurium O-antigen and O-antigen glucosylation level were inversely related. There was no clear association between clinical presentation and antibody susceptibility, O-antigen level or other O-antigen features. Conclusion/Significance Kenyan S. Typhimurium and Enteritidis clinical isolates are susceptible to antibody-mediated killing, with degree of susceptibility varying with level of O-antigen for S. Typhimurium. This supports the development of an antibody-inducing vaccine against NTS for Africa. No clear differences were found in the phenotype of isolates from blood and stool, suggesting that the same isolates can cause invasive disease and gastroenteritis. Genome studies are required to understand whether invasive and gastrointestinal isolates differ at the genotypic level. Nontyphoidal Salmonellae (NTS) are an emerging major cause of invasive bacterial disease in African children aged less than 5 years and immunocompromised adults, with an estimated case fatality rate of 20–25%. NTS also cause diarrhoea, a killer of about 1.5 million young children annually, mainly in low- and middle-income countries. No vaccine against NTS is available, but improved understanding of the Salmonella bacteria that cause disease in Africa would help the development of new vaccines. The authors characterized a collection of 192 Kenyan NTS strains (114 S. Typhimurium and 78 S. Enteritidis) from blood and stool specimens. All strains could be killed to differing extents by antibodies present in the blood of healthy HIV-uninfected African adults, supporting the development of a vaccine that will induce protective antibodies when given to African children. Differences in killing by antibody were partly related to the amount of O-antigen on the bacterial surface. There were no clear distinction between stains causing invasive disease and diarrhoea, suggesting that the same strains may be capable of causing both forms of disease. Clarification of this will require genomic analysis.
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Affiliation(s)
- Robert S. Onsare
- Centre for Microbiology Research (CMR), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
- Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Francesca Micoli
- Novartis Vaccines Institute for Global Health (NVGH), Siena, Italy
| | - Luisa Lanzilao
- Novartis Vaccines Institute for Global Health (NVGH), Siena, Italy
| | - Renzo Alfini
- Novartis Vaccines Institute for Global Health (NVGH), Siena, Italy
| | - Chinyere K. Okoro
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Anne W. Muigai
- Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Gunturu Revathi
- Division of Microbiology, Department of Pathology, Aga Khan University Hospital, Nairobi, Kenya
| | - Allan Saul
- Novartis Vaccines Institute for Global Health (NVGH), Siena, Italy
| | - Samuel Kariuki
- Centre for Microbiology Research (CMR), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | | | - Simona Rondini
- Novartis Vaccines Institute for Global Health (NVGH), Siena, Italy
- * E-mail:
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Kintz E, Davies MR, Hammarlöf DL, Canals R, Hinton JCD, van der Woude MW. A BTP1 prophage gene present in invasive non-typhoidal Salmonella determines composition and length of the O-antigen of the lipopolysaccharide. Mol Microbiol 2015; 96:263-75. [PMID: 25586744 PMCID: PMC4413052 DOI: 10.1111/mmi.12933] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/12/2015] [Indexed: 12/20/2022]
Abstract
Salmonella Typhimurium isolate D23580 represents a recently identified ST313 lineage of invasive non-typhoidal Salmonellae (iNTS). One of the differences between this lineage and other non-iNTS S. Typhimurium isolates is the presence of prophage BTP1. This prophage encodes a gtrC gene, implicated in O-antigen modification. GtrCBTP1 is essential for maintaining O-antigen length in isolate D23580, since a gtrBTP1 mutant yields a short O-antigen. This phenotype can be complemented by gtrCBTP1 or very closely related gtrC genes. The short O-antigen of the gtrBTP1 mutant was also compensated by deletion of the BTP1 phage tailspike gene in the D23580 chromosome. This tailspike protein has a putative endorhamnosidase domain and thus may mediate O-antigen cleavage. Expression of the gtrCBTP1 gene is, in contrast to expression of many other gtr operons, not subject to phase variation and transcriptional analysis suggests that gtrC is produced under a variety of conditions. Additionally, GtrCBTP1 expression is necessary and sufficient to provide protection against BTP1 phage infection of an otherwise susceptible strain. These data are consistent with a model in which GtrCBTP1 mediates modification of the BTP1 phage O-antigen receptor in lysogenic D23580, and thereby prevents superinfection by itself and other phage that uses the same O-antigen co-receptor.
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Affiliation(s)
- Erica Kintz
- Centre for Immunology and Infection, Hull York Medical School and the Department of Biology, University of York, York, UK
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44
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Identification of novel factors involved in modulating motility of Salmonella enterica serotype typhimurium. PLoS One 2014. [PMID: 25369209 DOI: 10.1371/journal.pone.0111513.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica serotype Typhimurium can move through liquid using swimming motility, and across a surface by swarming motility. We generated a library of targeted deletion mutants in Salmonella Typhimurium strain ATCC14028, primarily in genes specific to Salmonella, that we have previously described. In the work presented here, we screened each individual mutant from this library for the ability to move away from the site of inoculation on swimming and swarming motility agar. Mutants in genes previously described as important for motility, such as flgF, motA, cheY are do not move away from the site of inoculation on plates in our screens, validating our approach. Mutants in 130 genes, not previously known to be involved in motility, had altered movement of at least one type, 9 mutants were severely impaired for both types of motility, while 33 mutants appeared defective on swimming motility plates but not swarming motility plates, and 49 mutants had reduced ability to move on swarming agar but not swimming agar. Finally, 39 mutants were determined to be hypermotile in at least one of the types of motility tested. Both mutants that appeared non-motile and hypermotile on plates were assayed for expression levels of FliC and FljB on the bacterial surface and many of them had altered levels of these proteins. The phenotypes we report are the first phenotypes ever assigned to 74 of these open reading frames, as they are annotated as 'hypothetical genes' in the Typhimurium genome.
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45
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Bogomolnaya LM, Aldrich L, Ragoza Y, Talamantes M, Andrews KD, McClelland M, Andrews-Polymenis HL. Identification of novel factors involved in modulating motility of Salmonella enterica serotype typhimurium. PLoS One 2014; 9:e111513. [PMID: 25369209 PMCID: PMC4219756 DOI: 10.1371/journal.pone.0111513] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 09/28/2014] [Indexed: 12/03/2022] Open
Abstract
Salmonella enterica serotype Typhimurium can move through liquid using swimming motility, and across a surface by swarming motility. We generated a library of targeted deletion mutants in Salmonella Typhimurium strain ATCC14028, primarily in genes specific to Salmonella, that we have previously described. In the work presented here, we screened each individual mutant from this library for the ability to move away from the site of inoculation on swimming and swarming motility agar. Mutants in genes previously described as important for motility, such as flgF, motA, cheY are do not move away from the site of inoculation on plates in our screens, validating our approach. Mutants in 130 genes, not previously known to be involved in motility, had altered movement of at least one type, 9 mutants were severely impaired for both types of motility, while 33 mutants appeared defective on swimming motility plates but not swarming motility plates, and 49 mutants had reduced ability to move on swarming agar but not swimming agar. Finally, 39 mutants were determined to be hypermotile in at least one of the types of motility tested. Both mutants that appeared non-motile and hypermotile on plates were assayed for expression levels of FliC and FljB on the bacterial surface and many of them had altered levels of these proteins. The phenotypes we report are the first phenotypes ever assigned to 74 of these open reading frames, as they are annotated as ‘hypothetical genes’ in the Typhimurium genome.
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Affiliation(s)
- Lydia M. Bogomolnaya
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Lindsay Aldrich
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
| | - Yuri Ragoza
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
| | - Marissa Talamantes
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
| | - Katharine D. Andrews
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California Irvine, Irvine, California, United States of America
| | - Helene L. Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Bryan, Texas, United States of America
- * E-mail:
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46
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O'Brien JP, Needham BD, Brown DB, Trent MS, Brodbelt JS. Top-Down Strategies for the Structural Elucidation of Intact Gram-negative Bacterial Endotoxins. Chem Sci 2014; 5:4291-4301. [PMID: 25386333 PMCID: PMC4224326 DOI: 10.1039/c4sc01034e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Re-modelling of lipopolysaccharides, which are the primary constituent of the outer cell membrane of Gram-negative bacteria, modulates pathogenesis and resistance to microbials. Reported herein is the characterization of intact Gram-negative bacterial lipooligosaccharides (LOS) via a new strategy utilizing online liquid chromatography (LC) coupled with ultraviolet photodissociation (UVPD) mass spectrometry. Compared to collision-based MS/MS methods, UVPD and UVPD/HCD promoted a greater array of cleavages within both the glycan and lipid moieties, including C-C, C-N, C-O cleavages in the acyl chains as well as glycosidic and cross-ring cleavages, thus providing the most far-reaching structural characterization of LOS. This LC-MS/MS strategy affords a robust analytical method to structurally characterize complex mixtures of bacterial endotoxins that maintains the integrity of the core oligosaccharide and lipid A domains of LOS, providing direct feedback about the cell envelope architectures and LOS modification strategies involved in resistance host innate immune defense.
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Affiliation(s)
- John P O'Brien
- Department of Chemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX, USA 78712
| | - Brittany D Needham
- The University of Texas at Austin, Department of Molecular Biosciences, 2506 Speedway A5000, Austin, TX, USA 78712
| | - Dusty B Brown
- The University of Texas at Austin, Department of Molecular Biosciences, 2506 Speedway A5000, Austin, TX, USA 78712
| | - M Stephen Trent
- The University of Texas at Austin, Department of Molecular Biosciences, 2506 Speedway A5000, Austin, TX, USA 78712
| | - Jennifer S Brodbelt
- Department of Chemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX, USA 78712
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Rodriguez-Rivera LD, Moreno Switt AI, Degoricija L, Fang R, Cummings CA, Furtado MR, Wiedmann M, den Bakker HC. Genomic characterization of Salmonella Cerro ST367, an emerging Salmonella subtype in cattle in the United States. BMC Genomics 2014; 15:427. [PMID: 24898914 PMCID: PMC4070546 DOI: 10.1186/1471-2164-15-427] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/21/2014] [Indexed: 11/20/2023] Open
Abstract
Background Within the last decade, Salmonella enterica subsp. enterica serovar Cerro (S. Cerro) has become one of the most common serovars isolated from cattle and dairy farm environments in the northeastern US. The fact that this serovar is commonly isolated from subclinically infected cattle and is rarely associated with human disease, despite its frequent isolation from cattle, has led to the hypothesis that this emerging serovar may be characterized by reduced virulence. We applied comparative and population genomic approaches to (i) characterize the evolution of this recently emerged serovar and to (ii) gain a better understanding of genomic features that could explain some of the unique epidemiological features associated with this serovar. Results In addition to generating a de novo draft genome for one Salmonella Cerro strain, we also generated whole genome sequence data for 26 additional S. Cerro isolates, including 16 from cattle operations in New York (NY) state, 2 from human clinical cases from NY in 2008, and 8 from diverse animal sources (7 from Washington state and 1 from Florida). All isolates sequenced in this study represent sequence type ST367. Population genomic analysis showed that isolates from the NY cattle operations form a well-supported clade within S. Cerro ST367 (designated here “NY bovine clade”), distinct from isolates from Washington state, Florida and the human clinical cases. A molecular clock analysis indicates that the most recent common ancestor of the NY bovine clade dates back to 1998, supporting the recent emergence of this clone. Comparative genomic analyses revealed several relevant genomic features of S. Cerro ST367, that may be responsible for reduced virulence of S. Cerro, including an insertion creating a premature stop codon in sopA. In addition, patterns of gene deletion in S. Cerro ST367 further support adaptation of this clone to a unique ecological or host related niche. Conclusions Our results indicate that the increase in prevalence of S. Cerro ST367 is caused by a highly clonal subpopulation and that S. Cerro ST367 is characterized by unique genomic deletions that may indicate adaptation to specific ecological niches and possibly reduced virulence in some hosts. Electronic supplementary material The online version of this article (doi: 10.1186/1471-2164-15-427) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | - Henk C den Bakker
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
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Micoli F, Ravenscroft N, Cescutti P, Stefanetti G, Londero S, Rondini S, Maclennan CA. Structural analysis of O-polysaccharide chains extracted from different Salmonella Typhimurium strains. Carbohydr Res 2013; 385:1-8. [PMID: 24384528 DOI: 10.1016/j.carres.2013.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022]
Abstract
Salmonella Typhimurium is the major cause of invasive nontyphoidal Salmonella disease in Africa, with high mortality among children and HIV-infected individuals. Currently, no vaccine is available for use in humans. Antibodies directed against the O-polysaccharide of the lipopolysaccharide molecule of Salmonella mediate bacterial killing and are protective, and conjugation of the O-polysaccharide to a carrier protein represents a possible strategy for vaccine development. Here we have purified the O-polysaccharide from six different strains of S. Typhimurium and fully characterized them using analytical methods including HPLC-SEC, HPAEC-PAD, GC, GC-MS, 1D and 2D NMR spectroscopy. All the O-polysaccharide samples showed a similar bimodal molecular mass distribution, but differed with respect to the amount and position of O-acetylation and glucosylation. For some strains, O-acetyl groups were found not only on C-2 of abequose (factor 5 specificity), but also on C-2 and C-3 of rhamnose; glucose was found to be linked 1→4 or 1→6 to galactose in different amounts according to the strain of origin. This structural variability could have an impact on the immunogenicity of corresponding glycoconjugate vaccines and different strains need to be evaluated in order to identify the appropriate source of O-polysaccharide to use for the development of a candidate conjugate vaccine with broad coverage against S. Typhimurium.
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Affiliation(s)
- Francesca Micoli
- Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy.
| | - Neil Ravenscroft
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Paola Cescutti
- Dipartimento di Scienze della Vita, Ed. C11, Università di Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Giuseppe Stefanetti
- Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy
| | - Silvia Londero
- Dipartimento di Scienze della Vita, Ed. C11, Università di Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Simona Rondini
- Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy
| | - Calman A Maclennan
- Novartis Vaccines Institute for Global Health, Via Fiorentina 1, I-53100 Siena, Italy; Medical Research Council Centre for Immune Regulation, Institute of Biomedical Research, School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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49
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Tsonos J, Vandenheuvel D, Briers Y, De Greve H, Hernalsteens JP, Lavigne R. Hurdles in bacteriophage therapy: deconstructing the parameters. Vet Microbiol 2013; 171:460-9. [PMID: 24315040 DOI: 10.1016/j.vetmic.2013.11.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 10/26/2022]
Abstract
Bacterial infections in animals impact our food production, leading to economic losses due to food rejection and the need for preventive and curative measures. Since the onset of the antibiotic era, the rise of antibiotic-resistant pathogens is causing scares in health care and food producing facilities worldwide. In the search of new therapeutics, re-evaluation of bacteriophage (phage) therapy, using naturally occurring bacterial viruses to tackle infections, is gaining interest. Many studies report about phage therapy success, showing the value and power of these natural viruses. Although phages carry some interesting traits and their basic biology is now well understood, this review argues that phage therapy has not revealed all of its secrets and many parameters remain understudied, making the outcome of phage therapy highly variable depending on the disease incidence. These difficulties include poorly understood mechanisms of phage penetration and distribution throughout the body, the variable expression and accessibility of phage receptors on the bacterial host in in vivo conditions and the unusual (non-linear) phage pharmacokinetics. These parameters are not easily measured in realistic in vivo settings, but are nevertheless important hurdles to overcome the high variability of phage therapy trials. This critical approach is in accordance with Goethe's statement; "Difficulties increase the nearer we get to the goal". However, since the importance of the goal itself also rises, both difficulties and goal justify the need for additional in depth research in this domain.
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Affiliation(s)
- Jessica Tsonos
- Viral Genetics Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Department Structural Biology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Dieter Vandenheuvel
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Yves Briers
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Henri De Greve
- Structural and Molecular Microbiology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Department Structural Biology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| | | | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
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The ABC-type efflux pump MacAB protects Salmonella enterica serovar typhimurium from oxidative stress. mBio 2013; 4:e00630-13. [PMID: 24169575 PMCID: PMC3809562 DOI: 10.1128/mbio.00630-13] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Multidrug efflux pumps are integral membrane proteins known to actively excrete antibiotics. The macrolide-specific pump MacAB, the only ABC-type drug efflux pump in Salmonella, has previously been linked to virulence in mice. The molecular mechanism of this link between macAB and infection is unclear. We demonstrate that macAB plays a role in the detoxification of reactive oxygen species (ROS), compounds that salmonellae are exposed to at various stages of infection. macAB is induced upon exposure to H2O2 and is critical for survival of Salmonella enterica serovar Typhimurium in the presence of peroxide. Furthermore, we determined that macAB is required for intracellular replication inside J774.A1 murine macrophages but is not required for survival in ROS-deficient J774.D9 macrophages. macAB mutants also had reduced survival in the intestine in the mouse colitis model, a model characterized by a strong neutrophilic intestinal infiltrate where bacteria may experience the cytotoxic actions of ROS. Using an Amplex red-coupled assay, macAB mutants appear to be unable to induce protection against exogenous H2O2in vitro, in contrast to the isogenic wild type. In mixed cultures, the presence of the wild-type organism, or media preconditioned by the growth of the wild-type organism, was sufficient to rescue the macAB mutant from peroxide-mediated killing. Our data indicate that the MacAB drug efflux pump has functions beyond resistance to antibiotics and plays a role in the protection of Salmonella against oxidative stress. Intriguingly, our data also suggest the presence of a soluble anti-H2O2 compound secreted by Salmonella cells through a MacAB-dependent mechanism. The ABC-type multidrug efflux pump MacAB is known to be required for Salmonella enterica serovar Typhimurium virulence after oral infection in mice, yet the function of this pump during infection is unknown. We show that this pump is necessary for colonization of niches in infected mice where salmonellae encounter oxidative stress during infection. MacAB is required for growth in cultured macrophages that produce reactive oxygen species (ROS) but is not needed in macrophages that do not generate ROS. In addition, we show that MacAB is required to resist peroxide-mediated killing in vitro and for the inactivation of peroxide in the media. Finally, wild-type organisms, or supernatant from wild-type organisms grown in the presence of peroxide, rescue the growth defect of macAB mutants in H2O2. MacAB appears to participate in the excretion of a compound that induces protection against ROS-mediated killing, revealing a new role for this multidrug efflux pump.
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