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Ramatla T, Khasapane NG, Mlangeni LN, Mokgokong P, Ramaili T, Ndou R, Nkhebenyane JS, Lekota K, Thekisoe O. Detection of Salmonella Pathogenicity Islands and Antimicrobial-Resistant Genes in Salmonella enterica Serovars Enteritidis and Typhimurium Isolated from Broiler Chickens. Antibiotics (Basel) 2024; 13:458. [PMID: 38786186 PMCID: PMC11117945 DOI: 10.3390/antibiotics13050458] [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: 04/16/2024] [Revised: 05/06/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
Rapid growth in commercial poultry production is one of the major sources of Salmonella infections that leads to human salmonellosis. The two main Salmonella enterica serovars associated with human salmonellosis are enteritidis and typhimurium. The aim of this study was to determine the prevalence of S. enterica serovars Enteritidis and S. Typhimurium as well as their Salmonella pathogenicity islands (SPI) and antibiotic resistance profiles in broiler chicken feces from slaughterhouses. A total of 480 fecal samples from broiler chickens that were grouped into 96 pooled samples were identified to have Salmonella spp. using the invA gene, whilst the Spy and sdfI genes were used to screen for the presence of S. Enteritidis and S. Typhimurium serovars, respectively, by polymerase chain reaction (PCR) assays. The isolates were also screened for the presence of Salmonella pathogenicity islands (SPIs) using PCR. The disc diffusion assay was performed to determine the antibiotic resistance profiles of the isolates. A total of 36 isolates were confirmed as Salmonella spp. through amplification of the invA gene. Out of 36 confirmed Salmonella spp. a total of 22 isolates were classified as S. Enteritidis (n = 8) and were S. Typhimurium (n = 14) serovars. All (n = 22) S. Enteritidis and S. Typhimurium isolates possessed the hilA (SPI-1), ssrB (SPI-2) and pagC (SPI-11) pathogenicity islands genes. Amongst these serovars, 50% of the isolates (n = 11/22) were resistant to tetracycline and nalidixic acid. Only 22% of the isolates, S. Typhimurium (13.6%) and S. Enteritidis (9.1%) demonstrated resistance against three or more antibiotic classes. The most detected antibiotic resistance genes were tet(K), mcr-1, sulI and strA with 13 (59.1%), 9 (40.9%), 9 (40.9%) and 7 (31.8%), respectively. The findings of this study revealed that S. Typhimurium is the most prevalent serotype detected in chicken feces. To reduce the risk to human health posed by salmonellosis, a stringent public health and food safety policy is required.
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Affiliation(s)
- Tsepo Ramatla
- Centre for Applied Food Safety and Biotechnology, Department of Life Sciences, Central University of Technology, 1 Park Road, Bloemfontein 9300, South Africa; (T.R.); (J.S.N.)
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
| | - Ntelekwane G. Khasapane
- Centre for Applied Food Safety and Biotechnology, Department of Life Sciences, Central University of Technology, 1 Park Road, Bloemfontein 9300, South Africa; (T.R.); (J.S.N.)
| | - Lungile N. Mlangeni
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
| | - Prudent Mokgokong
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
| | - Taole Ramaili
- Department of Animal Health, School of Agriculture, North-West University, Mmabatho 2735, South Africa;
| | - Rendani Ndou
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
| | - Jane S. Nkhebenyane
- Centre for Applied Food Safety and Biotechnology, Department of Life Sciences, Central University of Technology, 1 Park Road, Bloemfontein 9300, South Africa; (T.R.); (J.S.N.)
| | - Kgaugelo Lekota
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
| | - Oriel Thekisoe
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2531, South Africa; (L.N.M.); (P.M.); (R.N.); (K.L.); (O.T.)
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Liang Z, Lu J, Bao Y, Chen X, Yao H, Wu Z. Glycerol metabolic repressor GlpR contributes to Streptococcus suis oxidative stress resistance and virulence. Microbes Infect 2024:105307. [PMID: 38309574 DOI: 10.1016/j.micinf.2024.105307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 02/05/2024]
Abstract
Bacterial DeoR family transcription regulators regulate multiple physiological processes. Little is known about the function of DeoR family regulators in streptococci. Here, we identified a novel DeoR family regulator, GlpR, from Streptococcus suis, a pathogen causing severe diseases in pigs and humans. GlpR was involved in glycerol utilization and exhibited specific signature residues at positions 30-31 (KV) which are crucial for DNA binding. Deletion of glpR (ΔglpR) showed a significant increase in relative growth rate in glycerol medium compared to the wild-type (WT) and complementary strains (CΔglpR). Employing RNA-seq analysis, β-galactosidase activity analysis, and electrophoretic mobility shift assay, we discovered that GlpR directly represses the expression of glycerol metabolism-related genes pflB2, pflA1, and fsaA, encoding pyruvate formate-lyase and its activating enzyme, and fructose-6-phosphate aldolase, respectively. Compared to WT and CΔglpR, ΔglpR showed a reduced survival rate under oxidative stress and in murine macrophages and attenuated virulence in mice. GlpR probably enhances oxidative stress resistance and virulence in S. suis by functioning as a glycerol metabolic repressor decreasing energy consumption. These findings contribute to a better understanding of S. suis pathogenesis and enrich our knowledge of the biological functions of DeoR family regulators in streptococci.
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Affiliation(s)
- Zijing Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China
| | - Jiaxuan Lu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China
| | - Yinli Bao
- Engineering Research Center for the Prevention and Control of Animal Original Zoonosis, College of Life Science, Longyan University, Longyan 364012, China
| | - Xiang Chen
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou 225009, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210014, China; WOAH Reference Lab for Swine Streptococcosis, Nanjing 210014, China; Guangdong Provincial Key Laboratory of Research on the Technology of Pig-breeding and Pig-disease Prevention, Guangzhou 511400, China.
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Lopez Chiloeches M, Bergonzini A, Martin OCB, Bergstein N, Erttmann SF, Aung KM, Gekara NO, Avila Cariño JF, Pateras IS, Frisan T. Genotoxin-producing Salmonella enterica induces tissue-specific types of DNA damage and DNA damage response outcomes. Front Immunol 2024; 14:1270449. [PMID: 38274797 PMCID: PMC10808668 DOI: 10.3389/fimmu.2023.1270449] [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: 07/31/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024] Open
Abstract
Introduction Typhoid toxin-expressing Salmonella enterica causes DNA damage in the intestinal mucosa in vivo, activating the DNA damage response (DDR) in the absence of inflammation. To understand whether the tissue microenvironment constrains the infection outcome, we compared the immune response and DDR patterns in the colon and liver of mice infected with a genotoxigenic strain or its isogenic control strain. Methods In situ spatial transcriptomic and immunofluorescence have been used to assess DNA damage makers, activation of the DDR, innate immunity markers in a multiparametric analysis. Result The presence of the typhoid toxin protected from colonic bacteria-induced inflammation, despite nuclear localization of p53, enhanced co-expression of type-I interferons (IfnbI) and the inflammasome sensor Aim2, both classic features of DNA-break-induced DDR activation. These effects were not observed in the livers of either infected group. Instead, in this tissue, the inflammatory response and DDR were associated with high oxidative stress-induced DNA damage. Conclusions Our work highlights the relevance of the tissue microenvironment in enabling the typhoid toxin to suppress the host inflammatory response in vivo.
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Affiliation(s)
- Maria Lopez Chiloeches
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
| | - Anna Bergonzini
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
| | - Océane C. B. Martin
- Biological and Medical Sciences Department, University Bordeaux, Centre National de la Recherche Scientifique (CNRS), Institut de Biochimie et Génétique Cellulaires (IBGC), Unité Mixte de Recherche (UMR) 5095, Bordeaux, France
| | - Nicole Bergstein
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
| | - Saskia F. Erttmann
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
- Infection Oncology Unit, Institute of Clinical Molecular Biology, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Kyaw Min Aung
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Nelson O. Gekara
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Institute of Medical Microbiology and Hygiene, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Javier F. Avila Cariño
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
| | - Ioannis S. Pateras
- Second Department of Pathology, “Attikon” University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Teresa Frisan
- Department of Molecular Biology and Umeå Centre for Microbial Research (UCMR) Umeå University, Umeå, Sweden
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The Salmonella T3SS1 effector IpaJ is regulated by ItrA and inhibits the MAPK signaling pathway. PLoS Pathog 2022; 18:e1011005. [PMID: 36477497 PMCID: PMC9728880 DOI: 10.1371/journal.ppat.1011005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
Invasion plasmid antigen J (IpaJ) is a protein with cysteine protease activity that is present in Salmonella and Shigella species. Salmonella enterica serovar Pullorum uses IpaJ to inhibit the NF-κB pathway and the subsequent inflammatory response, resulting in bacterial survival in host macrophages. In the present study, we performed a DNA pull-down assay and EMSA and identified ItrA, a new DeoR family transcriptional regulator that could control the expression of IpaJ by directly binding to the promoter of ipaJ. The deletion of itrA inhibited the transcription of ipaJ in Salmonella. Tn-Seq revealed that two regulators of Salmonella pathogenicity island 1 (SPI-1), namely HilA and HilD, regulated the secretion of IpaJ. The deletion of hilA, hilD or SPI-1 inhibited the secretion of IpaJ in both cultured medium and Salmonella-infected cells. In contrast, the strain with the deletion of ssrB (an SPI-2 regulator-encoding gene) displayed normal IpaJ secretion, indicating that IpaJ is an effector of the SPI-1-encoded type III secretion system (T3SS1). To further demonstrate the role of IpaJ in host cells, we performed quantitative phosphoproteomics and compared the fold changes in signaling molecules in HeLa cells infected with wild-type S. Pullorum C79-13 with those in HeLa cells infected with the ipaJ-deleted strain C79-13ΔpSPI12. Both phosphoproteomics and Western blot analyses revealed that p-MEK and p-ERK molecules were increased in C79-13ΔpSPI12- and C79-13ΔpSPI12-pipaJ(C45A)-infected cells; and Co-IP assays demonstrated that IpaJ interacts with Ras to reduce its ubiquitination, indicating that IpaJ can inhibit the activation of the MAPK signaling pathway.
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Shabbir MAB, Ul-Rahman A, Khalid AR, Ijaz N, Aleem MT, Ahmed S, Alouffi A, Ahmed W, Aslam F, Maan MK, Tahir AH, Aziz MW, Almutairi MM, Hao H. Inter-Relationship Between a Transcriptional Regulator of Flagella Genes cj0440c and Thiamine Metabolic Pathway in Campylobacter jejuni. BIOMED RESEARCH INTERNATIONAL 2022; 2022:4539367. [PMID: 36046445 PMCID: PMC9420602 DOI: 10.1155/2022/4539367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/20/2022] [Indexed: 12/03/2022]
Abstract
Campylobacter jejuni is a major cause of gastroenteritis in humans. It has been reported that the pathogenesis of C. jejuni is closely related to the formation, adhesion, and invasion of flagella toxin in host epithelial cells. A putative transcriptional regulator, known as cj0440c, is thought to be involved in the regulation of flagellar synthesis. However, confirmation of this hypothesis requires deep insight into the regulation mechanism of cj0440c and its possible relationship with different antibiotics. Therefore, the study explained here was designed to determine the relationship and function (phenotypically and genotypically) of cj0440c in the flagellar synthesis of C. jejuni NCTC11168. The study determined the mode of expression of cj0440c and flagella-related genes under exposure to various drugs. To verify the involvement of cj0440c protein in the metabolic pathway of thiamine, an enzymatic hydrolysis experiment was performed and analyzed through the application of mass spectrometry. The overexpression vector of C. jejuni NCTC11168 was also constructed to find out whether or not target genes were regulated by cj0440c. The findings of the study showed that cj0440c and other flagella-related genes were expressed differentially under the influence of various antibiotics including erythromycin, tylosin, azithromycin, gentamicin, etimicin, enrofloxacin, gatifloxacin, tetracycline, and tigecycline. The analysis showed that the cj0440c protein did not catalyze the degradation of thiamine. In conclusion, the study aids in the understanding of the inter-relationship between the regulatory mechanism of flagella genes and the thiamine metabolic pathway.
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Affiliation(s)
| | - Aziz Ul-Rahman
- Department of Pathobiology, Faculty of Veterinary and Animal Sciences, MNS University of Agriculture, Multan 66000, Pakistan
| | - Abdur Rauf Khalid
- Department of Livestock and Poultry Production, Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
| | - Nabeel Ijaz
- Department of Clinical Sciences, Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
| | - Muhammmad Tahir Aleem
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Saeed Ahmed
- Department of Biological Sciences, National University of Medical Sciences (NUMS), Islamabad, Pakistan
| | - Abdulaziz Alouffi
- King Abdulaziz City for Science and Technology, Riyadh 12354, Saudi Arabia
| | - Waqas Ahmed
- Department of Biomedical and Diagnostic Science, University of Tennessee Knoxville, USA
| | - Faiza Aslam
- Livestock and Dairy Development Department, Lahore 54000, Pakistan
| | - Muhammad Kashif Maan
- Department of Veterinary Surgery and Pet Sciences, Faculty of Veterinary Science, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Adnan Hassan Tahir
- Department of Clinical Sciences, Faculty of Veterinary and Animal Sciences, PMAS-Arid Agriculture University Rawalpindi, Pakistan
| | - Muhammad Waqar Aziz
- Institute of Microbiology, University of Veterinary and Animal Sciences Lahore, 54600, Pakistan
| | - Mashal M. Almutairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality & Safety of Livestock & Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
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Abstract
Salmonella enterica serovar Typhi ISP2825, isolated in 1983 from a Chilean patient, is one of the major S. Typhi strains used for research, along with strains Ty2, CT18, and H58. The complete genome sequence of ISP2825, consisting of a 4,774,014-bp circular chromosome, will help us understand typhoid pathogenesis and evolution.
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Matanza XM, Osorio CR. Transcriptome changes in response to temperature in the fish pathogen Photobacterium damselae subsp. damselae: Clues to understand the emergence of disease outbreaks at increased seawater temperatures. PLoS One 2018; 13:e0210118. [PMID: 30596794 PMCID: PMC6312309 DOI: 10.1371/journal.pone.0210118] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/17/2018] [Indexed: 01/22/2023] Open
Abstract
The marine bacterium Photobacterium damselae subsp. damselae (Pdd) is a generalist and facultative pathogen that causes disease in a wide range of marine animals including fish species of importance in aquaculture. Disease outbreaks in fish farms have been correlated with an increased water temperature during summer months. In this study, we have used RNA sequencing to analyze the transcriptome of Pdd RM-71 cultured at two different temperatures, which simulated temperature conditions experienced during free swimming lifestyle at mid latitudes in winter months (15°C) and during outbreaks in aquaculture in warm summer months (25°C). The enhanced bacterial growth of Pdd observed at 25°C in comparison to 15°C suggests that an elevated seawater temperature contributes to the build-up of a sufficient bacterial population to cause disease. In comparison to growth at 15°C, growth at 25°C resulted in the upregulation of genes involved in DNA synthesis, nutrient uptake, chemotaxis, flagellar motility, secretion systems and antimicrobial resistance. Plasmid-encoded virulence factors, which include a putative adhesin/invasin OmpU, a transferrin receptor and a serum resistance protein, were also upregulated. Transcription factor RpoS, genes involved in cold shock response, modulation of cell envelope and amino acid metabolism, as well as genes of yet unknown function were downregulated at 25°C. Notably, the gene encoding damselysin cytotoxin (Dly) was among the most highly transcribed genes at the two assayed temperatures, at levels comparable to the most highly expressed housekeeping genes. This study contributes to our understanding of the regulatory networks and biology of a generalist marine bacterial pathogen, and provides evidence that temperature regulates multiple physiological and virulence-related functions in Pdd.
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Affiliation(s)
- Xosé M. Matanza
- Departamento de Microbioloxía e Parasitoloxía, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Carlos R. Osorio
- Departamento de Microbioloxía e Parasitoloxía, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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Fowler CC, Galán JE. Decoding a Salmonella Typhi Regulatory Network that Controls Typhoid Toxin Expression within Human Cells. Cell Host Microbe 2018; 23:65-76.e6. [PMID: 29324231 DOI: 10.1016/j.chom.2017.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/26/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
Salmonella Typhi is the cause of typhoid fever, a major global health concern. An essential virulence factor of this pathogen is typhoid toxin. In contrast to most AB-type toxins, typhoid toxin is exclusively expressed by intracellular bacteria. The regulatory networks that ensure this unique gene expression pattern are unknown. Here, we developed FAST-INSeq, a genome-wide screening approach to identify S. Typhi genes required for typhoid toxin expression within infected cells. We find that typhoid toxin expression is controlled by a silencing and counter-silencing mechanism through the opposing actions of the PhoP/PhoQ two-component regulatory system and the histone-like protein H-NS. The screen also identified bacterial mutants that alter the proportion of intracellular S. Typhi that reside within an intravacuolar environment, which was essential for toxin expression. Collectively, these data describe a regulatory mechanism that allows a bacterial pathogen to exclusively express a virulence factor when located within a specific intracellular compartment.
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Affiliation(s)
- Casey C Fowler
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Jorge E Galán
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA.
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9
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Comparative study of Salmonella enterica serovar Enteritidis genes expressed within avian and murine macrophages via selective capture of transcribed sequences (SCOTS). Appl Microbiol Biotechnol 2018; 102:6567-6579. [PMID: 29799087 DOI: 10.1007/s00253-018-9067-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 04/26/2018] [Accepted: 05/01/2018] [Indexed: 10/16/2022]
Abstract
Salmonella enterica serovar Enteritidis (SE) is a communicable zoonotic bacterium. Macrophages are essential for Salmonella survival, transmission, and infection. In this study, selective capture of transcribed sequences (SCOTS) was used to screen genes preferentially expressed by SE during contact with macrophages from different hosts. We found 57 predicted genes and 52 genes expressed by SE during interaction with avian HD-11 and murine RAW264.7 cells, respectively. These expressed genes were involved in virulence, metabolism, stress response, transport, regulation, and other functions. Although genes related to survival or metabolic pathways were needed during SE infection, different gene expression profiles of SE occurred in the two macrophage cell lines. qRT-PCR results confirmed that most screened genes were upregulated during infection in contrast to the observation during in vitro cultivation, with different expression levels in infected avian macrophages at 2-h and 7-h post-infection. In addition, in vitro and in vivo competition assays confirmed that SEN3610 (a putative deoR family regulator) and rfaQ (related to LPS synthesis) were closely related to SE virulence in both mice and chickens. Three putative transcriptional regulators, SEN2967, SEN4299, and rtcR, were related to SE colonization in mice, while the ycaM mutation caused decreased infection and survival of SE in HD-11 cells without influencing virulence in mice or chicken. Genes showing differential expression between SE-infected avian and murine macrophages indicate specific pathogen adaptation to enable infection of various hosts.
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10
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Hao H, Fang X, Han J, Foley SL, Wang Y, Cheng G, Wang X, Huang L, Dai M, Liu Z, Yuan Z. Cj0440c Affects Flagella Formation and In Vivo Colonization of Erythromycin-Susceptible and -Resistant Campylobacter jejuni. Front Microbiol 2017; 8:729. [PMID: 28487689 PMCID: PMC5403827 DOI: 10.3389/fmicb.2017.00729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 04/07/2017] [Indexed: 12/11/2022] Open
Abstract
Campylobacter jejuni is one of the most common foodborne pathogen worldwide. A putative transcriptional regulator, Cj0440c, was up-regulated in the erythromycin-resistant C. jejuni, however, the precise role of Cj0440c is yet to be determined. The aim of this study was to determine the biological functions of Cj0440c. The Cj0440c isogenic mutants were constructed from erythromycin-susceptible C. jejuni NCTC 11168 (S) and -resistant C. jejuni 68-ER (R), designating as SM and RM, respectively. The isogenic Cj0440c mutants (SM and RM) and parental strains (S and R) were subjected to microarray and qRT-PCR analysis to examine the transcriptional profile changes contributed by Cj0440c. The antimicrobial susceptibility, flagellar morphology, in vitro growth and in vivo colonization in chickens were carried out to analyze the biological function of Cj0440c. The results showed that 17 genes were down-regulated in SM compared to S, while 9 genes were down-regulated in RM compared to R. The genes with transcriptional change were mainly involved in flagella biosynthesis and assembly. Using transmission electron microscopy, we found that the filaments were impaired in SM and lost in RM. The chicken colonization experiments showed that Cj0440c mutants (SM and RM) had reduced colonization ability in chickens when compared with corresponding parental strains (S and R). In conclusion, Cj0440c regulates flagella biosynthesis and assembly, and consequently affect the in vivo colonization of erythromycin-susceptible and -resistant C. jejuni.
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Affiliation(s)
- Haihong Hao
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Xia Fang
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Jing Han
- Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, JeffersonAR, USA
| | - Steven L Foley
- Division of Microbiology, National Center for Toxicological Research, US Food and Drug Administration, JeffersonAR, USA
| | - Yulian Wang
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Guyue Cheng
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Lingli Huang
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Menghong Dai
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Zhenli Liu
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
| | - Zonghui Yuan
- National Reference Laboratory of Veterinary Drug Residues and MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China.,MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China
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Miller R, Wiedmann M. Dynamic Duo-The Salmonella Cytolethal Distending Toxin Combines ADP-Ribosyltransferase and Nuclease Activities in a Novel Form of the Cytolethal Distending Toxin. Toxins (Basel) 2016; 8:E121. [PMID: 27120620 PMCID: PMC4885037 DOI: 10.3390/toxins8050121] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/30/2016] [Accepted: 04/15/2016] [Indexed: 01/02/2023] Open
Abstract
The cytolethal distending toxin (CDT) is a well characterized bacterial genotoxin encoded by several Gram-negative bacteria, including Salmonella enterica (S. enterica). The CDT produced by Salmonella (S-CDT) differs from the CDT produced by other bacteria, as it utilizes subunits with homology to the pertussis and subtilase toxins, in place of the traditional CdtA and CdtC subunits. Previously, S-CDT was thought to be a unique virulence factor of S. enterica subspecies enterica serotype Typhi, lending to its classification as the "typhoid toxin." Recently, this important virulence factor has been identified and characterized in multiple nontyphoidal Salmonella (NTS) serotypes as well. The significance of S-CDT in salmonellosis with regards to the: (i) distribution of S-CDT encoding genes among NTS serotypes, (ii) contributions to pathogenicity, (iii) regulation of S-CDT expression, and (iv) the public health implication of S-CDT as it relates to disease severity, are reviewed here.
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Affiliation(s)
- Rachel Miller
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
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Characterization of intracellular growth regulator icgR by utilizing transcriptomics to identify mediators of pathogenesis in Shigella flexneri. Infect Immun 2013; 81:3068-76. [PMID: 23753632 DOI: 10.1128/iai.00537-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigella species Gram-negative bacteria which cause a diarrheal disease, known as shigellosis, by invading and destroying the colonic mucosa and inducing a robust inflammatory response. With no vaccine available, shigellosis annually kills over 600,000 children in developing countries. This study demonstrates the utility of combining high-throughput bioinformatic methods with in vitro and in vivo assays to provide new insights into pathogenesis. Comparisons of in vivo and in vitro gene expression identified genes associated with intracellular growth. Additional bioinformatics analyses identified genes that are present in S. flexneri isolates but not in the three other Shigella species. Comparison of these two analyses revealed nine genes that are differentially expressed during invasion and that are specific to S. flexneri. One gene, a DeoR family transcriptional regulator with decreased expression during invasion, was further characterized and is now designated icgR, for intracellular growth regulator. Deletion of icgR caused no difference in growth in vitro but resulted in increased intracellular replication in HCT-8 cells. Further in vitro and in vivo studies using high-throughput sequencing of RNA transcripts (RNA-seq) of an isogenic ΔicgR mutant identified 34 genes that were upregulated under both growth conditions. This combined informatics and functional approach has allowed the characterization of a gene and pathway previously unknown in Shigella pathogenesis and provides a framework for further identification of novel virulence factors and regulatory pathways.
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13
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Drennan SL, Lama A, Doron B, Cambronne ED. Tractable mammalian cell infections with protozoan-primed bacteria. J Vis Exp 2013. [PMID: 23609210 DOI: 10.3791/50300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Many intracellular bacterial pathogens use freshwater protozoans as a natural reservoir for proliferation in the environment. Legionella pneumophila, the causative agent of Legionnaires' pneumonia, gains a pathogenic advantage over in vitro cultured bacteria when first harvested from protozoan cells prior to infection of mammalian macrophages. This suggests that important virulence factors may not be properly expressed in vitro. We have developed a tractable system for priming L. pneumophila through its natural protozoan host Acanthamoeba castellanii prior to mammalian cell infection. The contribution of any virulence factor can be examined by comparing intracellular growth of a mutant strain to wild-type bacteria after protozoan priming. GFP-expressing wild-type and mutant L. pneumophila strains are used to infect protozoan monolayers in a priming step and allowed to reach late stages of intracellular growth. Fluorescent bacteria are then harvested from these infected cells and normalized by spectrophotometry to generate comparable numbers of bacteria for a subsequent infection into mammalian macrophages. For quantification, live bacteria are monitored after infection using fluorescence microscopy, flow cytometry, and by colony plating. This technique highlights and relies on the contribution of host cell-dependent gene expression by mimicking the environment that would be encountered in a natural acquisition route. This approach can be modified to accommodate any bacterium that uses an intermediary host as a means for gaining a pathogenic advantage.
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Affiliation(s)
- Samuel L Drennan
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, USA
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14
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A Salmonella Typhi homologue of bacteriophage muramidases controls typhoid toxin secretion. EMBO Rep 2012; 14:95-102. [PMID: 23174673 DOI: 10.1038/embor.2012.186] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/15/2012] [Accepted: 10/25/2012] [Indexed: 11/09/2022] Open
Abstract
Unlike other Salmonella, which can infect a broad range of hosts causing self-limiting infection, Salmonella Typhi is an exclusively human pathogen that causes typhoid fever, a life-threatening systemic disease. Typhoid toxin is a unique virulence factor of Salmonella Typhi, which is expressed when the bacteria are within mammalian cells. Here, we report that an N-acetyl-β-D-muramidase similar to phage endolysins encoded within the same pathogenicity islet as the toxin is required for typhoid toxin secretion. Genetic and functional analysis of TtsA revealed unique amino acids at its predicted peptidoglycan-binding domain that are essential for protein secretion and that distinguishes this protein from other homologues. We propose that TtsA defines a new protein secretion mechanism recently evolved from the machine that mediates phage release.
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15
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Kim KM, Kim KW, Sung S, Kim H. A genome-wide identification of genes potentially associated with host specificity of Brucella species. J Microbiol 2011; 49:768-75. [DOI: 10.1007/s12275-011-1084-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 05/20/2011] [Indexed: 11/30/2022]
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16
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McBride SM, Sonenshein AL. The dlt operon confers resistance to cationic antimicrobial peptides in Clostridium difficile. MICROBIOLOGY-SGM 2011; 157:1457-1465. [PMID: 21330441 DOI: 10.1099/mic.0.045997-0] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The dlt operon in Gram-positive bacteria encodes proteins that are necessary for the addition of d-alanine to teichoic acids of the cell wall. The addition of d-alanine to the cell wall results in a net positive charge on the bacterial cell surface and, as a consequence, can decrease the effectiveness of antimicrobials, such as cationic antimicrobial peptides (CAMPs). Although the roles of the dlt genes have been studied for some Gram-positive organisms, the arrangement of these genes in Clostridium difficile and the life cycle of the bacterium in the host are markedly different from those of other pathogens. In the current work, we determined the contribution of the putative C. difficile dlt operon to CAMP resistance. Our data indicate that the dlt operon is necessary for full resistance of C. difficile to nisin, gallidermin, polymyxin B and vancomycin. We propose that the d-alanylation of teichoic acids provides protection against antimicrobial peptides that may be essential for growth of C. difficile in the host.
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Affiliation(s)
- Shonna M McBride
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Abraham L Sonenshein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
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17
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GlpR represses fructose and glucose metabolic enzymes at the level of transcription in the haloarchaeon Haloferax volcanii. J Bacteriol 2010; 192:6251-60. [PMID: 20935102 DOI: 10.1128/jb.00827-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, a DeoR/GlpR-type transcription factor was investigated for its potential role as a global regulator of sugar metabolism in haloarchaea, using Haloferax volcanii as a model organism. Common to a number of haloarchaea and Gram-positive bacterial species, the encoding glpR gene was chromosomally linked with genes of sugar metabolism. In H. volcanii, glpR was cotranscribed with the downstream phosphofructokinase (PFK; pfkB) gene, and the transcript levels of this glpR-pfkB operon were 10- to 20-fold higher when cells were grown on fructose or glucose than when they were grown on glycerol alone. GlpR was required for repression on glycerol based on significant increases in the levels of PFK (pfkB) transcript and enzyme activity detected upon deletion of glpR from the genome. Deletion of glpR also resulted in significant increases in both the activity and the transcript (kdgK1) levels of 2-keto-3-deoxy-D-gluconate kinase (KDGK), a key enzyme of haloarchaeal glucose metabolism, when cells were grown on glycerol, compared to the levels obtained for media with glucose. Promoter fusions to a β-galactosidase bgaH reporter revealed that transcription of glpR-pfkB and kdgK1 was modulated by carbon source and GlpR, consistent with quantitative reverse transcription-PCR (qRT-PCR) and enzyme activity assays. The results presented here provide genetic and biochemical evidence that GlpR controls both fructose and glucose metabolic enzymes through transcriptional repression of the glpR-pfkB operon and kdgK1 during growth on glycerol.
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Weeks JN, Galindo CL, Drake KL, Adams GL, Garner HR, Ficht TA. Brucella melitensis VjbR and C12-HSL regulons: contributions of the N-dodecanoyl homoserine lactone signaling molecule and LuxR homologue VjbR to gene expression. BMC Microbiol 2010; 10:167. [PMID: 20529360 PMCID: PMC2898763 DOI: 10.1186/1471-2180-10-167] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 06/08/2010] [Indexed: 12/25/2022] Open
Abstract
Background Quorum sensing is a communication system that regulates gene expression in response to population density and often regulates virulence determinants. Deletion of the luxR homologue vjbR highly attenuates intracellular survival of Brucella melitensis and has been interpreted to be an indication of a role for QS in Brucella infection. Confirmation for such a role was suggested, but not confirmed, by the demonstrated in vitro synthesis of an auto-inducer (AI) by Brucella cultures. In an effort to further delineate the role of VjbR to virulence and survival, gene expression under the control of VjbR and AI was characterized using microarray analysis. Results Analyses of wildtype B. melitensis and isogenic ΔvjbR transciptomes, grown in the presence and absence of exogenous N-dodecanoyl homoserine lactone (C12-HSL), revealed a temporal pattern of gene regulation with variances detected at exponential and stationary growth phases. Comparison of VjbR and C12-HSL transcriptomes indicated the shared regulation of 127 genes with all but 3 genes inversely regulated, suggesting that C12-HSL functions via VjbR in this case to reverse gene expression at these loci. Additional analysis using a ΔvjbR mutant revealed that AHL also altered gene expression in the absence of VjbR, up-regulating expression of 48 genes and a luxR homologue blxR 93-fold at stationary growth phase. Gene expression alterations include previously un-described adhesins, proteases, antibiotic and toxin resistance genes, stress survival aids, transporters, membrane biogenesis genes, amino acid metabolism and transport, transcriptional regulators, energy production genes, and the previously reported fliF and virB operons. Conclusions VjbR and C12-HSL regulate expression of a large and diverse number of genes. Many genes identified as virulence factors in other bacterial pathogens were found to be differently expressed, suggesting an important contribution to intracellular survival of Brucella. From these data, we conclude that VjbR and C12-HSL contribute to virulence and survival by regulating expression of virulence mechanisms and thus controlling the ability of the bacteria to survive within the host cell. A likely scenario occurs via QS, however, operation of such a mechanism remains to be demonstrated.
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Affiliation(s)
- Jenni N Weeks
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A & M University, College Station, TX 77843-4467, USA.
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Charles RC, Harris JB, Chase MR, Lebrun LM, Sheikh A, LaRocque RC, Logvinenko T, Rollins SM, Tarique A, Hohmann EL, Rosenberg I, Krastins B, Sarracino DA, Qadri F, Calderwood SB, Ryan ET. Comparative proteomic analysis of the PhoP regulon in Salmonella enterica serovar Typhi versus Typhimurium. PLoS One 2009; 4:e6994. [PMID: 19746165 PMCID: PMC2736619 DOI: 10.1371/journal.pone.0006994] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 07/24/2009] [Indexed: 12/20/2022] Open
Abstract
Background S. Typhi, a human-restricted Salmonella
enterica serovar, causes a systemic intracellular infection in
humans (typhoid fever). In comparison, S. Typhimurium
causes gastroenteritis in humans, but causes a systemic typhoidal illness in
mice. The PhoP regulon is a well studied two component (PhoP/Q) coordinately
regulated network of genes whose expression is required for intracellular
survival of S. enterica. Methodology/Principal Findings Using high performance liquid chromatography mass spectrometry (HPLC-MS/MS),
we examined the protein expression profiles of three sequenced S.
enterica strains: S. Typhimurium LT2,
S. Typhi CT18, and S. Typhi Ty2 in
PhoP-inducing and non-inducing conditions in vitro and
compared these results to profiles of
phoP−/Q−
mutants derived from S. Typhimurium LT2 and
S. Typhi Ty2. Our analysis identified 53 proteins in
S. Typhimurium LT2 and 56 proteins in
S. Typhi that were regulated in a PhoP-dependent manner. As
expected, many proteins identified in S. Typhi demonstrated
concordant differential expression with a homologous protein in
S. Typhimurium. However, three proteins (HlyE, STY1499, and
CdtB) had no homolog in S. Typhimurium. HlyE is a
pore-forming toxin. STY1499 encodes a stably expressed protein of unknown
function transcribed in the same operon as HlyE. CdtB is a cytolethal
distending toxin associated with DNA damage, cell cycle arrest, and cellular
distension. Gene expression studies confirmed up-regulation of mRNA of HlyE,
STY1499, and CdtB in S. Typhi in PhoP-inducing
conditions. Conclusions/Significance This study is the first protein expression study of the PhoP virulence
associated regulon using strains of Salmonella mutant in
PhoP, has identified three Typhi-unique proteins (CdtB, HlyE and STY1499)
that are not present in the genome of the wide host-range Typhimurium, and
includes the first protein expression profiling of a live attenuated
bacterial vaccine studied in humans (Ty800).
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Affiliation(s)
- Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
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20
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Jandu N, Ho NKL, Donato KA, Karmali MA, Mascarenhas M, Duffy SP, Tailor C, Sherman PM. Enterohemorrhagic Escherichia coli O157:H7 gene expression profiling in response to growth in the presence of host epithelia. PLoS One 2009; 4:e4889. [PMID: 19293938 PMCID: PMC2654852 DOI: 10.1371/journal.pone.0004889] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 02/04/2009] [Indexed: 12/30/2022] Open
Abstract
Background The pathogenesis of enterohemorrhagic Escherichia coli (EHEC) O157∶H7 infection is attributed to virulence factors encoded on multiple pathogenicity islands. Previous studies have shown that EHEC O157∶H7 modulates host cell signal transduction cascades, independent of toxins and rearrangement of the cytoskeleton. However, the virulence factors and mechanisms responsible for EHEC-mediated subversion of signal transduction remain to be determined. Therefore, the purpose of this study was to first identify differentially regulated genes in response to EHEC O157∶H7 grown in the presence of epithelial cells, compared to growth in the absence of epithelial cells (that is, growth in minimal essential tissue culture medium alone, minimal essential tissue culture medium in the presence of 5% CO2, and Penassay broth alone) and, second, to identify EHEC virulence factors responsible for pathogen modulation of host cell signal transduction. Methodology/Principal Findings Overnight cultures of EHEC O157∶H7 were incubated for 6 hr at 37°C in the presence or absence of confluent epithelial (HEp-2) cells. Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips). Relative to bacteria grown in each of the other conditions, EHEC O157∶H7 cultured in the presence of cultured epithelial cells displayed a distinct gene-expression profile. A 2.0-fold increase in the expression of 71 genes and a 2.0-fold decrease in expression of 60 other genes were identified in EHEC O157∶H7 grown in the presence of epithelial cells, compared to bacteria grown in media alone. Conclusion/Significance Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-γ-Jak1,2-STAT-1 signal transduction cascade. Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process.
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Affiliation(s)
- Narveen Jandu
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States of America
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Nathan K. L. Ho
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Kevin A. Donato
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Mohamed A. Karmali
- Laboratory of Foodborne Zoonosis, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Mariola Mascarenhas
- Laboratory of Foodborne Zoonosis, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Simon P. Duffy
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Chetankumar Tailor
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Philip M. Sherman
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Yoon H, McDermott JE, Porwollik S, McClelland M, Heffron F. Coordinated regulation of virulence during systemic infection of Salmonella enterica serovar Typhimurium. PLoS Pathog 2009; 5:e1000306. [PMID: 19229334 PMCID: PMC2639726 DOI: 10.1371/journal.ppat.1000306] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 01/22/2009] [Indexed: 11/18/2022] Open
Abstract
To cause a systemic infection, Salmonella must respond to many environmental cues during mouse infection and express specific subsets of genes in a temporal and spatial manner, but the regulatory pathways are poorly established. To unravel how micro-environmental signals are processed and integrated into coordinated action, we constructed in-frame non-polar deletions of 83 regulators inferred to play a role in Salmonella enteriditis Typhimurium (STM) virulence and tested them in three virulence assays (intraperitoneal [i.p.], and intragastric [i.g.] infection in BALB/c mice, and persistence in 129X1/SvJ mice). Overall, 35 regulators were identified whose absence attenuated virulence in at least one assay, and of those, 14 regulators were required for systemic mouse infection, the most stringent virulence assay. As a first step towards understanding the interplay between a pathogen and its host from a systems biology standpoint, we focused on these 14 genes. Transcriptional profiles were obtained for deletions of each of these 14 regulators grown under four different environmental conditions. These results, as well as publicly available transcriptional profiles, were analyzed using both network inference and cluster analysis algorithms. The analysis predicts a regulatory network in which all 14 regulators control the same set of genes necessary for Salmonella to cause systemic infection. We tested the regulatory model by expressing a subset of the regulators in trans and monitoring transcription of 7 known virulence factors located within Salmonella pathogenicity island 2 (SPI-2). These experiments validated the regulatory model and showed that the response regulator SsrB and the MarR type regulator, SlyA, are the terminal regulators in a cascade that integrates multiple signals. Furthermore, experiments to demonstrate epistatic relationships showed that SsrB can replace SlyA and, in some cases, SlyA can replace SsrB for expression of SPI-2 encoded virulence factors.
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Affiliation(s)
- Hyunjin Yoon
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jason E. McDermott
- Pacific Northwest National Laboratories, Richland, Washington, United States of America
| | - Steffen Porwollik
- The Sydney Kimmel Cancer Center, San Diego, California, United States of America
| | - Michael McClelland
- The Sydney Kimmel Cancer Center, San Diego, California, United States of America
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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Ansong C, Yoon H, Norbeck AD, Gustin JK, McDermott JE, Mottaz HM, Rue J, Adkins JN, Heffron F, Smith RD. Proteomics analysis of the causative agent of typhoid fever. J Proteome Res 2008; 7:546-57. [PMID: 18166006 DOI: 10.1021/pr070434u] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Typhoid fever is a potentially fatal disease caused by the bacterial pathogen Salmonella enterica serotype Typhi ( S. typhi). S. typhi infection is a complex process that involves numerous bacterially encoded virulence determinants, and these are thought to confer both stringent human host specificity and a high mortality rate. In the present study, we used a liquid chromatography-mass spectrometry (LC-MS)-based proteomics strategy to investigate the proteome of logarithmic, stationary phase, and low pH/low magnesium (MgM) S. typhi cultures. This represents the first large-scale comprehensive characterization of the S. typhi proteome. Our analysis identified a total of 2066 S. typhi proteins. In an effort to identify putative S. typhi-specific virulence factors, we then compared our S. typhi results to those obtained in a previously published study of the S. typhimurium proteome under similar conditions ( Adkins, J. N. et al. Mol. Cell. Proteomics 2006, 5, 1450-1461 ). Comparative proteomics analysis of S. typhi strain Ty2 and S. typhimurium strain LT2 revealed a subset of highly expressed proteins unique to S. typhi that were exclusively detected under conditions that are thought to mimic the infective state in macrophage cells. These proteins included CdtB, HlyE, and gene products of t0142, t1108, t1109, t1476, and t1602. The differential expression of T1108, T1476, and HlyE was confirmed by Western blot analysis. When our observations are taken together with the current literature, they suggest that this subset of proteins may play a role in S. typhi pathogenesis and human host specificity.
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Affiliation(s)
- Charles Ansong
- Biological Sciences Division, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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