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Tang X, Xu S, Yang Z, Wang K, Dai K, Zhang Y, Hu B, Wang Y, Cao S, Huang X, Yan Q, Wu R, Zhao Q, Du S, Wen X, Wen Y. EspP2 Regulates the Adhesion of Glaesserella parasuis via Rap1 Signaling Pathway. Int J Mol Sci 2024; 25:4570. [PMID: 38674155 PMCID: PMC11050538 DOI: 10.3390/ijms25084570] [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: 02/29/2024] [Revised: 04/07/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
Different levels of EspP2 expression are seen in strains of Glaesserella parasuis with high and low pathogenicity. As a potential virulence factor for G. parasuis, the pathogenic mechanism of EspP2 in infection of host cells is not clear. To begin to elucidate the effect of EspP2 on virulence, we used G. parasuis SC1401 in its wild-type form and SC1401, which was made EspP2-deficient. We demonstrated that EspP2 causes up-regulation of claudin-1 and occludin expression, thereby promoting the adhesion of G. parasuis to host cells; EspP2-deficiency resulted in significantly reduced adhesion of G. parasuis to cells. Transcriptome sequencing analysis of EspP2-treated PK15 cells revealed that the Rap1 signaling pathway is stimulated by EspP2. Blocking this pathway diminished occludin expression and adhesion. These results indicated that EspP2 regulates the adhesion of Glaesserella parasuis via Rap1 signaling pathway.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Yiping Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
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2
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Stromberg ZR, Phillips SMB, Omberg KM, Hess BM. High-throughput functional trait testing for bacterial pathogens. mSphere 2023; 8:e0031523. [PMID: 37702517 PMCID: PMC10597404 DOI: 10.1128/msphere.00315-23] [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] [Indexed: 09/14/2023] Open
Abstract
Functional traits are characteristics that affect the fitness and metabolic function of a microorganism. There is growing interest in using high-throughput methods to characterize bacterial pathogens based on functional virulence traits. Traditional methods that phenotype a single organism for a single virulence trait can be time consuming and labor intensive. Alternatively, machine learning of whole-genome sequences (WGS) has shown some success in predicting virulence. However, relying solely on WGS can miss functional traits, particularly for organisms lacking classical virulence factors. We propose that high-throughput assays for functional virulence trait identification should become a prominent method of characterizing bacterial pathogens on a population scale. This work is critical as we move from compiling lists of bacterial species associated with disease to pathogen-agnostic approaches capable of detecting novel microbes. We discuss six key areas of functional trait testing and how advancing high-throughput methods could provide a greater understanding of pathogens.
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Affiliation(s)
- Zachary R. Stromberg
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Shelby M. B. Phillips
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Kristin M. Omberg
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Becky M. Hess
- Chemical and Biological Signatures Group, Pacific Northwest National Laboratory, Richland, Washington, USA
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3
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Sheng H, Wu S, Xue Y, Zhao W, Caplan AB, Hovde CJ, Minnich SA. Engineering conjugative CRISPR-Cas9 systems for the targeted control of enteric pathogens and antibiotic resistance. PLoS One 2023; 18:e0291520. [PMID: 37699034 PMCID: PMC10497133 DOI: 10.1371/journal.pone.0291520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Pathogenic Escherichia coli and Salmonella enterica pose serious public health threats due to their ability to cause severe gastroenteritis and life-threatening sequela, particularly in young children. Moreover, the emergence and dissemination of antibiotic resistance in these bacteria have complicated control of infections. Alternative strategies that effectively target these enteric pathogens and negate or reduce the need of antibiotics are urgently needed. Such an alternative is the CRISPR-Cas9 system because it can generate sequence-specific lethal double stranded DNA breaks. In this study, two self-transmissible broad host range conjugative plasmids, pRK24 and pBP136, were engineered to deliver multiplexed CRSIPR-Cas9 systems that specifically target Enterohemorrhagic and Enteropathogenic strains of E. coli (EHEC and EPEC), S. enterica, and blaCMY-2 antibiotic resistance plasmids. Using in vitro mating assays, we show that the conjugative delivery of pRK24-CRISPR-Cas9 carrying guide RNAs to the EPEC/EHEC eae (intimin) gene can selectively kill enterohemorrhagic E. coli O157 eae+ cells (3 log kill at 6 h) but does not kill the isogenic Δeae mutant (P<0.001). Similar results were also obtained with a pBP136 derivative, pTF16, carrying multiplexed guide RNAs targeting E. coli eae and the S. enterica ssaN gene coding for the type III secretion ATPase. Another pBP136 derivative, TF18, carries guide RNAs targeting S. enterica ssaN and the antibiotic resistance gene, blaCMY-2, carried on the multi-drug resistant pAR06302. Introduction of pTF18 into bacteria harboring pAR06302 showed plasmids were cured at an efficiency of 53% (P<0.05). Using a murine neonate EPEC infection model, pTF16 was delivered by a murine derived E. coli strain to EPEC infected mice and showed significant reductions of intestinal EPEC (P<0.05). These results suggest that establishing conjugative CRISPR-Cas9 antimicrobials in the intestinal microbiome may provide protection from enteric pathogens and reduce antibiotic resistance without disrupting the normal microbiota.
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Affiliation(s)
- Haiqing Sheng
- Animal, Veterinary and Food Science, University of Idaho, Moscow, Idaho, United States of America
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, Idaho, United States of America
| | - Sarah Wu
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, Idaho, United States of America
| | - Yansong Xue
- Animal, Veterinary and Food Science, University of Idaho, Moscow, Idaho, United States of America
| | - Wei Zhao
- Animal, Veterinary and Food Science, University of Idaho, Moscow, Idaho, United States of America
| | - Allan B. Caplan
- Department of Plant Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Carolyn J. Hovde
- Animal, Veterinary and Food Science, University of Idaho, Moscow, Idaho, United States of America
| | - Scott A. Minnich
- Animal, Veterinary and Food Science, University of Idaho, Moscow, Idaho, United States of America
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4
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Wi SM, Kim SK, Lee JB, Yoon JW. Acid tolerance of enterohemorrhagic Escherichia coli O157:H7 strain ATCC 43894 and its relationship with a large virulence plasmid pO157. Vet Microbiol 2023; 284:109833. [PMID: 37515979 DOI: 10.1016/j.vetmic.2023.109833] [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: 02/08/2023] [Revised: 06/19/2023] [Accepted: 07/17/2023] [Indexed: 07/31/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen that causes a severe intestinal infection including hemolytic uremic syndrome in humans. Various factors contribute to its pathogenesis, including a large virulence plasmid pO157. This F-like 92-kb plasmid is isolated in virtually all clinical EHEC isolates, and is considered a hallmark of EHEC virulence. A previous report stated that removal of pO157 from EHEC ATCC 43894 induced overexpression of GadAB that are essential in glutamate-dependent acid resistance (GDAR) system, yet the mechanism remains elusive. Based on this observation, we surmised that pO157 is involved in the regulation of GDAR system. We comparatively analyzed 43894 and its pO157-cured (ΔpO157) mutant 277 for i) their acid resistance, ii) changes in the transcriptional profiles and iii) expression of GDAR associated genes/proteins. Survivability of 43894 upon exposure to acidic conditions was significantly lower than the ΔpO157 mutant. In addition, RNA-sequencing revealed that genes involved in GDAR were significantly down-regulated in 43894 when compared to the ΔpO157 mutant. Exogenous expression of GadE in 43894 led to expression of GadAB, suggesting possible intervention of pO157 in GDAR regulation. Despite these findings, reintroduction of pO157 into 277 did not reverted Gad overexpression. Likewise, removing pO157 from 43894 using the plasmid incompatibility method did not induce Gad overexpression as shown in 277. Taken together, the results suggest that variation in acid resistance among EHEC isolates exists, and the large virulence plasmid pO157 has no effect on weak acid resistance phenotype displayed in 43894.
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Affiliation(s)
- Seon Mi Wi
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Se Kye Kim
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jun Bong Lee
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jang Won Yoon
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea.
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Kudva IT, Biernbaum EN, Cassmann ED, Palmer MV. Bovine Rectoanal Junction In Vitro Organ Culture Model System to Study Shiga Toxin-Producing Escherichia coli Adherence. Microorganisms 2023; 11:1289. [PMID: 37317263 DOI: 10.3390/microorganisms11051289] [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: 04/14/2023] [Revised: 04/27/2023] [Accepted: 05/06/2023] [Indexed: 06/16/2023] Open
Abstract
Studies evaluating the interactions between Shiga toxin-producing Escherichia coli O157:H7 (O157) and the bovine recto-anal junction (RAJ) have been limited to either in vitro analyses of bacteria, cells, or nucleic acids at the RAJ, providing limited information. Alternatively, expensive in vivo studies in animals have been conducted. Therefore, our objective was to develop a comprehensive in vitro organ culture system of the RAJ (RAJ-IVOC) that accurately represents all cell types present in the RAJ. This system would enable studies that yield results similar to those observed in vivo. Pieces of RAJ tissue, obtained from unrelated cattle necropsies, were assembled and subjected to various tests in order to determine the optimal conditions for assaying bacterial adherence in a viable IVOC. O157 strain EDL933 and E. coli K12 with known adherence differences were used to standardize the RAJ-IVOC adherence assay. Tissue integrity was assessed using cell viability, structural cell markers, and histopathology, while the adherence of bacteria was evaluated via microscopy and culture methods. DNA fingerprinting verified the recovered bacteria against the inoculum. When the RAJ-IVOC was assembled in Dulbecco's Modified Eagle Medium, maintained at a temperature of 39 °C with 5% CO2 and gentle shaking for a duration of 3-4 h, it successfully preserved tissue integrity and reproduced the expected adherence phenotype of the bacteria being tested. The RAJ-IVOC model system provides a convenient method to pre-screen multiple bacteria-RAJ interactions prior to in vivo experiments, thereby reducing animal usage.
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Affiliation(s)
- Indira T Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
| | - Erika N Biernbaum
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
- Oak Ridge Institute for Science and Education, Oak Ridge, TN 37830, USA
| | - Eric D Cassmann
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
| | - Mitchell V Palmer
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
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Singha S, Thomas R, Viswakarma JN, Gupta VK. Foodborne illnesses of Escherichia coli O157origin and its control measures. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2023; 60:1274-1283. [PMID: 36936116 PMCID: PMC10020406 DOI: 10.1007/s13197-022-05381-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 01/12/2022] [Accepted: 01/21/2022] [Indexed: 12/31/2022]
Abstract
Foodborne illnesses are leading source of morbidity and mortality in both developed and developing nations. Escherichia coli O157 is one of the most reported foodborne pathogen that emerged in the past few decades. South East Asia region suffers the highest average burden of diarrhoeal mortality, especially when it comes to child mortality.Query Many studies were undertaken in the developed nations to evaluate the role of E. coli O157 as one of the etiological agent in foodborne outbreaks. In this article, we discuss the distribution of E. coli O157 serotype in the food chains of South East Asian countries, with a special focus on India where more than half a million child diarrhoeal deaths occurs every year and the reasons for which is often not ascertained to the fullest extent. The article also describes in detail about the various detection methods and control measures with respect to E. coli O157. The aim of this study is to document and highlight the extent of Foodborne infections of E. coli O157 origin and thereby taking effective and proactive preventive measures.
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Affiliation(s)
- Songeeta Singha
- Food Quality Control Laboratory, ICAR-National Research Centre on Pig, Rani, Guwahati, Assam 781131 India
| | - Rajendran Thomas
- Food Quality Control Laboratory, ICAR-National Research Centre on Pig, Rani, Guwahati, Assam 781131 India
| | - Jai Narain Viswakarma
- Assam Don Bosco University, Tapesia Gardens, Kamarkuchi, Sonapur, Assam 782402 India
| | - Vivek Kumar Gupta
- Food Quality Control Laboratory, ICAR-National Research Centre on Pig, Rani, Guwahati, Assam 781131 India
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Gambushe SM, Zishiri OT, El Zowalaty ME. Review of Escherichia coli O157:H7 Prevalence, Pathogenicity, Heavy Metal and Antimicrobial Resistance, African Perspective. Infect Drug Resist 2022; 15:4645-4673. [PMID: 36039321 PMCID: PMC9420067 DOI: 10.2147/idr.s365269] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 06/23/2022] [Indexed: 12/02/2022] Open
Abstract
Escherichia coli O157:H7 is an important food-borne and water-borne pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome in humans and may cause serious morbidity and large outbreaks worldwide. People with bloody diarrhea have an increased risk of developing serious complications such as acute renal failure and neurological damage. The hemolytic-uremic syndrome (HUS) is a serious condition, and up to 50% of HUS patients can develop long-term renal dysfunction or blood pressure-related complications. Children aged two to six years have an increased risk of developing HUS. Clinical enteropathogenic Escherichia coli (EPEC) infections show fever, vomiting, and diarrhea. The EPEC reservoir is unknown but is suggested to be an asymptomatic or symptomatic child or an asymptomatic adult carrier. Spreading is often through the fecal-oral route. The prevalence of EPEC in infants is low, and EPEC is highly contagious in children. EPEC disease in children tends to be clinically more severe than other diarrheal infections. Some children experience persistent diarrhea that lasts for more than 14 days. Enterotoxigenic Escherichia coli (ETEC) strains are a compelling cause of the problem of diarrheal disease. ETEC strains are a global concern as the bacteria are the leading cause of acute watery diarrhea in children and the leading cause of traveler’s diarrhea. It is contagious to children and can cause chronic diarrhea that can affect the development and well-being of children. Infections with diarrheagenic E. coli are more common in African countries. Antimicrobial agents should be avoided in the acute phase of the disease since studies showed that antimicrobial agents may increase the risk of HUS in children. The South African National Veterinary Surveillance and Monitoring Programme for Resistance to Antimicrobial Drugs has reported increased antimicrobial resistance in E. coli. Pathogenic bacterial strains have developed resistance to a variety of antimicrobial agents due to antimicrobial misuse. The induced heavy metal tolerance may also enhance antimicrobial resistance. The prevalence of antimicrobial resistance depends on the type of the antimicrobial agent, bacterial strain, dose, time, and mode of administration. Developing countries are severely affected by increased resistance to antimicrobial agents due to poverty, lack of proper hygiene, and clean water, which can lead to bacterial infections with limited treatment options due to resistance.
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Affiliation(s)
- Sydney M Gambushe
- School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Oliver T Zishiri
- School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
| | - Mohamed E El Zowalaty
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, SE 75 123, Sweden
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Escherichia coli 0157:H7 virulence factors and the ruminant reservoir. Curr Opin Infect Dis 2022; 35:205-214. [PMID: 35665714 PMCID: PMC9302714 DOI: 10.1097/qco.0000000000000834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review updates recent findings about Escherichia coli O157:H7 virulence factors and its bovine reservoir. This Shiga toxin (Stx)-producing E. coli belongs to the Enterohemorrhagic E. coli (EHEC) pathotype causing hemorrhagic colitis. Its low infectious dose makes it an efficient, severe, foodborne pathogen. Although EHEC remains in the intestine, Stx can translocate systemically and is cytotoxic to microvascular endothelial cells, especially in the kidney and brain. Disease can progress to life-threatening hemolytic uremic syndrome (HUS) with hemolytic anemia, acute kidney failure, and thrombocytopenia. Young children, the immunocompromised, and the elderly are at the highest risk for HUS. Healthy ruminants are the major reservoir of EHEC and cattle are the primary source of human exposure. RECENT FINDINGS Advances in understanding E. coli O157:H7 pathogenesis include molecular mechanisms of virulence, bacterial adherence, type three secretion effectors, intestinal microbiome, inflammation, and reservoir maintenance. SUMMARY Many aspects of E. coli O157:H7 disease remain unclear and include the role of the human and bovine intestinal microbiomes in infection. Therapeutic strategies involve controlling inflammatory responses and/or intestinal barrier function. Finally, elimination/reduction of E. coli O157:H7 in cattle using CRISPR-engineered conjugative bacterial plasmids and/or on-farm management likely hold solutions to reduce infections and increase food safety/security.
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10
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Unger P, Sekhon AS, Chen X, Michael M. Developing an affordable hyperspectral imaging system for rapid identification of Escherichia coli O157:H7 and Listeria monocytogenes in dairy products. Food Sci Nutr 2022; 10:1175-1183. [PMID: 35432977 PMCID: PMC9007299 DOI: 10.1002/fsn3.2749] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/29/2021] [Accepted: 01/02/2022] [Indexed: 01/31/2023] Open
Abstract
The objective of this foundational study was to develop and evaluate the efficacy of an affordable hyperspectral imaging (HSI) system to identify single and mixed strains of foodborne pathogens in dairy products. This study was designed as a completely randomized design with three replications. Three strains each of Escherichia coli O157:H7 and Listeria monocytogenes were evaluated either as single or mixed strains with the HSI system in growth media and selected dairy products (whole milk, and cottage and cheddar cheeses). Test samples from freshly prepared single or mixed strains of pathogens in growth media or inoculated dairy products were streaked onto selective media (PALCAM and/or Sorbitol MacConkey agar) for isolation. An isolated colony was selected and mixed with 1 ml of HPLC grade water, vortexed for 1 min, and spread over a microscope slide. Images were captured at 2000× magnification on the built HSI system at wavelengths ranging from 400 nm to 1100 nm with 5‐nm band intervals. For each image, three cells were selected as regions of interest (ROIs) to obtain hyperspectral signatures of respective bacteria. Reference pathogen libraries were created using growth media, and then test pathogenic cells were classified by their hyperspectral signatures as either L. monocytogenes or E. coli O157:H7 using k‐nearest neighbor (kNN) and cross‐validation technique in R‐software. With the implementation of kNN (k = 3), overall classification accuracies of 58.97% and 61.53% were obtained for E. coli O157:H7 and L. monocytogenes, respectively.
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Affiliation(s)
- Phoebe Unger
- School of Food Science Washington State University Pullman Washington USA
| | | | - Xiongzhi Chen
- Department of Mathematics and Statistics Washington State University Pullman Washington USA
| | - Minto Michael
- School of Food Science Washington State University Pullman Washington USA
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Wan Y, Zong C, Li X, Wang A, Li Y, Yang T, Bao Q, Dubow M, Yang M, Rodrigo LA, Mao C. New Insights for Biosensing: Lessons from Microbial Defense Systems. Chem Rev 2022; 122:8126-8180. [PMID: 35234463 DOI: 10.1021/acs.chemrev.1c01063] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Microorganisms have gained defense systems during the lengthy process of evolution over millions of years. Such defense systems can protect them from being attacked by invading species (e.g., CRISPR-Cas for establishing adaptive immune systems and nanopore-forming toxins as virulence factors) or enable them to adapt to different conditions (e.g., gas vesicles for achieving buoyancy control). These microorganism defense systems (MDS) have inspired the development of biosensors that have received much attention in a wide range of fields including life science research, food safety, and medical diagnosis. This Review comprehensively analyzes biosensing platforms originating from MDS for sensing and imaging biological analytes. We first describe a basic overview of MDS and MDS-inspired biosensing platforms (e.g., CRISPR-Cas systems, nanopore-forming proteins, and gas vesicles), followed by a critical discussion of their functions and properties. We then discuss several transduction mechanisms (optical, acoustic, magnetic, and electrical) involved in MDS-inspired biosensing. We further detail the applications of the MDS-inspired biosensors to detect a variety of analytes (nucleic acids, peptides, proteins, pathogens, cells, small molecules, and metal ions). In the end, we propose the key challenges and future perspectives in seeking new and improved MDS tools that can potentially lead to breakthrough discoveries in developing a new generation of biosensors with a combination of low cost; high sensitivity, accuracy, and precision; and fast detection. Overall, this Review gives a historical review of MDS, elucidates the principles of emulating MDS to develop biosensors, and analyzes the recent advancements, current challenges, and future trends in this field. It provides a unique critical analysis of emulating MDS to develop robust biosensors and discusses the design of such biosensors using elements found in MDS, showing that emulating MDS is a promising approach to conceptually advancing the design of biosensors.
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Affiliation(s)
- Yi Wan
- State Key Laboratory of Marine Resource Utilization in the South China Sea, School of Pharmaceutical Sciences, Marine College, Hainan University, Haikou 570228, P. R. China
| | - Chengli Zong
- State Key Laboratory of Marine Resource Utilization in the South China Sea, School of Pharmaceutical Sciences, Marine College, Hainan University, Haikou 570228, P. R. China
| | - Xiangpeng Li
- Department of Bioengineering and Therapeutic Sciences, Schools of Medicine and Pharmacy, University of California, San Francisco, 1700 Fourth Street, Byers Hall 303C, San Francisco, California 94158, United States
| | - Aimin Wang
- State Key Laboratory of Marine Resource Utilization in the South China Sea, School of Pharmaceutical Sciences, Marine College, Hainan University, Haikou 570228, P. R. China
| | - Yan Li
- College of Animal Science, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
| | - Tao Yang
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
| | - Qing Bao
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
| | - Michael Dubow
- Institute for Integrative Biology of the Cell (I2BC), UMR 9198 CNRS, CEA, Université Paris-Saclay, Campus C.N.R.S, Bâtiment 12, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France
| | - Mingying Yang
- College of Animal Science, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
| | - Ledesma-Amaro Rodrigo
- Imperial College Centre for Synthetic Biology, Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Chuanbin Mao
- Department of Chemistry & Biochemistry, Stephenson Life Science Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States.,School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China
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12
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Pan Z, Chen Y, Zhou M, McAllister TA, Guan LL. Microbial interaction-driven community differences as revealed by network analysis. Comput Struct Biotechnol J 2021; 19:6000-6008. [PMID: 34849204 PMCID: PMC8599104 DOI: 10.1016/j.csbj.2021.10.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/23/2021] [Accepted: 10/28/2021] [Indexed: 01/04/2023] Open
Abstract
Diversity and compositional analysis are the most common approaches in deciphering microbial community differences. However, these approaches neglect microbial structural differences driven by microbial interactions. In this study, the microbiota data were generated from 12 rectal digesta samples collected from steers in which the Shiga toxin 2 gene (stx2) was not expressed (defined as Stx2- group) in the bacteria, and those with stx2 expressed (defined as Stx2+ group) and used to explore whether microbial networks affect gut microbiota and foodborne pathogen virulence in cattle. Although the Shannon and Chao1 indices of rectal digesta microbial communities did not differ between the two groups (P > 0.05), 24 and 13 taxa were identified to be group-specific genera for Stx2- and Stx2+ microbial communities, respectively. The network analysis indicated 12 and 14 generalists (microbes that were densely connected with other taxa) in microbial communities for Stx2- and Stx2+ groups, and 8 out of 12 generalists and 6 out of 14 generalists were designated to Stx2- and Stx2+ group-specific genera, respectively. However, the 66 core genera were not classified as network generalists. Natural connectivity measurements revealed that the higher stability of the Stx2- microbial network in comparison to the Stx2+ network, suggesting that the structure of each microbial community was inherently different even when their diversity and composition were comparable. Group-specific genera intensely interacted with other taxa in the co-occurrence network, indicating that characterizing microbial networks together with group-specific genera could be an alternative approach to identify variation in microbial communities.
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Affiliation(s)
- Zhe Pan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Yanhong Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Mi Zhou
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Tim A McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada
| | - Le Luo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
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Lee KS, Jeong YJ, Lee MS. Escherichia coli Shiga Toxins and Gut Microbiota Interactions. Toxins (Basel) 2021; 13:toxins13060416. [PMID: 34208170 PMCID: PMC8230793 DOI: 10.3390/toxins13060416] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 12/19/2022] Open
Abstract
Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are enterohemorrhagic bacteria that induce hemorrhagic colitis. This, in turn, may result in potentially lethal complications, such as hemolytic uremic syndrome (HUS), which is characterized by thrombocytopenia, acute renal failure, and neurological abnormalities. Both species of bacteria produce Shiga toxins (Stxs), a phage-encoded exotoxin inhibiting protein synthesis in host cells that are primarily responsible for bacterial virulence. Although most studies have focused on the pathogenic roles of Stxs as harmful substances capable of inducing cell death and as proinflammatory factors that sensitize the host target organs to damage, less is known about the interface between the commensalism of bacterial communities and the pathogenicity of the toxins. The gut contains more species of bacteria than any other organ, providing pathogenic bacteria that colonize the gut with a greater number of opportunities to encounter other bacterial species. Notably, the presence in the intestines of pathogenic EHEC producing Stxs associated with severe illness may have compounding effects on the diversity of the indigenous bacteria and bacterial communities in the gut. The present review focuses on studies describing the roles of Stxs in the complex interactions between pathogenic Shiga toxin-producing E. coli, the resident microbiome, and host tissues. The determination of these interactions may provide insights into the unresolved issues regarding these pathogens.
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Affiliation(s)
- Kyung-Soo Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, Korea;
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea
| | - Yu-Jin Jeong
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, Korea;
- Correspondence: (Y.-J.J.); (M.-S.L.)
| | - Moo-Seung Lee
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Daejeon 34141, Korea;
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology (UST), 127 Gajeong-ro, Yuseong-gu, Daejeon 34113, Korea
- Correspondence: (Y.-J.J.); (M.-S.L.)
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14
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Yu D, Banting G, Neumann NF. A review of the taxonomy, genetics, and biology of the genus Escherichia and the type species Escherichia coli. Can J Microbiol 2021; 67:553-571. [PMID: 33789061 DOI: 10.1139/cjm-2020-0508] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Historically, bacteriologists have relied heavily on biochemical and structural phenotypes for bacterial taxonomic classification. However, advances in comparative genomics have led to greater insights into the remarkable genetic diversity within the microbial world, and even within well-accepted species such as Escherichia coli. The extraordinary genetic diversity in E. coli recapitulates the evolutionary radiation of this species in exploiting a wide range of niches (i.e., ecotypes), including the gastrointestinal system of diverse vertebrate hosts as well as non-host natural environments (soil, natural waters, wastewater), which drives the adaptation, natural selection, and evolution of intragenotypic conspecific specialism as a strategy for survival. Over the last few years, there has been increasing evidence that many E. coli strains are very host (or niche)-specific. While biochemical and phylogenetic evidence support the classification of E. coli as a distinct species, the vast genomic (diverse pan-genome and intragenotypic variability), phenotypic (e.g., metabolic pathways), and ecotypic (host-/niche-specificity) diversity, comparable to the diversity observed in known species complexes, suggest that E. coli is better represented as a complex. Herein we review the taxonomic classification of the genus Escherichia and discuss how phenotype, genotype, and ecotype recapitulate our understanding of the biology of this remarkable bacterium.
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Affiliation(s)
- Daniel Yu
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Graham Banting
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
| | - Norman F Neumann
- School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada.,School of Public Health, University of Alberta, Edmonton, AB T6G IC9, Canada
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15
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Pan Z, Chen Y, McAllister TA, Gänzle M, Plastow G, Guan LL. Abundance and Expression of Shiga Toxin Genes in Escherichia coli at the Recto-Anal Junction Relates to Host Immune Genes. Front Cell Infect Microbiol 2021; 11:633573. [PMID: 33816337 PMCID: PMC8010187 DOI: 10.3389/fcimb.2021.633573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/15/2021] [Indexed: 12/01/2022] Open
Abstract
Shiga toxin (Stx) is the main virulence factor of Shiga toxin-producing Escherichia coli (STEC), and ruminants are the main reservoir of STEC. This study assessed the abundance and expression of Stx genes and the expression of host immune genes, aiming to determine factors affecting these measures and potential gene markers to differentiate Stx gene expression in the recto-anal junction of feedlot beef cattle. Rectal tissue and content samples were collected from 143 feedlot steers of three breeds (Angus, Charolais, and Kinsella Composite) over 2 consecutive years 2014 (n=71) and 2015 (n=72). The abundance and expression of stx1 and stx2 were quantified using qPCR and reverse-transcription-qPCR (RT-qPCR), respectively. Four immune genes (MS4A1, CCL21, CD19, and LTB), previously reported to be down-regulated in super-shedder cattle (i.e., > 104 CFU g-1) were selected, and their expression was evaluated using RT-qPCR. The stx1 gene abundance was only detected in tissue samples collected in year 2 and did not differ among breeds. The stx2 gene was detected in STEC from all samples collected in both years and did not vary among breeds. The abundance of stx1 and stx2 differed (P < 0.001) in content samples collected across breeds (stx1:AN>CH>KC, stx2: AN=CH>KC) in year 1, but not in year 2. Expression of stx2 was detected in 13 RAJ tissue samples (2014: n=6, 2015: n=7), while expression of stx1 was not detected. Correlation analysis showed that the expression of stx2 was negatively correlated with the expression of MS4A1 (R=-0.56, P=0.05) and positively correlated with the expression of LTB (R=0.60, P=0.05). The random forest model and Boruta method revealed that expression of selected immune genes could be predictive indicators of stx2 expression with prediction accuracy of MS4A1 >LTB >CCL21 >CD19. Our results indicate that the abundance of Stx could be affected by cattle breed and sampling year, suggesting that host genetics and environment may influence STEC colonization of the recto-anal junction of feedlot cattle. Additionally, the identified relationship between expressions of host immune genes and stx2 suggests that the host animal may regulate stx2 expression in colonizing STEC through immune functions.
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Affiliation(s)
- Zhe Pan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Yanhong Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Tim A McAllister
- Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Graham Plastow
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Le Luo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
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Nonfimbrial Adhesin Mutants Reveal Divergent Escherichia coli O157:H7 Adherence Mechanisms on Human and Cattle Epithelial Cells. Int J Microbiol 2021; 2021:8868151. [PMID: 33574851 PMCID: PMC7864753 DOI: 10.1155/2021/8868151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 01/08/2021] [Indexed: 11/17/2022] Open
Abstract
Shiga toxin-producing, enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a major foodborne pathogen causing symptoms ranging from simple intestinal discomfort to bloody diarrhea and life-threatening hemolytic uremic syndrome in humans. Cattle can be asymptomatically colonized by O157:H7 predominantly at the rectoanal junction (RAJ). Colonization of the RAJ is highly associated with the shedding of O157:H7 in bovine feces. Supershedding (SS) is a phenomenon that has been reported in some cattle that shed more than 104 colony-forming units of O57:H7 per gram of feces, 100–1000 times more or greater than normal shedders. The unique bovine RAJ cell adherence model revealed that O157:H7 employs a LEE-independent mechanism of attachment to one of the RAJ cell types, the squamous epithelial (RSE) cells. Nine nonfimbrial adhesins were selected to determine their role in the characteristic hyperadherent phenotype of SS O157 on bovine RSE cells, in comparison with human HEp-2 cells. A number of single nucleotide polymorphisms (SNPs) were found amongst these nonfimbrial adhesins across a number of SS isolates. In human cells, deletion of yfaL reduced the adherence of both EDL933 and SS17. However, deletion of eae resulted in a significant loss of adherence in SS17 whereas deletion of wzzB and iha in EDL933 resulted in the same loss of adherence to HEp-2 cells. On RSE cells, none of these nonfimbrial deletion mutants were able to alter the adherence phenotype of SS17. In EDL933, deletion of cah resulted in mitigated adherence. Surprisingly, four nonfimbrial adhesin gene deletions were actually able to confer the hyperadherent phenotype on RSE cells. Overall, this study reveals that the contribution of nonfimbrial adhesins to the adherence mechanisms and functions of O157:H7 is both strain and host cell type dependent as well as indicates a possible role of these nonfimbrial adhesins in the SS phenotype exhibited on RSE cells.
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Repeated Oral Vaccination of Cattle with Shiga Toxin-Negative Escherichia coli O157:H7 Reduces Carriage of Wild-Type E. coli O157:H7 after Challenge. Appl Environ Microbiol 2021; 87:AEM.02183-20. [PMID: 33158889 DOI: 10.1128/aem.02183-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022] Open
Abstract
Subcutaneous vaccination of cattle for enterohemorrhagic Escherichia coli O157:H7 reduces the magnitude and duration of fecal shedding, but the often-required, repeated cattle restraint can increase costs, deterring adoption by producers. In contrast, live oral vaccines may be repeatedly administered in feed, without animal restraint. We investigated whether oral immunization with live stx-negative LEE+ E. coli O157:H7 reduced rectoanal junction (RAJ) colonization by wild-type (WT) E. coli O157:H7 strains after challenge. Two groups of cattle were orally dosed twice weekly for 6 weeks with 3 × 109 CFU of a pool of three stx-negative LEE+ E. coli O157:H7 strains (vaccine group) or three stx-negative LEE- non-O157:H7 E. coli strains (control group). Three weeks following the final oral dose, animals in both groups were orally challenged with a cocktail of four stx+ LEE+ E. coli O157:H7 WT strains. Subsequently, WT strains at the RAJ were enumerated weekly for 4 weeks. Serum antibodies against type III secretion protein (TTSP), the translocated intimin receptor (Tir), and EspA were determined by enzyme-linked immunosorbent assay (ELISA) at day 0 (preimmunization), day 61 (postimmunization, prechallenge), and day 89 (postchallenge). Vaccine group cattle had lower numbers of WT strains at the RAJ than control group cattle on postchallenge days 3 and 7 (P ≤ 0.05). Also, vaccine group cattle shed WT strains for a shorter duration than control group cattle. All cattle seroconverted to TTSP, Tir, and EspA, either following immunization (vaccine group) or following challenge (control group). Increased antibody titers against Tir and TTSP postimmunization were associated with decreased numbers of WT E. coli O157:H7 organisms at the RAJ.IMPORTANCE The bacterium E. coli O157:H7 causes foodborne disease in humans that can lead to bloody diarrhea, kidney failure, vascular damage, and death. Healthy cattle are the main source of this human pathogen. Reducing E. coli O157:H7 in cattle will reduce human disease. Using a randomized comparison, a bovine vaccine to reduce carriage of the human pathogen was tested. A detoxified E. coli O157:H7 strain, missing genes that cause disease, was fed to cattle as an oral vaccine to reduce carriage of pathogenic E. coli O157:H7. After vaccination, the cattle were challenged with disease-causing E. coli O157:H7. The vaccinated cattle had decreased E. coli O157:H7 during the first 7 days postchallenge and shed the bacteria for a shorter duration than the nonvaccinated control cattle. The results support optimization of the approach to cattle vaccination that would reduce human disease.
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18
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Genetic and Phenotypic Factors Associated with Persistent Shedding of Shiga Toxin-Producing Escherichia coli by Beef Cattle. Appl Environ Microbiol 2020; 86:AEM.01292-20. [PMID: 32769184 DOI: 10.1128/aem.01292-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/01/2020] [Indexed: 12/14/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a leading cause of foodborne infections. Cattle are an important STEC reservoir, although little is known about specific pathogen traits that impact persistence in the farm environment. Hence, we sought to evaluate STEC isolates recovered from beef cattle in a single herd in Michigan. To do this, we collected fecal grabs from 26 cattle and resampled 13 of these animals at 3 additional visits over a 3-month period. In all, 66 STEC isolates were recovered for genomics and biofilm quantification using crystal violet assays. The STEC population was diverse, representing seven serotypes, including O157:H7, O26:H11, and O103:H2, which are commonly associated with human infections. Although a core genome analysis of 2,933 genes grouped isolates into clusters based on serogroups, some isolates within each cluster had variable biofilm levels and virulence gene profiles. Most (77.8%; n = 49) isolates harbored stx 2a, while 38 (57.5%) isolates formed strong biofilms. Isolates belonging to the predominant serogroup O6 (n = 36; 54.5%) were more likely to form strong biofilms, persistently colonize multiple cattle, and be acquired over time. A high-quality single nucleotide polymorphism (SNP) analysis of 33 O6 isolates detected between 0 and 13 single nucleotide polymorphism (SNP) differences between strains, indicating that highly similar strain types were persisting in this herd. Similar findings were observed for other persistent serogroups, although key genes were found to differ among strong and weak biofilm producers. Together, these data highlight the diversity and persistent nature of some STEC types in this important food animal reservoir.IMPORTANCE Food animal reservoirs contribute to Shiga toxin-producing Escherichia coli (STEC) evolution via the acquisition of horizontally acquired elements like Shiga toxin bacteriophages that enhance pathogenicity. In cattle, persistent fecal shedding of STEC contributes to contamination of beef and dairy products and to crops being exposed to contaminated water systems. Hence, identifying factors important for STEC persistence is critical. This longitudinal study enhances our understanding of the genetic diversity of STEC types circulating in a cattle herd and identifies genotypic and phenotypic traits associated with persistence. Key findings demonstrate that multiple STEC types readily persist in and are transmitted across cattle in a shared environment. These dynamics also enhance the persistence of virulence genes that can be transferred between bacterial hosts, resulting in the emergence of novel STEC strain types. Understanding how pathogens persist and diversify in reservoirs is important for guiding new preharvest prevention strategies aimed at reducing foodborne transmission to humans.
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19
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Menge C. The Role of Escherichia coli Shiga Toxins in STEC Colonization of Cattle. Toxins (Basel) 2020; 12:toxins12090607. [PMID: 32967277 PMCID: PMC7551371 DOI: 10.3390/toxins12090607] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 11/20/2022] Open
Abstract
Many cattle are persistently colonized with Shiga toxin-producing Escherichia coli (STEC) and represent a major source of human infections with human-pathogenic STEC strains (syn. enterohemorrhagic E. coli (EHEC)). Intervention strategies most effectively protecting humans best aim at the limitation of bovine STEC shedding. Mechanisms enabling STEC to persist in cattle are only partialy understood. Cattle were long believed to resist the detrimental effects of Shiga toxins (Stxs), potent cytotoxins acting as principal virulence factors in the pathogenesis of human EHEC-associated diseases. However, work by different groups, summarized in this review, has provided substantial evidence that different types of target cells for Stxs exist in cattle. Peripheral and intestinal lymphocytes express the Stx receptor globotriaosylceramide (Gb3syn. CD77) in vitro and in vivo in an activation-dependent fashion with Stx-binding isoforms expressed predominantly at early stages of the activation process. Subpopulations of colonic epithelial cells and macrophage-like cells, residing in the bovine mucosa in proximity to STEC colonies, are also targeted by Stxs. STEC-inoculated calves are depressed in mounting appropriate cellular immune responses which can be overcome by vaccination of the animals against Stxs early in life before encountering STEC. Considering Stx target cells and the resulting effects of Stxs in cattle, which significantly differ from effects implicated in human disease, may open promising opportunities to improve existing yet insufficient measures to limit STEC carriage and shedding by the principal reservoir host.
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Affiliation(s)
- Christian Menge
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, D-07743 Jena, Germany
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20
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Quiguanás-Guarín E, Granobles-Velandia C, Arango-Gil B, Giraldo-Rubio V, Castaño-Osorio J. Aislamiento de Escherichia coli productora de toxina Shiga (STEC) en heces de ganado y detección de factores de virulencia asociados con su patogénesis. INFECTIO 2020. [DOI: 10.22354/in.v25i1.906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objetivo: Aislar STEC en las heces del ganado bovino en el municipio de Ulloa, Valle del Cauca y detectar factores de virulencia asociados con la patogénesis. Materiales y métodos: Se tomaron 21 muestras provenientes de bovinos, las cuales fueron tomadas directamente del recto del animal mediante hisopos. Las muestras se procesaron hasta obtener colonias puras a las cuales se les evaluó la presencia de los genes stx1, stx2, eae, saa y hlyA mediante PCR y posteriormente, se evaluó el efecto citotóxico de las muestras positivas sobre células Vero (ATCC-CCL-81.4). Resultados: De las 21 muestras de heces de bovinos,12 presentaron bacterias con uno o ambos genes stx. Se obtuvieron 106 aislamientos totales de STEC y se observaron diferencias en cuanto a la presencia y ausencia de los genes de virulencia evaluados en los aislamientos de cada bovino, obteniendo cinco combinaciones de genes. 48 aislamientos presentaron únicamente el gen stx2 y 58 presentaron tanto el gen stx1 como el gen stx2; de los 106 aislamientos, se detectaron 44 con el gen hlyA y 57 con el gen saa. Conclusiones: Todos los sobrenadantes de STEC analizados mostraron actividad citotóxica sobre las células Vero, mientras que en ausencia de STEC las células formaron monocapa después de 48 h de incubación. Este trabajo es el primer reporte en Colombia que aporta información sobre la presencia de STEC en el ganado bovino, la presencia de factores de virulencia y el potencial efecto citotóxico que poseen estas cepas nativas.
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Abstract
Escherichia coli is a commensal of the vertebrate gut that is increasingly involved in various intestinal and extra-intestinal infections as an opportunistic pathogen. Numerous pathotypes that represent groups of strains with specific pathogenic characteristics have been described based on heterogeneous and complex criteria. The democratization of whole-genome sequencing has led to an accumulation of genomic data that render possible a population phylogenomic approach to the emergence of virulence. Few lineages are responsible for the pathologies compared with the diversity of commensal strains. These lineages emerged multiple times during E. coli evolution, mainly by acquiring virulence genes located on mobile elements, but in a specific chromosomal phylogenetic background. This repeated emergence of stable and cosmopolitan lineages argues for an optimization of strain fitness through epistatic interactions between the virulence determinants and the remaining genome.
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Teng L, Lee S, Park D, Jeong KC. Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle. Front Cell Infect Microbiol 2020; 10:271. [PMID: 32582570 PMCID: PMC7289925 DOI: 10.3389/fcimb.2020.00271] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/07/2020] [Indexed: 12/19/2022] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been isolated. Here, an STEC O157:H7 isolate, JEONG-1266, was analyzed by comparative genomics, stx genotyping, and phenotypic analyses. The phylogenetic typing and whole-genome comparison consistently showed that JEONG-1266 is genetically close to EC4115 (one of 2006 Spinach outbreak isolates) and SS17 (an isolate from super-shedder cattle) strains, all of which belong to lineage I/II and Clade 8. Both lineage I/II and Clade 8 are known to be mostly associated with clinical strains with high virulence and severe clinical symptoms. Further, JEONG-1266, like EC4115 and SS17, harbors stx2a/stx2c genes, and carries Stx-encoding prophages, specifically the φstx2a-γ subtype. Possession of the φstx2a-γ subtype of Stx-encoding prophages and production of Stx2a have been shown to be a key signature associated with hypervirulent STEC O157:H7 strains. In silico virulence typing elucidated JEONG-1266, EC4115, and SS17 shared a highly conserved profile of key virulence genes at the nucleotide sequence level. Consistently, phenotypic data showed that JEONG-1266 expressed a high level of Stx2 toxins and had the full capacity of adhesion in vitro. Taken together, our study suggests that JEONG-1266 may represent an emerging STEC O157:H7 group, which are hypervirulent strains that originate from super-shedders, that can be a threat to food safety and public health.
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Affiliation(s)
- Lin Teng
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Shinyoung Lee
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Dongjin Park
- Food Science and Technology Department, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Kwangcheol Casey Jeong
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.,Department of Animal Sciences, University of Florida, Gainesville, FL, United States
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Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle. Microorganisms 2020; 8:microorganisms8040580. [PMID: 32316415 PMCID: PMC7232329 DOI: 10.3390/microorganisms8040580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/15/2020] [Indexed: 02/08/2023] Open
Abstract
Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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25
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Whole genome shotgun sequencing revealed highly polymorphic genome regions and genes in Escherichia coli O157:H7 isolates collected from a single feedlot. PLoS One 2018; 13:e0202775. [PMID: 30153286 PMCID: PMC6112667 DOI: 10.1371/journal.pone.0202775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/08/2018] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli serotype O157:H7 continues to pose a serious health threat to human beings. Cattle, a major reservoir of the pathogen, harbor E. coli O157:H7 in their gastrointestinal tract and shed variable concentrations of E. coli O157:H7 into the environment. Genetic characterization of cattle-shed E. coli O157 strains is of interest to the livestock industry, food business, and public health community. The present study applied whole genome shotgun sequencing (WGS) and single nucleotide variant (SNV) calling to characterize 279 cattle-shed E. coli O157:H7 strains isolated from a single feedlot located in southwestern region of the US. More than 4,000 SNVs were identified among the strains and the resultant phylogenomic tree revealed three major groups. Using the Sakai strain genome as reference, more than 2,000 SNVs were annotated and a detailed SNV map generated. Results clearly revealed highly polymorphic loci along the E. coli O157:H7 genome that aligned with the prophage regions and highly variant genes involved in processing bacterial genetic information. The WGS data were further profiled against a comprehensive virulence factor database (VFDB) for virulence gene identification. Among the total 285 virulence genes identified, only 132 were present in all the strains. There were six virulence genes unique to single isolates. Our findings suggested that the genome variations of the E. coli O157:H7 were mainly attributable to dynamics of certain phages, and the bacterial strains have variable virulence gene profiles, even though they came from a single cattle population, which may explain the differences in pathogenicity, host prevalence, and transmissibility by E. coli O157:H7.
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26
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Escherichia coli O157:H7 suppresses host autophagy and promotes epithelial adhesion via Tir-mediated and cAMP-independent activation of protein kinase A. Cell Death Discov 2017; 3:17055. [PMID: 28975041 PMCID: PMC5624281 DOI: 10.1038/cddiscovery.2017.55] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/07/2017] [Indexed: 11/18/2022] Open
Abstract
Autophagy is a pivotal innate immune response that not only degrades cytosolic components, but also serves as one of the critical antimicrobial mechanisms eliminating intracellular pathogens. However, its role in host defense against extracellular pathogens is largely unknown. Here we showed that E. coli O157:H7 altered autophagy to evade host defense and facilitate adhesion. Enhancing host cell autophagy with tumor necrosis factor (TNF), host starvation or rapamycin reduced the adherence of E. coli O157:H7 to HT-29 cells. As a key regulator of autophagy, protein kinase A (PKA) was activated by E. coli O157:H7 infection. PKA inhibition by H89 abrogated E. coli O157:H7 inhibition of autophagy and prevented bacterial epithelial adhesion. Thus, PKA had a mediatory role in blocking autophagy and E. coli O157:H7 epithelial adhesion. Furthermore, deletion of translocated intimin receptor (tir) prevented PKA activation, whereas ectopic tir expression in a Δtir mutant strain restored its ability to activate PKA and inhibited autophagy in host cells. This indicated that Tir and PKA played pivotal roles in manipulating host autophagy during infection. Consistent with autophagy inhibition, E. coli O157:H7 infection inhibited endoplasmic reticulum (ER) stress in HT-29 cells, which was reversed by TNF, starvation, or H89 treatment. Additionally, E. coli O157:H7-induced PKA activation suppressed extracellular signal-regulated kinase 1/2 (ERK1/2) activation and enhanced phosphatidylinositol 3-kinase/Akt (PI3K/Akt) signaling, thereby repressing autophagic signaling. Conversely, PKA inhibition prevented downregulation of ERK1/2 signaling due to E. coli O157:H7 infection. In summary, E. coli O157:H7 inhibited host autophagy via Tir-mediated PKA activation that favored bacterial persistence on intestinal epithelial cell surfaces.
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Lorenz SC, Gonzalez-Escalona N, Kotewicz ML, Fischer M, Kase JA. Genome sequencing and comparative genomics of enterohemorrhagic Escherichia coli O145:H25 and O145:H28 reveal distinct evolutionary paths and marked variations in traits associated with virulence & colonization. BMC Microbiol 2017; 17:183. [PMID: 28830351 PMCID: PMC5567499 DOI: 10.1186/s12866-017-1094-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/14/2017] [Indexed: 12/14/2022] Open
Abstract
Background Enterohemorrhagic Escherichia coli (EHEC) O145 are among the top non-O157 serogroups associated with severe human disease worldwide. Two serotypes, O145:H25 and O145:H28 have been isolated from human patients but little information is available regarding the virulence repertoire, origin and evolutionary relatedness of O145:H25. Hence, we sequenced the complete genome of two O145:H25 strains associated with hemolytic uremic syndrome (HUS) and compared the genomes with those of previously sequenced O145:H28 and other EHEC strains. Results The genomes of the two O145:H25 strains were 5.3 Mbp in size; slightly smaller than those of O145:H28 and other EHEC strains. Both strains contained three nearly identical plasmids and several prophages and integrative elements, many of which differed significantly in size, gene content and organization as compared to those present in O145:H28 and other EHECs. Furthermore, notable variations were observed in several fimbrial gene cluster and intimin types possessed by O145:H25 and O145:H28 indicating potential adaptation to distinct areas of host colonization. Comparative genomics further revealed that O145:H25 are genetically more similar to other non-O157 EHEC strains than to O145:H28. Conclusion Phylogenetic analysis accompanied by comparative genomics revealed that O145:H25 and O145:H28 evolved from two separate clonal lineages and that horizontal gene transfer and gene loss played a major role in the divergence of these EHEC serotypes. The data provide further evidence that ruminants might be a possible reservoir for O145:H25 but that they might be impaired in their ability to establish a persistent colonization as compared to other EHEC strains. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-1094-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra C Lorenz
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, MD, 20740, USA. .,University of Hamburg, Hamburg School of Food Science, Institute of Food Chemistry, 20146, Hamburg, Germany.
| | - Narjol Gonzalez-Escalona
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, MD, 20740, USA
| | - Michael L Kotewicz
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Molecular Biology, Laurel, MD, 20708, USA
| | - Markus Fischer
- University of Hamburg, Hamburg School of Food Science, Institute of Food Chemistry, 20146, Hamburg, Germany
| | - Julie A Kase
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Microbiology, College Park, MD, 20740, USA
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Stein RA, Katz DE. Escherichia coli, cattle and the propagation of disease. FEMS Microbiol Lett 2017; 364:3059138. [PMID: 28333229 PMCID: PMC7108533 DOI: 10.1093/femsle/fnx050] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/28/2017] [Indexed: 12/21/2022] Open
Abstract
Several early models describing host–pathogen interaction have assumed that each individual host has approximately the same likelihood of becoming infected or of infecting others. More recently, a concept that has been increasingly emphasized in many studies is that for many infectious diseases, transmission is not homogeneous but highly skewed at the level of populations. In what became known as the ‘20/80 rule’, about 20% of the hosts in a population were found to contribute to about 80% of the transmission potential. These heterogeneities have been described for the interaction between many microorganisms and their human or animal hosts. Several epidemiological studies have reported transmission heterogeneities for Escherichia coli by cattle, a phenomenon with far-reaching agricultural, medical and public health implications. Focusing on E. coli as a case study, this paper will describe super-spreading and super-shedding by cattle, review the main factors that shape these transmission heterogeneities and examine the interface with human health. Escherichia coli super-shedding and super-spreading by cattle are shaped by microorganism-specific, cattle-specific and environmental factors. Understanding the factors that shape heterogeneities in E. coli dispersion by cattle and the implications for human health represent key components that are critical for targeted infection control initiatives.
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Affiliation(s)
- Richard A Stein
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.,Department of Natural Sciences, LaGuardia Community College, City University of New York, Long Island City, NY 11101, USA
| | - David E Katz
- Department of Internal Medicine, Shaare Zedek Medical Center, Hebrew University School of Medicine, Jerusalem 91031, Israel
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Yoo BB, Liu Y, Juneja V, Huang L, Hwang CA. Effect of environmental stresses on the survival and cytotoxicity of Shiga toxin-producing Escherichia coli†. FOOD QUALITY AND SAFETY 2017. [DOI: 10.1093/fqsafe/fyx010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Saeedi P, Yazdanparast M, Behzadi E, Salmanian AH, Mousavi SL, Nazarian S, Amani J. A review on strategies for decreasing E. coli O157:H7 risk in animals. Microb Pathog 2017; 103:186-195. [PMID: 28062285 DOI: 10.1016/j.micpath.2017.01.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/25/2016] [Accepted: 01/02/2017] [Indexed: 11/17/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a food-borne pathogen that younger children are most prone to this microorganism. Hemolytic Uremic Syndrome (HUS) caused by EHEC, leads to the destruction of red blood cells and kidney failure. The virulence of E.coli O157:H7 is attributed to fimbriae, that facilitate colonization of bacteria within the colon and verotoxins (VT) or Shiga toxins (Stx) that are released into the blood. Although, in most cases, the infection is self-limitedin young children and aged population, it may cause HUS. Therefore, several investigations are performed in order to offer effective therapies and vaccines, which can prevent and treat the infection in appropriate time. As the pathogenesis of this infection is complicated, a multi-targeted strategy is required. Since cattle are the most important reservoir of EHEC and the root of contamination, reducing E. coli O157:H7 at the farm level should decrease the risk of human illness. Several vaccine approaches have been employed with different proper outcomes in animal models, including recombinant proteins (virulence factors such as; Stx1/2, intimin, EspA, fusion proteins of A and B Stx subunits), avirulent ghost cells of EHEC O157:H7, live attenuated bacteria expressing recombinant proteins, recombinant fimbrial proteins. In addition to protein-based vaccines, DNA vaccines have provided proper prevention in the laboratory animal model. This review paper summarizes the previous studies, current status and future perspective of different immunization strategies for eradicating Enterohemorrhagic Escherichia coli O157:H7.
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Affiliation(s)
- Pardis Saeedi
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Maryam Yazdanparast
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Elham Behzadi
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Hatef Salmanian
- Plant Bioproducts Department, Institute of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Seyed Latif Mousavi
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
| | - Shahram Nazarian
- Department of Biology, Faculty of Science, Imam Hossein University, Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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The Locus of Enterocyte Effacement and Associated Virulence Factors of Enterohemorrhagic Escherichia coli. Microbiol Spectr 2016; 2:EHEC-0007-2013. [PMID: 26104209 DOI: 10.1128/microbiolspec.ehec-0007-2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subset of Shiga toxin-producing Escherichia coli strains, termed enterohemorrhagic E. coli (EHEC), is defined in part by the ability to produce attaching and effacing (A/E) lesions on intestinal epithelia. Such lesions are characterized by intimate bacterial attachment to the apical surface of enterocytes, cytoskeletal rearrangements beneath adherent bacteria, and destruction of proximal microvilli. A/E lesion formation requires the locus of enterocyte effacement (LEE), which encodes a Type III secretion system that injects bacterial proteins into host cells. The translocated proteins, termed effectors, subvert a plethora of cellular pathways to the benefit of the pathogen, for example, by recruiting cytoskeletal proteins, disrupting epithelial barrier integrity, and interfering with the induction of inflammation, phagocytosis, and apoptosis. The LEE and selected effectors play pivotal roles in intestinal persistence and virulence of EHEC, and it is becoming clear that effectors may act in redundant, synergistic, and antagonistic ways during infection. Vaccines that target the function of the Type III secretion system limit colonization of reservoir hosts by EHEC and may thus aid control of zoonotic infections. Here we review the features and functions of the LEE-encoded Type III secretion system and associated effectors of E. coli O157:H7 and other Shiga toxin-producing E. coli strains.
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"Preharvest" Food Safety for Escherichia coli O157 and Other Pathogenic Shiga Toxin-Producing Strains. Microbiol Spectr 2016; 2. [PMID: 26104364 DOI: 10.1128/microbiolspec.ehec-0021-2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Preharvest food safety refers to the concept of reducing the rates of contamination of unprocessed foods with food-borne disease pathogens in order to reduce human exposure and disease. This article addresses the search for effective preharvest food safety practices for application to live cattle to reduce both contamination of foods of bovine origin and environmental contamination resulting from cattle. Although this research has resulted in several practices that significantly decrease contamination by Escherichia coli O157, the effects are limited in magnitude and unlikely to affect the incidence of human disease without much wider application and considerably higher efficacy than is presently apparent. Infection of cattle with E. coli O157 is transient and seasonally variable, likely resulting from a complex web of exposures. It is likely that better identification of the true maintenance reservoir of this agent and related Shiga toxin-producing E. coli is required to develop more effective control measures for these important food- and waterborne disease agents.
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Schmidt CE, Shringi S, Besser TE. Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages. PLoS One 2016; 11:e0147270. [PMID: 26824472 PMCID: PMC4732659 DOI: 10.1371/journal.pone.0147270] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 12/25/2015] [Indexed: 12/28/2022] Open
Abstract
Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx) carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1-3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933) and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon). Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli.
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Affiliation(s)
- Carrie E. Schmidt
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail:
| | - Smriti Shringi
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Thomas E. Besser
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
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Livezey KW, Groschel B, Becker MM. Use of the ecf1 gene to detect Shiga toxin-producing Escherichia coli in beef samples. J Food Prot 2015; 78:675-84. [PMID: 25836391 DOI: 10.4315/0362-028x.jfp-14-417] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Escherichia coli O157:H7 and six serovars (O26, O103, O121, O111, O145, and O45) are frequently implicated in severe clinical illness worldwide. Standard testing methods using stx, eae, and O serogroup-specific gene sequences for detecting the top six non-O157 STEC bear the disadvantage that these genes may reside, independently, in different nonpathogenic organisms, leading to false-positive results. The ecf operon has previously been identified in the large enterohemolysin-encoding plasmid of eae-positive Shiga toxin-producing E. coli (STEC). Here, we explored the utility of the ecf operon as a single marker to detect eae-positive STEC from pure broth and primary meat enrichments. Analysis of 501 E. coli isolates demonstrated a strong correlation (99.6%) between the presence of the ecf1 gene and the combined presence of stx, eae, and ehxA genes. Two large studies were carried out to determine the utility of an ecf1 detection assay to detect non-O157 STEC strains in enriched meat samples in comparison to the results using the U. S. Department of Agriculture Food Safety and Inspection Service (FSIS) method that detects stx and eae genes. In ground beef samples (n = 1,065), the top six non-O157 STEC were detected in 4.0% of samples by an ecf1 detection assay and in 5.0% of samples by the stx- and eae-based method. In contrast, in beef samples composed largely of trim (n = 1,097), the top six non-O157 STEC were detected at 1.1% by both methods. Estimation of false-positive rates among the top six non-O157 STEC revealed a lower rate using the ecf1 detection method (0.5%) than using the eae and stx screening method (1.1%). Additionally, the ecf1 detection assay detected STEC strains associated with severe illness that are not included in the FSIS regulatory definition of adulterant STEC.
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Affiliation(s)
- Kristin W Livezey
- Roka Bioscience, Inc., 10398 Pacific Center Court, San Diego, California 92121, USA
| | - Bettina Groschel
- Roka Bioscience, Inc., 10398 Pacific Center Court, San Diego, California 92121, USA
| | - Michael M Becker
- Roka Bioscience, Inc., 10398 Pacific Center Court, San Diego, California 92121, USA.
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Structural and mechanistic roles of novel chemical ligands on the SdiA quorum-sensing transcription regulator. mBio 2015; 6:mBio.02429-14. [PMID: 25827420 PMCID: PMC4453555 DOI: 10.1128/mbio.02429-14] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Bacteria engage in chemical signaling, termed quorum sensing (QS), to mediate intercellular communication, mimicking multicellular organisms. The LuxR family of QS transcription factors regulates gene expression, coordinating population behavior by sensing endogenous acyl homoserine lactones (AHLs). However, some bacteria (such as Escherichia coli) do not produce AHLs. These LuxR orphans sense exogenous AHLs but also regulate transcription in the absence of AHLs. Importantly, this AHL-independent regulatory mechanism is still largely unknown. Here we present several structures of one such orphan LuxR-type protein, SdiA, from enterohemorrhagic E. coli (EHEC), in the presence and absence of AHL. SdiA is actually not in an apo state without AHL but is regulated by a previously unknown endogenous ligand, 1-octanoyl-rac-glycerol (OCL), which is ubiquitously found throughout the tree of life and serves as an energy source, signaling molecule, and substrate for membrane biogenesis. While exogenous AHL renders to SdiA higher stability and DNA binding affinity, OCL may function as a chemical chaperone placeholder that stabilizes SdiA, allowing for basal activity. Structural comparison between SdiA-AHL and SdiA-OCL complexes provides crucial mechanistic insights into the ligand regulation of AHL-dependent and -independent function of LuxR-type proteins. Importantly, in addition to its contribution to basic science, this work has implications for public health, inasmuch as the SdiA signaling system aids the deadly human pathogen EHEC to adapt to a commensal lifestyle in the gastrointestinal (GI) tract of cattle, its main reservoir. These studies open exciting and novel avenues to control shedding of this human pathogen in the environment. IMPORTANCE Quorum sensing refers to bacterial chemical signaling. The QS acyl homoserine lactone (AHL) signals are recognized by LuxR-type receptors that regulate gene transcription. However, some bacteria have orphan LuxR-type receptors and do not produce AHLs, sensing them from other bacteria. We solved three structures of the E. coli SdiA orphan, in the presence and absence of AHL. SdiA with no AHL is not in an apo state but is regulated by a previously unknown endogenous ligand, 1-octanoyl-rac-glycerol (OCL). OCL is ubiquitously found in prokaryotes and eukaryotes and is a phospholipid precursor for membrane biogenesis and a signaling molecule. While AHL renders to SdiA higher stability and DNA-binding affinity, OCL functions as a chemical chaperone placeholder, stabilizing SdiA and allowing for basal activity. Our studies provide crucial mechanistic insights into the ligand regulation of SdiA activity.
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Complete Genome Sequence of SS52, a Strain of Escherichia coli O157:H7 Recovered from Supershedder Cattle. GENOME ANNOUNCEMENTS 2015; 3:3/2/e01569-14. [PMID: 25792068 PMCID: PMC4395050 DOI: 10.1128/genomea.01569-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Shiga toxin-producing Escherichia coli O157:H7 causes foodborne infections, and cattle are the primary reservoir. Some animals, known as supershedders, excrete orders of magnitude more E. coli O157:H7 in the feces than normal. Here, we report the complete genome sequence of the SS52 supershedder strain of E. coli O157:H7.
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Cote R, Katani R, Moreau MR, Kudva IT, Arthur TM, DebRoy C, Mwangi MM, Albert I, Raygoza Garay JA, Li L, Brandl MT, Carter MQ, Kapur V. Comparative analysis of super-shedder strains of Escherichia coli O157:H7 reveals distinctive genomic features and a strongly aggregative adherent phenotype on bovine rectoanal junction squamous epithelial cells. PLoS One 2015; 10:e0116743. [PMID: 25664460 PMCID: PMC4321836 DOI: 10.1371/journal.pone.0116743] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022] Open
Abstract
Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as “super-shedders” (SS), are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces). Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17) revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359), including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE) cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells.
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Affiliation(s)
- Rebecca Cote
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Robab Katani
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew R. Moreau
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Indira T. Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa, United States of America
| | - Terrance M. Arthur
- Roman L. Hruska U.S. Meat Animal Research Center, Agricultural Research Service, U.S. Department of Agriculture, Clay Center, Nebraska, United States of America
| | - Chitrita DebRoy
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- E. coli Reference Center, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michael M. Mwangi
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Istvan Albert
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Juan Antonio Raygoza Garay
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lingling Li
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Maria T. Brandl
- Produce Safety and Microbiology, Research Unit, Agriculture Research Service, U.S. Department of Agriculture, Albany, California, United States of America
| | - Michelle Q. Carter
- Produce Safety and Microbiology, Research Unit, Agriculture Research Service, U.S. Department of Agriculture, Albany, California, United States of America
| | - Vivek Kapur
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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Szu SC, Ahmed A. Clinical Studies of Escherichia coli O157:H7 Conjugate Vaccines in Adults and Young Children. Microbiol Spectr 2014; 2. [PMID: 26104443 DOI: 10.1128/microbiolspec.ehec-0016-2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Indexed: 12/13/2022] Open
Abstract
Pediatric immunization has been the most effective measure to prevent and reduce the burden of infectious diseases in children. The recent inclusion of pneumococcal and meningococcal polysaccharide conjugates in infant immunization further reinforces their importance. Currently there is no human vaccine against enterohemorrhagic Escherichia coli (EHEC) infections. This review focuses on the human EHEC vaccine that has been studied clinically, in particular, the polysaccharide conjugate against E. coli O157. The surface polysaccharide antigen, O-specific polysaccharide, was linked to rEPA, recombinant exotoxin A of Pseudomonas aeruginosa. In adults and children 2 to 5 years old, O157-rEPA conjugates, shown to be safe, induced high levels of antilipopolysaccharide immunoglobulin G with bactericidal activities against E. coli O157, a functional bioassay that mimics the killing of inoculum in vivo. A similar construct using the B subunit of Shiga toxin (Stx) 1 as the carrier protein elicited both bactericidal and toxin-neutralizing antibodies in mice. So far there is no clinical study of Stx-based human vaccine. Passive immunization of Stx-specific antibodies with humanized, chimeric, or human monoclonal antibodies, produced in transgenic mice, showed promising data in animal models and offered high prospects. Demonstrations of their safety and effectiveness in treating hemolytic-uremic syndrome or patients with EHEC infections are under way, and results are much anticipated. For future development, other virulence factors such as the nontoxic Stx B subunit or intimin should be included, either as carrier protein in conjugates or as independent components. The additional antigens from O157 may provide broader coverage to non-O157 Stx-producing E. coli and facilitate both preventive and therapeutic treatment.
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Affiliation(s)
- Shousun Chen Szu
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Amina Ahmed
- Levine Children's Specialty Center-Pediatric Infectious Disease, Carolina Medical Centers, Charlotte, NC 28203
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Gomez SA, Kulow M, Anklam KS, Park D, Kaspar CW, Ivanek R, Döpfer D. Gene markers of generic Escherichia coli associated with colonization and persistence of Escherichia coli O157 in cattle. Prev Vet Med 2014; 117:140-8. [PMID: 25112682 DOI: 10.1016/j.prevetmed.2014.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 07/07/2014] [Accepted: 07/13/2014] [Indexed: 10/25/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157 are important foodborne pathogens whose major reservoir are asymptomatic cattle. There is evidence suggesting that nonpathogenic E. coli and bacteriophages in the gastro-intestinal tract can influence the pathogenicity of EHEC O157. The factors contributing to the onset and persistence of shedding EHEC O157 in cattle are not completely elucidated. This study used Bayesian network analysis to identify genetic markers of generic E. coli associated with shedding of EHEC O157 in cattle from data generated during an oral experimental challenge study in 4 groups of 6 steers inoculated with three different EHEC O157 strains. The quantification of these associations was accomplished using mixed effects logistic regression. The results showed that the concurrent presence of generic E. coli carrying the prophage marker R4-N and the virulence marker stx2 increased the odds of the onset of EHEC O157 shedding. The presence of prophage markers z2322 and X011C increased, while C1.N decreased the odds of shedding EHEC O157 two days later. A significant antagonist interaction effect between the presence of the virulence marker stx2 on the day of shedding EHEC O157 and two days before shedding was also found. In terms of the persistence of EHEC O157 shedding, the presence of prophage marker R4-N (OR=16, and 95% confidence interval (CI): 1.1, 252) was found to increase the odds of stopping EHEC O157 shedding, whereas prophage marker C1.N (OR=0.16, CI: 0.03, 0.7) and the enterohemolysin gene hly (OR=0.03, CI: 0.001, 0.8) were found to significantly decrease the odds of stopping EHEC O157 shedding. In conclusion, the study found that the presence of certain genetic markers in the generic E. coli genome can influence the pathogenicity of EHEC O157.
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Affiliation(s)
- Sonia A Gomez
- Department of Statistics, UW-Madison, 1220 Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA
| | - Megan Kulow
- Department of Medical Sciences, School of Veterinary Medicine, UW-Madison, 2015 Linden Drive, Madison, WI 53706, USA
| | - Kelly S Anklam
- Department of Medical Sciences, School of Veterinary Medicine, UW-Madison, 2015 Linden Drive, Madison, WI 53706, USA
| | - Donjin Park
- Department of Bacteriology, UW-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Charles W Kaspar
- Department of Bacteriology, UW-Madison, 1550 Linden Drive, Madison, WI 53706, USA
| | - Renata Ivanek
- Veterinary Integrative Biosciences, 4458 Texas A&M University, College Station, TX 77843, USA
| | - Dörte Döpfer
- Department of Medical Sciences, School of Veterinary Medicine, UW-Madison, 2015 Linden Drive, Madison, WI 53706, USA.
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Abstract
ABSTRACT
The gastrointestinal tract of mammals is home to a plethora of microbial species that comprise the microbiota. The role of the microbiota in human health is at the forefront of science in recent years, because it is now appreciated that this intricate microbe-host association shapes the host's immune response and physiology. Many diseases are associated with changes in the microbiota, called dysbiosis. Dysbiosis is associated with obesity, metabolic syndromes, inflammatory bowel-disease, inflammatory bowel syndrome, cancer, diabetes, allergies, and autism. The microbiota is largely regarded as a barrier to enteric infections, such as with enterohemorrhagic
Escherichia coli
(EHEC). However, the interactions between pathogens and the microbiota are largely unknown, as is how these interactions influence the outcome of enteric disease. The microbial composition of the gastrointestinal tract shapes the landscape in which EHEC survives within the host. This organism competes for nutrients derived from the host diet, liberates additional resources from dietary and host sources, and produces signaling molecules sensed by EHEC to direct gene expression. To successfully colonize the recto-anal junction of a ruminant, the EHEC reservoir, or the colon of a human, an accidental host, EHEC must alter its physiology to survive within the host digestive tract. In this article, we explore the classes of molecules produced or modified by the microbiota that appear to be instrumental in governing virulence gene expression of EHEC. We also explore how interaction with different microbiotas influences EHEC infectivity and host interaction.
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Plant-derived antimicrobials reduce E. coli O157:H7 virulence factors critical for colonization in cattle gastrointestinal tract in vitro. BIOMED RESEARCH INTERNATIONAL 2014; 2014:212395. [PMID: 25050328 PMCID: PMC4090510 DOI: 10.1155/2014/212395] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/31/2014] [Indexed: 12/30/2022]
Abstract
This study investigated the effect of subinhibitory concentrations (SIC) of five plant-derived antimicrobials (PDAs), namely, trans cinnamaldehyde, eugenol, carvacrol, thymol, and β-resorcylic acid, on E. coli O157:H7 (EHEC) attachment and invasion of cultured bovine colonic (CO) and rectoanal junction (RAJ) epithelial cells. In addition, PDAs' effect on EHEC genes critical for colonization of cattle gastrointestinal tract (CGIT) was determined in bovine rumen fluid (RF) and intestinal contents (BICs). Primary bovine CO and RAJ epithelial cells were established and were separately inoculated with three EHEC strains with or without (control) SIC of each PDA. Following incubation, EHEC that attached and invaded the cells were determined. Furthermore, the expression of EHEC genes critical for colonization in cattle was investigated using real-time, quantitative polymerase chain reaction in RF and BICs. All the PDAs decreased EHEC invasion of CO and RAJ epithelial cells (P < 0.05). The PDAs also downregulated (P < 0.05) the expression of EHEC genes critical for colonization in CGIT. Results suggest that the PDAs could potentially be used to control EHEC colonization in cattle; however follow-up in vivo studies in cattle are warranted.
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Xu Y, Dugat-Bony E, Zaheer R, Selinger L, Barbieri R, Munns K, McAllister TA, Selinger LB. Escherichia coli O157:H7 super-shedder and non-shedder feedlot steers harbour distinct fecal bacterial communities. PLoS One 2014; 9:e98115. [PMID: 24858731 PMCID: PMC4032279 DOI: 10.1371/journal.pone.0098115] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/28/2014] [Indexed: 02/01/2023] Open
Abstract
Escherichia coli O157:H7 is a major foodborne human pathogen causing disease worldwide. Cattle are a major reservoir for this pathogen and those that shed E. coli O157:H7 at >104 CFU/g feces have been termed "super-shedders". A rich microbial community inhabits the mammalian intestinal tract, but it is not known if the structure of this community differs between super-shedder cattle and their non-shedding pen mates. We hypothesized that the super-shedder state is a result of an intestinal dysbiosis of the microbial community and that a "normal" microbiota prevents E. coli O157:H7 from reaching super-shedding levels. To address this question, we applied 454 pyrosequencing of bacterial 16S rRNA genes to characterize fecal bacterial communities from 11 super-shedders and 11 contemporary pen mates negative for E. coli O157:H7. The dataset was analyzed by using five independent clustering methods to minimize potential biases and to increase confidence in the results. Our analyses collectively indicated significant variations in microbiome composition between super-shedding and non-shedding cattle. Super-shedders exhibited higher bacterial richness and diversity than non-shedders. Furthermore, seventy-two operational taxonomic units, mostly belonging to Firmicutes and Bacteroidetes phyla, were identified showing differential abundance between these two groups of cattle. The operational taxonomic unit affiliation provides new insight into bacterial populations that are present in feces arising from super-shedders of E. coli O157:H7.
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Affiliation(s)
- Yong Xu
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Eric Dugat-Bony
- AgroParisTech National Institute for Agricultural Research, Thiverval, Grignon France
| | - Rahat Zaheer
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Lorna Selinger
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Ruth Barbieri
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Krysty Munns
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - Tim A. McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada
| | - L. Brent Selinger
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
- * E-mail:
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Kudva IT, Stasko JA. Bison and bovine rectoanal junctions exhibit similar cellular architecture and Escherichia coli O157 adherence patterns. BMC Vet Res 2013; 9:266. [PMID: 24373611 PMCID: PMC3878412 DOI: 10.1186/1746-6148-9-266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 12/18/2013] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Escherichia coli O157 (E. coli O157) has been isolated from bison retail meat, a fact that is important given that bison meat has been implicated in an E. coli O157-multistate outbreak. In addition, E. coli O157 has also been isolated from bison feces at slaughter and on farms. Cattle are well documented as E. coli O157 reservoirs, and the primary site of E. coli O157 persistence in such reservoirs is the rectoanal junction (RAJ), located at the distal end of the bovine gastrointestinal tract. Since bison and cattle share many genetic similarities manifested as common lineage, susceptibility to infection and the nature of immune responses to infectious agents, we decided to evaluate whether the RAJ of these animals were comparable both in terms of cellular architecture and as sites for adherence of E. coli O157. Specifically, we compared the histo-morphologies of the RAJ and evaluated the E. coli O157 adherence characteristics to the RAJ squamous epithelial (RSE) cells, from these two species. RESULTS We found that the RAJ of both bison and cattle demonstrated similar distribution of epithelial cell markers villin, vimentin, cytokeratin, E-cadherin and N-cadherin. Interestingly, N-cadherin predominated in the stratified squamous epithelium reflecting its proliferative nature. E. coli O157 strains 86-24 SmR and EDL 933 adhered to RSE cells from both animals with similar diffuse and aggregative patterns, respectively. CONCLUSION Our observations further support the fact that bison are likely 'wildlife' reservoirs for E. coli O157, harboring these bacteria in their gastrointestinal tract. Our results also extend the utility of the RSE-cell assay, previously developed to elucidate E. coli O157-cattle RAJ interactions, to studies in bison, which are warranted to determine whether these observations in vitro correlate with those occurring in vivo at the RAJ within the bison gastrointestinal tract.
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Affiliation(s)
- Indira T Kudva
- Food Safety and Enteric Pathogens Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
| | - Judith A Stasko
- Microscopy Services Laboratory, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
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Detection of Escherichia coli O157 by peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) and comparison to a standard culture method. Appl Environ Microbiol 2013; 79:6293-300. [PMID: 23934486 DOI: 10.1128/aem.01009-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Despite the emergence of non-O157 Shiga toxin-producing Escherichia coli (STEC) infections, E. coli serotype O157 is still the most commonly identified STEC in the world. It causes high morbidity and mortality and has been responsible for a number of outbreaks in many parts of the world. Various methods have been developed to detect this particular serotype, but standard bacteriological methods remain the gold standard. Here, we propose a new peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) method for the rapid detection of E. coli O157. Testing on 54 representative strains showed that the PNA probe is highly sensitive and specific to E. coli O157. The method then was optimized for detection in food samples. Ground beef and unpasteurized milk samples were artificially contaminated with E. coli O157 concentrations ranging from 1 × 10(-2) to 1 × 10(2) CFU per 25 g or ml of food. Samples were then preenriched and analyzed by both the traditional bacteriological method (ISO 16654:2001) and PNA-FISH. The PNA-FISH method performed well in both types of food matrices with a detection limit of 1 CFU/25 g or ml of food samples. Tests on 60 food samples have shown a specificity value of 100% (95% confidence interval [CI], 82.83 to 100), a sensitivity of 97.22% (95% CI, 83.79 to 99.85%), and an accuracy of 98.33% (CI 95%, 83.41 to 99.91%). Results indicate that PNA-FISH performed as well as the traditional culture methods and can reduce the diagnosis time to 1 day.
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SdiA aids enterohemorrhagic Escherichia coli carriage by cattle fed a forage or grain diet. Infect Immun 2013; 81:3472-8. [PMID: 23836826 DOI: 10.1128/iai.00702-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) causes hemorrhagic colitis and life-threatening complications. The main reservoirs for EHEC are healthy ruminants. We reported that SdiA senses acyl homoserine lactones (AHLs) in the bovine rumen to activate expression of the glutamate acid resistance (gad) genes priming EHEC's acid resistance before they pass into the acidic abomasum. Conversely, SdiA represses expression of the locus of enterocyte effacement (LEE) genes, whose expression is not required for bacterial survival in the rumen but is necessary for efficient colonization at the rectoanal junction (RAJ) mucosa. Our previous studies show that SdiA-dependent regulation was necessary for efficient EHEC colonization of cattle fed a grain diet. Here, we compared the SdiA role in EHEC colonization of cattle fed a forage hay diet. We detected AHLs in the rumen of cattle fed a hay diet, and these AHLs activated gad gene expression in an SdiA-dependent manner. The rumen fluid and fecal samples from hay-fed cattle were near neutrality, while the same digesta samples from grain-fed animals were acidic. Cattle fed either grain or hay and challenged with EHEC orally carried the bacteria similarly. EHEC was cleared from the rumen within days and from the RAJ mucosa after approximately one month. In competition trials, where animals were challenged with both wild-type and SdiA deletion mutant bacteria, diet did not affect the outcome that the wild-type strain was better able to persist and colonize. However, the wild-type strain had a greater advantage over the SdiA deletion mutant at the RAJ mucosa among cattle fed the grain diet.
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46
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Escherichia coli O157:H7 LPS O-side chains and pO157 are required for killing Caenorhabditis elegans. Biochem Biophys Res Commun 2013; 436:388-93. [DOI: 10.1016/j.bbrc.2013.05.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/27/2013] [Indexed: 01/13/2023]
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Restrictive Streptomycin Resistance Mutations Decrease the Formation of Attaching and Effacing Lesions in Escherichia coli O157:H7 Strains. Antimicrob Agents Chemother 2013; 57:4260-4266. [PMID: 23796920 DOI: 10.1128/aac.00709-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/14/2013] [Indexed: 12/16/2022] Open
Abstract
Streptomycin binds to the bacterial ribosome and disrupts protein synthesis by promoting misreading of mRNA. Restrictive mutations on the ribosomal subunit protein S12 confer a streptomycin resistance (Strr) phenotype and concomitantly increase the accuracy of the decoding process and decrease the rate of translation. Spontaneous Strr mutants of Escherichia coli O157:H7 have been generated for in vivo studies to promote colonization and to provide a selective marker for this pathogen. The locus of enterocyte effacement (LEE) of E. coli O157:H7 encodes a type III secretion system (T3SS), which is required for attaching and effacing to the intestinal epithelium. In this study, we observed decreases in both the expression and secretion levels of the T3SS translocated proteins EspA and EspB in E. coli O157:H7 Strr restrictive mutants, which have K42T or K42I mutations in S12. However, mildly restrictive (K87R) and nonrestrictive (K42R) mutants showed slight or indistinguishable changes in EspA and EspB secretion. Adherence and actin staining assays indicated that restrictive mutations compromised the formation of attaching and effacing lesions in E. coli O157:H7. Therefore, we suggest that E. coli O157:H7 strains selected for Strr should be thoroughly characterized before in vivo and in vitro experiments that assay for LEE-directed phenotypes and that strains carrying nonrestrictive mutations such as K42R make better surrogates of wild-type strains than those carrying restrictive mutations.
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Advances in the development of enterohemorrhagic Escherichia coli vaccines using murine models of infection. Vaccine 2013; 31:3229-35. [PMID: 23707170 DOI: 10.1016/j.vaccine.2013.05.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 01/22/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains are food borne pathogens with importance in public health. EHEC colonizes the large intestine and causes diarrhea, hemorrhagic colitis and in some cases, life-threatening hemolytic-uremic syndrome (HUS) due to the production of Shiga toxins (Stx). The lack of effective clinical treatment, sequelae after infection and mortality rate in humans supports the urgent need of prophylactic approaches, such as development of vaccines. Shedding from cattle, the main EHEC reservoir and considered the principal food contamination source, has prompted the development of licensed vaccines that reduce EHEC colonization in ruminants. Although murine models do not fully recapitulate human infection, they are commonly used to evaluate EHEC vaccines and the immune/protective responses elicited in the host. Mice susceptibility differs depending of the EHEC inoculums; displaying different mortality rates and Stx-mediated renal damage. Therefore, several experimental protocols have being pursued in this model to develop EHEC-specific vaccines. Recent candidate vaccines evaluated include those composed of virulence factors alone or as fused-subunits, DNA-based, attenuated bacteria and bacterial ghosts. In this review, we summarize progress in the design and testing of EHEC vaccines and the use of different strategies for the evaluation of novel EHEC vaccines in the murine model.
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Characterization of Escherichia coli O157:H7 strains isolated from supershedding cattle. Appl Environ Microbiol 2013; 79:4294-303. [PMID: 23645203 DOI: 10.1128/aem.00846-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Previous reports have indicated that a small proportion of cattle shedding high levels of Escherichia coli O157:H7 is the main source for transmission of this organism between animals. Cattle achieving a fecal shedding status of 10(4) CFU of E. coli O157:H7/gram or greater are now referred to as supershedders. The aim of this study was to investigate the contribution of E. coli O157:H7 strain type to supershedding and to determine if supershedding was restricted to a specific set of E. coli O157:H7 strains. Fecal swabs (n = 5,086) were collected from cattle at feedlots or during harvest. Supershedders constituted 2.0% of the bovine population tested. Supershedder isolates were characterized by pulsed-field gel electrophoresis (PFGE), phage typing, lineage-specific polymorphism assay (LSPA), Stx-associated bacteriophage insertion (SBI) site determination, and variant analysis of Shiga toxin, tir, and antiterminator Q genes. Isolates representing 52 unique PFGE patterns, 19 phage types, and 12 SBI clusters were obtained from supershedding cattle, indicating that there is no clustering to E. coli O157:H7 genotypes responsible for supershedding. While being isolated directly from cattle, this strain set tended to have higher frequencies of traits associated with human clinical isolates than previously collected bovine isolates with respect to lineage and tir allele, but not for SBI cluster and Q type. We conclude that no exclusive genotype was identified that was common to all supershedder isolates.
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Jeon SJ, Elzo M, DiLorenzo N, Lamb GC, Jeong KC. Evaluation of animal genetic and physiological factors that affect the prevalence of Escherichia coli O157 in cattle. PLoS One 2013; 8:e55728. [PMID: 23405204 PMCID: PMC3566006 DOI: 10.1371/journal.pone.0055728] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/29/2012] [Indexed: 11/19/2022] Open
Abstract
Controlling the prevalence of Escherichia coli O157 in cattle at the pre-harvest level is critical to reduce outbreaks of this pathogen in humans. Multilayers of factors including the environmental and bacterial factors modulate the colonization and persistence of E. coli O157 in cattle that serve as a reservoir of this pathogen. Here, we report animal factors contributing to the prevalence of E. coli O157 in cattle. We observe the lowest number of E. coli O157 in Brahman breed when compared with other crosses in an Angus-Brahman multibreed herd, and bulls excrete more E. coli O157 than steers in the pens where cattle were housed together. The presence of super-shedders, cattle excreting >10(5) CFU/rectal anal swab, increases the concentration of E. coli O157 in the pens; thereby super-shedders enhance transmission of this pathogen among cattle. Molecular subtyping analysis reveal only one subtype of E. coli O157 in the multibreed herd, indicating the variance in the levels of E. coli O157 in cattle is influenced by animal factors. Furthermore, strain tracking after relocation of the cattle to a commercial feedlot reveals farm-to-farm transmission of E. coli O157, likely via super-shedders. Our results reveal high risk factors in the prevalence of E. coli O157 in cattle whereby animal genetic and physiological factors influence whether this pathogen can persist in cattle at high concentration, providing insights to intervene this pathogen at the pre-harvest level.
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Affiliation(s)
- Soo Jin Jeon
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Mauricio Elzo
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Nicolas DiLorenzo
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
- North Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Marianna, Florida, United States of America
| | - G. Cliff Lamb
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
- North Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Marianna, Florida, United States of America
| | - Kwang Cheol Jeong
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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