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Dahar GY, Wang HW, Rajer FU, Jin P, Xu P, Abro MA, Qureshi AS, Karim A, Miao W. Comparative genomic analysis of Bacillus atrophaeus HAB-5 reveals genes associated with antimicrobial and plant growth-promoting activities. Front Microbiol 2024; 15:1384691. [PMID: 38989016 PMCID: PMC11233526 DOI: 10.3389/fmicb.2024.1384691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 06/07/2024] [Indexed: 07/12/2024] Open
Abstract
Bacillus atrophaeus HAB-5 is a plant growth-promoting rhizobacterium (PGPR) that exhibits several biotechnological traits, such as enhancing plant growth, colonizing the rhizosphere, and engaging in biocontrol activities. In this study, we conducted whole-genome sequencing of B. atrophaeus HAB-5 using the single-molecule real-time (SMRT) sequencing platform by Pacific Biosciences (PacBio; United States), which has a circular chromosome with a total length of 4,083,597 bp and a G + C content of 44.21%. The comparative genomic analysis of B. atrophaeus HAB-5 with other strains, Bacillus amyloliquefaciens DSM7, B. atrophaeus SRCM101359, Bacillus velezensis FZB42, B. velezensis HAB-2, and Bacillus subtilis 168, revealed that these strains share 2,465 CDSs, while 599 CDSs are exclusive to the B. atrophaeus HAB-5 strain. Many gene clusters in the B. atrophaeus HAB-5 genome are associated with the production of antimicrobial lipopeptides and polypeptides. These gene clusters comprise distinct enzymes that encode three NRPs, two Transat-Pks, one terpene, one lanthipeptide, one T3PKS, one Ripp, and one thiopeptide. In addition to the likely IAA-producing genes (trpA, trpB, trpC, trpD, trpE, trpS, ywkB, miaA, and nadE), there are probable genes that produce volatile chemicals (acoA, acoB, acoR, acuB, and acuC). Moreover, HAB-5 contained genes linked to iron transportation (fbpA, fetB, feuC, feuB, feuA, and fecD), sulfur metabolism (cysC, sat, cysK, cysS, and sulP), phosphorus solubilization (ispH, pstA, pstC, pstS, pstB, gltP, and phoH), and nitrogen fixation (nif3-like, gltP, gltX, glnR, glnA, nadR, nirB, nirD, nasD, narl, narH, narJ, and nark). In conclusion, this study provides a comprehensive genomic analysis of B. atrophaeus HAB-5, pinpointing the genes and genomic regions linked to the antimicrobial properties of the strain. These findings advance our knowledge of the genetic basis of the antimicrobial properties of B. atrophaeus and imply that HAB-5 may employ a variety of commercial biopesticides and biofertilizers as a substitute strategy to increase agricultural output and manage a variety of plant diseases.
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Affiliation(s)
- Ghulam Yaseen Dahar
- Key Laboratory of Green Prevention and Control of Tropical Plant Disease and Pests, Ministry of Education, College of Plant Protection, Hainan University Haikou, Haikou, China
| | - Huan Wei Wang
- Key Laboratory of Green Prevention and Control of Tropical Plant Disease and Pests, Ministry of Education, College of Plant Protection, Hainan University Haikou, Haikou, China
| | - Faheem Uddin Rajer
- Department of Plant Pathology, Faculty of Crop Protection, Sindh Agriculture University, Tando Jam, Pakistan
| | - Pengfie Jin
- Key Laboratory of Green Prevention and Control of Tropical Plant Disease and Pests, Ministry of Education, College of Plant Protection, Hainan University Haikou, Haikou, China
| | - Peidong Xu
- Key Laboratory of Green Prevention and Control of Tropical Plant Disease and Pests, Ministry of Education, College of Plant Protection, Hainan University Haikou, Haikou, China
| | - Manzoor Ali Abro
- Department of Plant Pathology, Faculty of Crop Protection, Sindh Agriculture University, Tando Jam, Pakistan
| | - Abdul Sattar Qureshi
- Institute of Biotechnology and Genetic Engineering, University of Sindh, Jamshoro, Pakistan
| | - Asad Karim
- Jamil-Ur-Rahman Center for Genome Research, Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Weiguo Miao
- Key Laboratory of Green Prevention and Control of Tropical Plant Disease and Pests, Ministry of Education, College of Plant Protection, Hainan University Haikou, Haikou, China
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Henriquez T, Guerra S, Nerini M, Purchase D, Marvasi M. The Tomato Variety Affects the Survival of Shigella flexneri 2a in Fruit Pericarp. Pathogens 2024; 13:379. [PMID: 38787231 PMCID: PMC11124042 DOI: 10.3390/pathogens13050379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/08/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
The presence of enteric pathogens in produce can serve as a significant means of transmitting infections to consumers. Notably, tomatoes, as a type of produce, have been implicated in outbreaks caused by various human pathogens, such as Salmonella enterica and pathogenic Escherichia coli. However, the survival characteristics of Shigella spp. in tomatoes have not been thoroughly investigated. In this study, we assess the survival of S. flexneri 2a in two distinct varieties of post-harvested tomatoes. S. flexneri 2a was used to inoculate both regular-sized Vine tomatoes and cherry-type Mini Plum tomatoes. Our findings reveal no significant difference in Shigella survival in the pericarp of both varieties on day 2 post-inoculation. However, a significant disparity emerges on day 6, where all recovered Shigella colonies exclusively belong to the Mini Plum variety, with none associated with the Vine type. When Shigella was inoculated into the locular cavity (deep inoculation), no significant difference between varieties was observed. Additionally, we investigate the potential role of the SRL pathogenicity island (SRL PAI) in the survival and fitness of S. flexneri 2a in post-harvested tomatoes. Our results indicate that while the SRL PAI is not linked to the survival of the strains in tomato, it does impact their fitness. These findings underscore the variability in Shigella strains' survival capabilities depending on the tomato variety, highlighting the importance of understanding Shigella ecology beyond the human host and identifying molecular determinants influencing bacterial survival to mitigate the risk of future outbreaks. The significance of this data on Shigella persistence in fresh vegetables should not be underestimated, as even a small number of Shigella cells can pose a threat to the health of individuals.
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Affiliation(s)
- Tania Henriquez
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy;
| | - Simona Guerra
- Department of Biology, University of Florence, 50019 Florence, Italy; (S.G.); (M.N.)
| | - Marta Nerini
- Department of Biology, University of Florence, 50019 Florence, Italy; (S.G.); (M.N.)
| | - Diane Purchase
- Department of Natural Sciences, Middlesex University London, London NW4 4BT, UK;
| | - Massimiliano Marvasi
- Department of Biology, University of Florence, 50019 Florence, Italy; (S.G.); (M.N.)
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Stenhouse GE, Keddy KH, Bengtsson RJ, Hall N, Smith AM, Thomas J, Iturriza-Gómara M, Baker KS. The genomic epidemiology of shigellosis in South Africa. Nat Commun 2023; 14:7715. [PMID: 38001075 PMCID: PMC10673971 DOI: 10.1038/s41467-023-43345-5] [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: 05/23/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Shigellosis, a leading cause of diarrhoeal mortality and morbidity globally, predominantly affects children under five years of age living in low- and middle-income countries. While whole genome sequence analysis (WGSA) has been effectively used to further our understanding of shigellosis epidemiology, antimicrobial resistance, and transmission, it has been under-utilised in sub-Saharan Africa. In this study, we applied WGSA to large sub-sample of surveillance isolates from South Africa, collected from 2011 to 2015, focussing on Shigella flexneri 2a and Shigella sonnei. We find each serotype is epidemiologically distinct. The four identified S. flexneri 2a clusters having distinct geographical distributions, and antimicrobial resistance (AMR) and virulence profiles, while the four sub-Clades of S. sonnei varied in virulence plasmid retention. Our results support serotype specific lifestyles as a driver for epidemiological differences, show AMR is not required for epidemiological success in S. flexneri, and that the HIV epidemic may have promoted Shigella population expansion.
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Affiliation(s)
- George E Stenhouse
- Clinical Infection, Microbiology, and Immunology, University of Liverpool, Liverpool, UK.
| | | | - Rebecca J Bengtsson
- Clinical Infection, Microbiology, and Immunology, University of Liverpool, Liverpool, UK
| | - Neil Hall
- Earlham Institute, Norwich Research Park, NR4 7UZ, Norwich, UK
| | - Anthony M Smith
- Centre for Enteric Diseases, National Institute for Communicable Diseases (NICD), Division of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
- Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Juno Thomas
- Centre for Enteric Diseases, National Institute for Communicable Diseases (NICD), Division of the National Health Laboratory Service (NHLS), Johannesburg, South Africa
| | - Miren Iturriza-Gómara
- Clinical Infection, Microbiology, and Immunology, University of Liverpool, Liverpool, UK
| | - Kate S Baker
- Clinical Infection, Microbiology, and Immunology, University of Liverpool, Liverpool, UK.
- Department of Genetics, University of Cambridge, CB23EH, Cambridge, UK.
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Genome insights into the plant growth-promoting bacterium Saccharibacillus brassicae ATSA2 T. AMB Express 2023; 13:9. [PMID: 36680648 PMCID: PMC9867790 DOI: 10.1186/s13568-023-01514-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
Endophytes can facilitate the improvement of plant growth and health in agriculturally important crops, yet their genomes and secondary metabolites remain largely unexplored. We previously isolated Saccharibacillus brassicae strain ATSA2T from surface-sterilized seeds of kimchi cabbage and represented a novel species of the genus Saccharibacillus. In this study, we evaluated the plant growth-promoting (PGP) effect of strain ATSA2T in kimchi cabbage, bok choy, and pepper plants grown in soils. We found a significant effect on the shoot and root biomass, and chlorophyll contents following strain ATSA2T treatment. Strain ATSA2T displayed PGP traits such as indole acetic acid (IAA, 62.9 μg/mL) and siderophore production, and phosphate solubilization activity. Furthermore, genome analysis of this strain suggested the presence of gene clusters involved in iron acquisition (fhuABD, afuABC, fbpABC, and fepCDG) and phosphate solubilization (pstABCHS, phoABHLU, and phnCDEP) and other phytohormone biosynthesis genes, including indole-3-acetic acid (trpABCDEFG), in the genome. Interestingly, the secondary metabolites cerecidin, carotenoid, siderophore (staphylobactin), and bacillaene underlying plant growth promotion were found in the whole genome via antiSMASH analysis. Overall, physiological testing and genome analysis data provide comprehensive insights into plant growth-promoting mechanisms, suggesting the relevance of strain ATSA2T in agricultural biotechnology.
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Bacteria in human lumbar discs - subclinical infection or contamination? Metabolomic evidence for colonization, multiplication, and cell-cell cross-talk of bacteria. Spine J 2023; 23:163-177. [PMID: 35569807 DOI: 10.1016/j.spinee.2022.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND CONTEXT The accumulating evidence associating sub-clinical infection with disc degeneration (DD) and the controversy of contamination versus infection mandates a further understanding of the microbial activity in the disc and host-microbiome interaction. PURPOSE To utilize a novel approach of metabolomics to probe the presence of bacterial metabolites involved in colonization, survival, and replication in human lumbar intervertebral discs (LIVD). STUDY DESIGN An observational case-control study. PATIENT SAMPLE Nucleus pulposus from the LIVD of three brain-dead voluntary organ donors (MRI normal and classified as controls) and of three patients undergoing surgery for disc degeneration (DD) (cases) were utilized. METHODS Untargeted metabolite profiling was carried out in six discs (3-controls and 3-cases) after extraction using methanol: acetonitrile: water (2:2:1) solvent system and acquired through HPLC-MS/MS platform using C18 reversed-phase column. From the total IVD metabolome, microbial metabolites were filtered by mapping against HMDB, ChEBI, SigMol, Siderophore database, ecdmb database, and PaMet databases. The biological functions of the metabolites were then studied by MSEA pipeline from Metaboanalyst, and the enrichment ratio, p-value, and Variably Importance Projection scores of the metabolites were calculated. Degeneration responsive changes in the abundance of the microbial metabolites were calculated based on the peak intensities between the control and cases. RESULTS Mass spectrometry identified a total of 17601 and 15003 metabolites, respectively, in the control and degenerated discs. Preliminary mapping of the above metabolites against HMDB indicated the multiple sources, and of these, 64 metabolites were of microbial origin, accounting for 1.6% of the total IVD metabolome. Principle Component Analysis and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA) showed distinct clustered patterns between control and disc degene`ration, indicating a strong variation in concentration, peak, and spectral values of the 64 metabolites between controls and cases. After the exclusion of metabolites that were also associated with humans, drugs, and food, 39 metabolites specific to bacteria were isolated. Nine were primary metabolites related to bacterial growth and survival, and the remaining 30 were secondary metabolites related to different environmental stress response activities. The three significant pathways (p<.001) which were predominant in the bacterial metabolites were autoinducer-2 biosynthesis, peptidoglycan biosynthesis, and chorismate pathway. In addition, a significant fold change of >1.0 was found for nine metabolites which included (S)-14-Methyilhexadecanoic acid related to P. acnes, 9-OxoODE, and 13-OxoODE related to gut flora, vibriobactin - a siderophore, tuberculosinol and iso-tuberculosinol, virulence factors of M. tuberculosis. There was also upregulation of Autoinducer- 2, an important "Quorum sensing molecule" involved in bacterial cross-talk. CONCLUSION We identified several bacterial-specific metabolites participating in bacterial growth, survival, and cross-talk pathways. These were found in both groups but up-regulated in degenerated discs. The presence of Quorum sensing molecules and cell-cell interactions provides firm proof of colonization and growth. These findings indicate that the bacterial presence may not be mere contamination but could be colonization with a possible role in infection-mediated inflammation in DD. CLINICAL SIGNIFICANCE Proof of subclinical infection as an initiator of DD and documentation of exact germ and drug sensitivity will change the way millions of patients with non-specific low back pain (NSLBP) are treated across the world.
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Toro CS, Salazar JC, Montero DA, Ugalde JA, Díaz J, Cádiz LA, Henríquez T, García C, Díaz P, Camponovo R, Hermosilla G, Ulloa MT. Antimicrobial Resistance Dynamics in Chilean Shigella sonnei Strains Within Two Decades: Role of Shigella Resistance Locus Pathogenicity Island and Class 1 and Class 2 Integrons. Front Microbiol 2022; 12:794470. [PMID: 35185820 PMCID: PMC8854971 DOI: 10.3389/fmicb.2021.794470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
Shigellosis is an enteric infectious disease in which antibiotic treatment is effective, shortening the duration of symptoms and reducing the excretion of the pathogen into the environment. Shigella spp., the etiologic agent, are considered emerging pathogens with a high public health impact due to the increase and global spread of multidrug-resistant (MDR) strains. Since Shigella resistance phenotype varies worldwide, we present an overview of the resistance phenotypes and associated genetic determinants present in 349 Chilean S. sonnei strains isolated during the periods 1995–1997, 2002–2004, 2008–2009, and 2010–2013. We detected a great variability in antibiotic susceptibility patterns, finding 300 (86%) MDR strains. Mobile genetic elements (MGE), such as plasmids, integrons, and genomic islands, have been associated with the MDR phenotypes. The Shigella resistance locus pathogenicity island (SRL PAI), which encodes for ampicillin, streptomycin, chloramphenicol, and tetracycline resistance genes, was detected by PCR in 100% of the strains isolated in 2008–2009 but was less frequent in isolates from other periods. The presence or absence of SRL PAI was also differentiated by pulsed-field gel electrophoresis. An atypical class 1 integron which harbors the blaOXA–1-aadA1-IS1 organization was detected as part of SRL PAI. The dfrA14 gene conferring trimethoprim resistance was present in 98.8% of the 2008–2009 isolates, distinguishing them from the SRL-positive strains isolated before that. Thus, it seems an SRL-dfrA14 S. sonnei clone spread during the 2008–2009 period and declined thereafter. Besides these, SRL-negative strains harboring class 2 integrons with or without resistance to nalidixic acid were detected from 2011 onward, suggesting the circulation of another clone. Whole-genome sequencing of selected strains confirmed the results obtained by PCR and phenotypic analysis. It is highlighted that 70.8% of the MDR strains harbored one or more of the MGE evaluated, while 15.2% lacked both SRL PAI and integrons. These results underscore the temporal dynamics of antimicrobial resistance in S. sonnei strains circulating in Chile, mainly determined by the spread of MGE conferring MDR phenotypes. Since shigellosis is endemic in Chile, constant surveillance of antimicrobial resistance phenotypes and their genetic basis is a priority to contribute to public health policies.
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Affiliation(s)
- Cecilia S. Toro
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
- *Correspondence: Cecilia S. Toro,
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - David A. Montero
- Programa Disciplinario de Inmunología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Juan Antonio Ugalde
- C+, Research Center in Technologies for Society, School of Engineering, Universidad del Desarrollo, Santiago, Chile
- Millennium Initiative for Collaborative Research on Bacterial Resistance, Santiago, Chile
| | - Janepsy Díaz
- Departamento de Estudios Científicos, Instituto de Salud Pública de Chile, Santiago, Chile
| | - Leandro A. Cádiz
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Tania Henríquez
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - Camila García
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Patricia Díaz
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | | | - Germán Hermosilla
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - María Teresa Ulloa
- Programa de Microbiología y Micología, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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Mai SNT, Bodhidatta L, Turner P, Wangchuk S, Ha Thanh T, Voong Vinh P, Pham DT, Rabaa MA, Thwaites GE, Thomson NR, Baker S, Chung The H. The evolutionary history of Shigella flexneri serotype 6 in Asia. Microb Genom 2021; 7. [PMID: 34904947 PMCID: PMC8767353 DOI: 10.1099/mgen.0.000736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Shigella flexneri serotype 6 is an understudied cause of diarrhoeal diseases in developing countries, and has been proposed as one of the major targets for vaccine development against shigellosis. Despite being named as S. flexneri, Shigella flexneri serotype 6 is phylogenetically distinct from other S. flexneri serotypes and more closely related to S. boydii. This unique phylogenetic relationship and its low sampling frequency have hampered genomic research on this pathogen. Herein, by utilizing whole genome sequencing (WGS) and analyses of Shigella flexneri serotype 6 collected from epidemiological studies (1987–2013) in four Asian countries, we revealed its population structure and evolutionary history in the region. Phylogenetic analyses supported the delineation of Asian Shigella flexneri serotype 6 into two phylogenetic groups (PG-1 and −2). Notably, temporal phylogenetic approaches showed that extant Asian S. flexneri serotype 6 could be traced back to an inferred common ancestor arising in the 18th century. The dominant lineage PG-1 likely emerged in the 1970s, which coincided with the times to most recent common ancestors (tMRCAs) inferred from other major Southeast Asian S. flexneri serotypes. Similar to other S. flexneri serotypes in the same period in Asia, genomic analyses showed that resistance to first-generation antimicrobials was widespread, while resistance to more recent first-line antimicrobials was rare. These data also showed a number of gene inactivation and gene loss events, particularly on genes related to metabolism and synthesis of cellular appendages, emphasizing the continuing role of reductive evolution in the adaptation of the pathogen to an intracellular lifestyle. Together, our findings reveal insights into the genomic evolution of the understudied Shigella flexneri serotype 6, providing a new piece in the puzzle of Shigella epidemiology and evolution.
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Affiliation(s)
- Si-Nguyen T Mai
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | | | - Paul Turner
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Sonam Wangchuk
- Royal Centre for Disease Control, Ministry of Health, Thimphu, Bhutan
| | - Tuyen Ha Thanh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Duy Thanh Pham
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Maia A Rabaa
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas R Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.,London School of Hygiene and Tropical Medicine, Bloomsbury, London WC1E 7HT, UK
| | - Stephen Baker
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Diseases (CITIID), University of Cambridge, Cambridge, UK
| | - Hao Chung The
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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Abstract
Iron is an essential element for Escherichia, Salmonella, and Shigella species. The acquisition of sufficient amounts of iron is difficult in many environments, including the intestinal tract, where these bacteria usually reside. Members of these genera have multiple iron transport systems to transport both ferrous and ferric iron. These include transporters for free ferrous iron, ferric iron associated with chelators, and heme. The numbers and types of transport systems in any species reflect the diversity of niches that it can inhabit. Many of the iron transport genes are found on mobile genetic elements or pathogenicity islands, and there is evidence of the spread of the genes among different species and pathotypes. This is notable among the pathogenic members of the genera in which iron transport systems acquired by horizontal gene transfer allow the bacteria to overcome host innate defenses that act to restrict the availability of iron to the pathogen. The need for iron is balanced by the need to avoid iron overload since excess iron is toxic to the cell. Genes for iron transport and metabolism are tightly regulated and respond to environmental cues, including iron availability, oxygen, and temperature. Master regulators, the iron sensor Fur and the Fur-regulated small RNA (sRNA) RyhB, coordinate the expression of iron transport and cellular metabolism genes in response to the availability of iron.
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Desvaux M, Dalmasso G, Beyrouthy R, Barnich N, Delmas J, Bonnet R. Pathogenicity Factors of Genomic Islands in Intestinal and Extraintestinal Escherichia coli. Front Microbiol 2020; 11:2065. [PMID: 33101219 PMCID: PMC7545054 DOI: 10.3389/fmicb.2020.02065] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022] Open
Abstract
Escherichia coli is a versatile bacterial species that includes both harmless commensal strains and pathogenic strains found in the gastrointestinal tract in humans and warm-blooded animals. The growing amount of DNA sequence information generated in the era of "genomics" has helped to increase our understanding of the factors and mechanisms involved in the diversification of this bacterial species. The pathogenic side of E. coli that is afforded through horizontal transfers of genes encoding virulence factors enables this bacterium to become a highly diverse and adapted pathogen that is responsible for intestinal or extraintestinal diseases in humans and animals. Many of the accessory genes acquired by horizontal transfers form syntenic blocks and are recognized as genomic islands (GIs). These genomic regions contribute to the rapid evolution, diversification and adaptation of E. coli variants because they are frequently subject to rearrangements, excision and transfer, as well as to further acquisition of additional DNA. Here, we review a subgroup of GIs from E. coli termed pathogenicity islands (PAIs), a concept defined in the late 1980s by Jörg Hacker and colleagues in Werner Goebel's group at the University of Würzburg, Würzburg, Germany. As with other GIs, the PAIs comprise large genomic regions that differ from the rest of the genome by their G + C content, by their typical insertion within transfer RNA genes, and by their harboring of direct repeats (at their ends), integrase determinants, or other mobility loci. The hallmark of PAIs is their contribution to the emergence of virulent bacteria and to the development of intestinal and extraintestinal diseases. This review summarizes the current knowledge on the structure and functional features of PAIs, on PAI-encoded E. coli pathogenicity factors and on the role of PAIs in host-pathogen interactions.
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Affiliation(s)
- Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, Clermont-Ferrand, France
| | - Guillaume Dalmasso
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Racha Beyrouthy
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Nicolas Barnich
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Julien Delmas
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Richard Bonnet
- UMR Inserm 1071, USC-INRAE 2018, M2iSH, Université Clermont Auvergne, Clermont-Ferrand, France
- Laboratoire de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
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Lozano Aguirre LF, Salazar JC, Vásquez JI, García-Angulo VA. Interdependency of regulatory effects of iron and riboflavin in the foodborne pathogen Shigella flexneri determined by integral transcriptomics. PeerJ 2020; 8:e9553. [PMID: 32983629 PMCID: PMC7500357 DOI: 10.7717/peerj.9553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/24/2020] [Indexed: 11/24/2022] Open
Abstract
Shigella flexneri is the causative agent of dysentery. For pathogens, iron is a critical micronutrient as its bioavailability is usually low in bacterial niches. This metal is involved in critical physiological processes mainly as a component of important metabolic molecules involved in redox reactions. Usually bacteria respond to fluctuations in iron availability to regulate iron acquisition and other iron-related functions. Recently the close metabolic feedback between iron and riboflavin, another pivotal biological redox agent, began to draw attention in bacteria. This is a widespread biological phenomenon, partly characterized by the coordination of regulatory responses to iron and riboflavin, probably owed to the involvement of these cofactors in common processes. Nonetheless, no systematic analyses to determine the extent of this regulatory effect have been performed in any species. Here, the transcriptomics responses to iron, riboflavin, iron in the presence of riboflavin and riboflavin in the presence of iron were assessed and compared in S. flexneri. The riboflavin regulon had a 43% overlap with the iron regulon. Notably, the presence of riboflavin highly increased the number of iron-responsive genes. Reciprocally, iron drastically changed the pool of riboflavin-responsive genes. Gene ontology (GO) functional terms enrichment analysis showed that biological processes were distinctively enriched for each subgroup of responsive genes. Among the biological processes regulated by iron and riboflavin were iron uptake, amino acids metabolism and electron transfer for ATP synthesis. Thus, iron and riboflavin highly affect the transcriptomics responses induced by each other in S. flexneri. GO terms analysis suggests that iron and riboflavin coordinately regulate specific physiological functions involving redox metabolism.
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Affiliation(s)
- Luis Fernando Lozano Aguirre
- Unidad de Análisis Bioinformáticos, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
| | - José Ignacio Vásquez
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John, Canada
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Hong JS, Song W, Park HM, Oh JY, Chae JC, Jeong S, Jeong SH. Molecular Characterization of Fecal Extended-Spectrum β-Lactamase- and AmpC β-Lactamase-Producing Escherichia coli From Healthy Companion Animals and Cohabiting Humans in South Korea. Front Microbiol 2020; 11:674. [PMID: 32351490 PMCID: PMC7174606 DOI: 10.3389/fmicb.2020.00674] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/24/2020] [Indexed: 11/13/2022] Open
Abstract
This study aimed to describe the distribution and characterization of fecal extended-spectrum β-lactamase (ESBL)- and AmpC-producing Escherichia coli isolates from healthy companion animals and cohabiting humans. A total of 968 rectal swab samples from 340 participants, including healthy companion animals and cohabiting humans, were collected from 130 households in South Korea from 2018 to 2019. To determine the bacterial profiles of the participants, several experiments were performed as follows: antimicrobial susceptibility testing, PCR and direct sequencing for ESBL/AmpC production, PFGE, MLST, whole genome sequencing and qRT-PCR. A total of 24.9 and 21.5% of the E. coli isolates from healthy companion animals and cohabiting humans were ESBL/AmpC producers, respectively. The blaCTX–M–14 gene was the most prevalent ESC resistance gene in both pets (n = 25/95, 26.3%) and humans (n = 44/126, 34.9%). The blaCMY–2 gene was also largely detected in pets (n = 19, 20.0%). Overall, intrahousehold pet-human sharing of ESBL/AmpC E. coli isolates occurred in 4.8% of households, and the isolates were all CTX-M-14 producers. In particular, ten CMY-2-producing E. coli isolates from seven dogs and three humans in the different households belonged to the same pulsotype. The MIC values of cefoxitin and the transcription level in CMY-2-producing E. coli isolates were proportional to the blaCMY–2 copy number on the chromosome. Our results showed that the clonal spread of fecal ESBL/AmpC-producing E. coli households’ isolates between healthy companion animals and cohabiting humans was rare, but it could happen. In particular, E. coli ST405 isolates carrying multiple blaCMY–2 genes on the chromosome was sporadically spread between companion animals and humans in South Korea.
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Affiliation(s)
- Jun Sung Hong
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, South Korea
| | - Wonkeun Song
- Department of Laboratory Medicine, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Hee-Myung Park
- Department of Veterinary Internal Medicine, College of Veterinary Medicine, Konkuk University, Seoul, South Korea
| | - Jae-Young Oh
- Department of Veterinary Internal Medicine, College of Veterinary Medicine, Konkuk University, Seoul, South Korea
| | - Jong-Chan Chae
- Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan, South Korea
| | - Seri Jeong
- Department of Laboratory Medicine, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Seok Hoon Jeong
- Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, South Korea
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12
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Henríquez T, Salazar JC, Marvasi M, Shah A, Corsini G, Toro CS. SRL pathogenicity island contributes to the metabolism of D-aspartate via an aspartate racemase in Shigella flexneri YSH6000. PLoS One 2020; 15:e0228178. [PMID: 31978153 PMCID: PMC6980539 DOI: 10.1371/journal.pone.0228178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/08/2020] [Indexed: 01/20/2023] Open
Abstract
In recent years, multidrug resistance of Shigella strains associated with genetic elements like pathogenicity islands, have become a public health problem. The Shigella resistance locus pathogenicity island (SRL PAI) of S. flexneri 2a harbors a 16Kbp region that contributes to the multidrug resistance phenotype. However, there is not much information about other functions such as metabolic, physiologic or ecological ones. For that, wild type S. flexneri YSH6000 strain, and its spontaneous SRL PAI mutant, 1363, were used to study the contribution of the island in different growth conditions. Interestingly, when both strains were compared by the Phenotype Microarrays, the ability to metabolize D-aspartic acid as a carbon source was detected in the wild type strain but not in the mutant. When D-aspartate was added to minimal medium with other carbon sources such as mannose or mannitol, the SRL PAI-positive strain was able to metabolize it, while the SRL PAI-negative strain did not. In order to identify the genetic elements responsible for this phenotype, a bioinformatic analysis was performed and two genes belonging to SRL PAI were found: orf8, coding for a putative aspartate racemase, and orf9, coding for a transporter. Thus, it was possible to measure, by an indirect analysis of racemization activity in minimal medium supplemented only with D-aspartate, that YSH6000 strain was able to transform the D-form into L-, while the mutant was impaired to do it. When the orf8-orf9 region from SRL island was transformed into S. flexneri and S. sonnei SRL PAI-negative strains, the phenotype was restored. Although, when single genes were cloned into plasmids, no complementation was observed. Our results strongly suggest that the aspartate racemase and the transporter encoded in the SRL pathogenicity island are important for bacterial survival in environments rich in D-aspartate.
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Affiliation(s)
- Tania Henríquez
- Programa de Microbiología y Micología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Biozentrum, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | | | - Ajit Shah
- Middlesex University London, The Burroughs, London, United Kingdom
| | - Gino Corsini
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Cecilia S. Toro
- Programa de Microbiología y Micología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- * E-mail:
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Ranjbar R, Farahani A. Shigella: Antibiotic-Resistance Mechanisms And New Horizons For Treatment. Infect Drug Resist 2019; 12:3137-3167. [PMID: 31632102 PMCID: PMC6789722 DOI: 10.2147/idr.s219755] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/28/2019] [Indexed: 12/17/2022] Open
Abstract
Shigella spp. are a common cause of diarrheal disease and have remained an important pathogen responsible for increased rates of morbidity and mortality caused by dysentery each year around the globe. Antibiotic treatment of Shigella infections plays an essential role in reducing prevalence and death rates of the disease. However, treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. Drug resistance in Shigella spp. can result from many mechanisms, such as decrease in cellular permeability, extrusion of drugs by active efflux pumps, and overexpression of drug-modifying and -inactivating enzymes or target modification by mutation. Therefore, there is an increasing need for identification and evolution of alternative therapeutic strategies presenting innovative avenues against Shigella infections, as well as paying further attention to this infection. The current review focuses on various antibiotic-resistance mechanisms of Shigella spp. with a particular emphasis on epidemiology and new mechanisms of resistance and their acquisition, and also discusses the status of novel strategies for treatment of Shigella infection and vaccine candidates currently under evaluation in preclinical or clinical phases.
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Affiliation(s)
- Reza Ranjbar
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Abbas Farahani
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Kang H, Wang L, Li Y, Lu Y, Fan W, Bi R, Qian H, Gu B. Dissemination of Multidrug-Resistant Shigella flexneri and Shigella sonnei with Class 1, Class 2, and Atypical Class 1 Integrons in China. Microb Drug Resist 2019; 25:1465-1474. [PMID: 31369341 DOI: 10.1089/mdr.2018.0229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Emergence of multidrug-resistant Shigella, a major causative agent of bacterial dysentery, has generated many concerns not only in China but also worldwide. However, the prevalence of Shigella resistance caused by integron in the nonpopular season of diarrhea is not clear. Materials and Methods: Thirty-one Shigella flexneri and 22 Shigella sonnei samples collected in December 2010 from 10 cities of China were characterized for antimicrobial susceptibility, gene cassettes, widespread of integrons, and pulsed-field gel electrophoresis (PFGE) profile. Results: Multidrug resistance (MDR) was detected in 29 (93.5%) S. flexneri and 20 (90.9%) S. sonnei isolates. Class 1 integrons were detected in 25 (80.6%) S. flexneri and in 13 (59.1%) S. sonnei isolates; class 2 integrons were detected in 26 (83.9%) S. flexneri and in 19 (86.4%) S. sonnei isolates. Interestingly, the atypical class 1 integrons were mostly detected in S. flexneri (45.2%) isolates, whereas in only 1 (4.5%) S. sonnei isolate. DNA sequencing revealed two novel cassette arrays, dfrA5 and aacA4-cmlA, of class 1 integrons in S. flexneri, and dfrA17-aadA5 in S. sonnei isolates. The cassette arrays, dfrA1-sat1-aadA1 of class 2 integron and blaoxa-30-aadA1 of atypical class 1 integron, were also identified. PFGE profiles demonstrated A6 subtype of S. flexneri strains prevalent in Shanghai, Changchun, Jinan, and Changsha; and F6 subtype of S. sonnei prevalent in Jinan, Changchun, and Shanghai. Conclusion: The dissemination of MDR Shigella strains with integrons makes it an increasing public health problem in China. Increased surveillance and the development of adequate prevention strategies are warranted.
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Affiliation(s)
- Haiquan Kang
- Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Lei Wang
- Department of Histology and Embryology, Xuzhou Medical University, Xuzhou, China
| | - Yun Li
- Institute of Clinical Pharmacology, The First Hospital, Peking University, Beijing, China
| | - Yuan Lu
- Institute of Clinical Pharmacology, The First Hospital, Peking University, Beijing, China
| | - Wenting Fan
- Medical Technology School, Xuzhou Medical University, Xuzhou, China
| | - Ruru Bi
- Medical Technology School, Xuzhou Medical University, Xuzhou, China
| | - Huimin Qian
- Department of Acute Infectious Disease Prevention and Control, Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, China
| | - Bing Gu
- Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.,Medical Technology School, Xuzhou Medical University, Xuzhou, China
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15
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Phale PS, Shah BA, Malhotra H. Variability in Assembly of Degradation Operons for Naphthalene and its derivative, Carbaryl, Suggests Mobilization through Horizontal Gene Transfer. Genes (Basel) 2019; 10:genes10080569. [PMID: 31357661 PMCID: PMC6723655 DOI: 10.3390/genes10080569] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/11/2019] [Accepted: 07/11/2019] [Indexed: 01/14/2023] Open
Abstract
In the biosphere, the largest biological laboratory, increased anthropogenic activities have led microbes to evolve and adapt to the changes occurring in the environment. Compounds, specifically xenobiotics, released due to such activities persist in nature and undergo bio-magnification in the food web. Some of these compounds act as potent endocrine disrupters, mutagens or carcinogens, and therefore their removal from the environment is essential. Due to their persistence, microbial communities have evolved to metabolize them partially or completely. Diverse biochemical pathways have evolved or been assembled by exchange of genetic material (horizontal gene transfer) through various mobile genetic elements like conjugative and non-conjugative plasmids, transposons, phages and prophages, genomic islands and integrative conjugative elements. These elements provide an unlimited opportunity for genetic material to be exchanged across various genera, thus accelerating the evolution of a new xenobiotic degrading phenotype. In this article, we illustrate examples of the assembly of metabolic pathways involved in the degradation of naphthalene and its derivative, Carbaryl, which are speculated to have evolved or adapted through the above-mentioned processes.
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Affiliation(s)
- Prashant S Phale
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India.
| | - Bhavik A Shah
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India
| | - Harshit Malhotra
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India
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16
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Kaushik M, Kumar S, Kapoor RK, Gulati P. Integrons and antibiotic resistance genes in water-borne pathogens: threat detection and risk assessment. J Med Microbiol 2019; 68:679-692. [DOI: 10.1099/jmm.0.000972] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Megha Kaushik
- Medical Microbiology and Bioprocess Technology Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001, India
| | - Sanjay Kumar
- Medical Microbiology and Bioprocess Technology Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001, India
| | - Rajeev Kr. Kapoor
- Enzyme Biotechnology Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001, India
| | - Pooja Gulati
- Medical Microbiology and Bioprocess Technology Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, Haryana 124001, India
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Parajuli P, Deimel LP, Verma NK. Genome Analysis of Shigella flexneri Serotype 3b Strain SFL1520 Reveals Significant Horizontal Gene Acquisitions Including a Multidrug Resistance Cassette. Genome Biol Evol 2019; 11:776-785. [PMID: 30715343 PMCID: PMC6424224 DOI: 10.1093/gbe/evz026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2019] [Indexed: 11/23/2022] Open
Abstract
Shigella flexneri is a major etiological agent of shigellosis in developing countries, primarily occurring in children under 5 years of age. We have sequenced, for the first time, the complete genome of S. flexneri serotype 3b (strain SFL1520). We used a hybrid sequencing method--both long-read MinION Flow (Oxford Nanopore Technologies) and short-read MiSeq (Illumina) sequencing to generate a high-quality reference genome. The SFL1520 chromosome was found to be ∼4.58 Mb long, with 4,729 coding sequences. Despite sharing a substantial number of genes with other publicly available S. flexneri genomes (2,803), the SFL1520 strain contains 1,926 accessory genes. The phage-related genes accounted for 8% of the SFL1520 genome, including remnants of the Sf6 bacteriophage with an intact O-acetyltransferase gene specific to serotype 3b. The SFL1520 chromosome was also found to contain a multiple-antibiotic resistance cassette conferring resistance to ampicillin, chloramphenicol, streptomycin, and tetracycline, which was potentially acquired from a plasmid via transposases. The phylogenetic analysis based on core genes showed a high level of similarity of SFL1520 with other S. flexneri serotypes; however, there were marked differences in the accessory genes of SFL1520. In particular, a large number of unique genes were identified in SFL1520 suggesting significant horizontal gene acquisition in a relatively short time period. The major virulence traits of SFL1520 (such as serotype conversion and antimicrobial resistance) were associated with horizontal gene acquisitions highlighting the role of horizontal gene transfer in S. flexneri diversity and evolution.
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Affiliation(s)
- Pawan Parajuli
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Lachlan P Deimel
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Naresh K Verma
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
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18
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Abstract
Inspection of the genomes of bacterial pathogens indicates that their pathogenic potential relies, at least in part, on the activity of different elements that have been acquired by horizontal gene transfer from other (usually unknown) microorganisms. Similarly, in the case of resistance to antibiotics, besides mutation-driven resistance, the incorporation of novel resistance genes is a widespread evolutionary procedure for the acquisition of this phenotype. Current information in the field supports the idea that most (if not all) genes acquired by horizontal gene transfer by bacterial pathogens and contributing to their virulence potential or to antibiotic resistance originate in environmental, not human-pathogenic, microorganisms. Herein I discuss the potential functions that the genes that are dubbed virulence or antibiotic resistance genes may have in their original hosts in nonclinical, natural ecosystems. In addition, I discuss the potential bottlenecks modulating the transfer of virulence and antibiotic resistance determinants and the consequences in terms of speciation of acquiring one or another of both categories of genes. Finally, I propose that exaptation, a process by which a change of function is achieved by a change of habitat and not by changes in the element with the new functionality, is the basis of the evolution of virulence determinants and of antibiotic resistance genes.
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19
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Environmental Adaptability and Quorum Sensing: Iron Uptake Regulation during Biofilm Formation by Paracoccus denitrificans. Appl Environ Microbiol 2018; 84:AEM.00865-18. [PMID: 29776923 DOI: 10.1128/aem.00865-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/07/2018] [Indexed: 11/20/2022] Open
Abstract
Paracoccus denitrificans is a valuable model organism due to its versatile respiration capability and bioenergetic flexibility, both of which are critical to its survival in different environments. Quorum sensing (QS) plays a crucial role in the regulation of many cell functions; however, whether QS systems play a role in P. denitrificans is unknown. In this study, we demonstrated that iron uptake systems in P. denitrificans were directly regulated by a newly identified QS system. Genes coding for TonB-dependent systems, which transport chelated iron, were transcribed at higher levels in the QS-defective mutants. In contrast, genes coding for the Fbp system, which is TonB independent and transports unchelated ferric iron, were downregulated in the mutants. In brief, QS in P. denitrificans triggers a switch in iron uptake from TonB-dependent to TonB-independent transport during biofilm formation as higher concentrations of iron accumulate in the exopolysaccharide (EPS). Switching from TonB-dependent iron uptake systems to TonB-independent systems not only prevents cells from absorbing excess iron but also conserves energy. Our data suggest that iron uptake strategies are directly regulated by QS in Paracoccus denitrificans to support their survival in available ecological niches.IMPORTANCE As iron is an important trace metal for most organisms, its absorption is highly regulated. Fur has been reported as a prevalent regulator of iron acquisition. In addition, there is a relationship between QS and iron acquisition in pathogenic microbes. However, there have been few studies on the iron uptake strategies of nonpathogenic bacteria. In this study, we demonstrated that iron uptake systems in Paracoccus denitrificans PD1222 were regulated by a newly identified PdeR/PdeI QS system during biofilm formation, and we put forward a hypothesis that QS-dependent iron uptake systems benefit the stability of biofilms. This report elaborates the correlation among QS, iron uptake, and biofilm formation and thus contributes to an understanding of the ecological behavior of environmental bacteria.
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20
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Obando S. TA, Babykin MM, Zinchenko VV. A Cluster of Five Genes Essential for the Utilization of Dihydroxamate Xenosiderophores in Synechocystis sp. PCC 6803. Curr Microbiol 2018; 75:1165-1173. [DOI: 10.1007/s00284-018-1505-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/03/2018] [Indexed: 10/16/2022]
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21
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Ma QP, Su L, Liu JW, Yao MX, Yuan GY. Study on the association between drug‑resistance and gene mutations of the active efflux pump acrAB‑tolC gene and its regulatory genes. Mol Med Rep 2018; 17:8228-8236. [PMID: 29693161 PMCID: PMC5983997 DOI: 10.3892/mmr.2018.8916] [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: 07/20/2016] [Accepted: 12/22/2017] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to investigate the correlation between the multi‑drug resistance of Shigella flexneri and the drug‑resistant gene cassette carried by integrons; in the meanwhile, to detect the associations between drug‑resistance and gene mutations of the active efflux pump acrAB‑tolC gene and its regulatory genes, including marOR, acrR and soxS. A total of 158 isolates were isolated from the stool samples of 1,026 children with diarrhoea aged 14 years old between May 2012 and October 2015 in Henan. The K‑B method was applied for the determination of drug resistance of Shigella flexneri, and polymerase chain reaction amplification was used for class 1, 2 and 3 integrase genes. Enzyme digestion and sequence analysis were performed for the variable regions of positive strains. Based on the drug sensitivity assessment, multi‑drug resistant strains that were resistant to five or more antibiotics, and sensitive strains were selected for amplification. Their active efflux pump genes, acrA and acrB, and regulatory genes, marOR, acrR and soxS, were selected for sequencing. The results revealed that 91.1% of the 158 strains were multi‑resistant to ampicillin, chloramphenicol, tetracycline and streptomycin, and 69.6% of the strains were multi‑resistant to sulfamethoxazole/trimethoprim. The resistance to ceftazidime, ciprofloxacin and levofloxacin was <32.9%. All strains (100%) were sensitive to cefoxitin, cefoperazone/sulbactam and imipenem. The rate of the class 1 integron positivity was 91.9% (144/158). Among these class 1 integron‑positive strains, 18 strains exhibited the resistance gene cassette dfrV in the variable region of the strain, four strains exhibited dfrA17‑aadA5 in the variable region and 140 strains exhibited blaOXA‑30‑aadA1 in the variable region. Four strains showed no resistance gene in the variable regions. The rate of class 2 integron positivity was 86.1% (136/158), and all positive strains harboured the dfrA1‑sat1‑aadA resistance gene cassette in the variable region. The class 3 integrase gene was not detected in these strains. The gene sequencing showed the deletion of base CATT in the 36, 37, 38, 39 site in the marOR gene, which is a regulatory gene of the active efflux pump, AcrAB‑TolC. Taken together, the multi‑drug resistance of Shigella flexneri was closely associated with gene mutations of class 1 and 2 integrons and the marOR gene.
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Affiliation(s)
- Quan-Ping Ma
- Department of Clinical Laboratory, Jinan Fourth People's Hospital, Jinan, Shandong 250031, P.R. China
| | - Liang Su
- Department of Clinical Laboratory, Jinan Infectious Disease Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Jing-Wen Liu
- Department of Clinical Laboratory, Jinan Infectious Disease Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Ming-Xiao Yao
- Bacteria Laboratory, Shandong Center for Disease Control and Prevention, Shandong 250014, P.R. China
| | - Guang-Ying Yuan
- Department of Clinical Laboratory, Jinan Infectious Disease Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
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22
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Rosa LT, Bianconi ME, Thomas GH, Kelly DJ. Tripartite ATP-Independent Periplasmic (TRAP) Transporters and Tripartite Tricarboxylate Transporters (TTT): From Uptake to Pathogenicity. Front Cell Infect Microbiol 2018; 8:33. [PMID: 29479520 PMCID: PMC5812351 DOI: 10.3389/fcimb.2018.00033] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 01/25/2018] [Indexed: 11/18/2022] Open
Abstract
The ability to efficiently scavenge nutrients in the host is essential for the viability of any pathogen. All catabolic pathways must begin with the transport of substrate from the environment through the cytoplasmic membrane, a role executed by membrane transporters. Although several classes of cytoplasmic membrane transporters are described, high-affinity uptake of substrates occurs through Solute Binding-Protein (SBP) dependent systems. Three families of SBP dependant transporters are known; the primary ATP-binding cassette (ABC) transporters, and the secondary Tripartite ATP-independent periplasmic (TRAP) transporters and Tripartite Tricarboxylate Transporters (TTT). Far less well understood than the ABC family, the TRAP transporters are found to be abundant among bacteria from marine environments, and the TTT transporters are the most abundant family of proteins in many species of β-proteobacteria. In this review, recent knowledge about these families is covered, with emphasis on their physiological and structural mechanisms, relating to several examples of relevant uptake systems in pathogenicity and colonization, using the SiaPQM sialic acid uptake system from Haemophilus influenzae and the TctCBA citrate uptake system of Salmonella typhimurium as the prototypes for the TRAP and TTT transporters, respectively. High-throughput analysis of SBPs has recently expanded considerably the range of putative substrates known for TRAP transporters, while the repertoire for the TTT family has yet to be fully explored but both types of systems most commonly transport carboxylates. Specialized spectroscopic techniques and site-directed mutagenesis have enriched our knowledge of the way TRAP binding proteins capture their substrate, while structural comparisons show conserved regions for substrate coordination in both families. Genomic and protein sequence analyses show TTT SBP genes are strikingly overrepresented in some bacteria, especially in the β-proteobacteria and some α-proteobacteria. The reasons for this are not clear but might be related to a role for these proteins in signaling rather than transport.
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Affiliation(s)
- Leonardo T Rosa
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Matheus E Bianconi
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Gavin H Thomas
- Department of Biology, University of York, York, United Kingdom
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
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23
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Rajpara N, Nair M, Chowdhury G, Mukhopadhyay AK, Ramamurthy T, Niyogi SK, Bhardwaj AK. Molecular analysis of multidrug resistance in clinical isolates of Shigella spp. from 2001-2010 in Kolkata, India: role of integrons, plasmids, and topoisomerase mutations. Infect Drug Resist 2018; 11:87-102. [PMID: 29391815 PMCID: PMC5769595 DOI: 10.2147/idr.s148726] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To understand the genetic basis of high drug resistance in Shigella, 95 clinical isolates of Shigella spp. (2001-2010) were obtained from the Infectious Diseases Hospital, Kolkata, India. Ninety-three isolates were resistant to three or more antibiotics. Resistance to nalidixic acid, trimethoprim, streptomycin, and co-trimoxazole was most common in this population. Dendrogram analysis showed that S. sonnei strains were more clonally related when compared to the other Shigella species. The role of mobile genetic elements and chromosome-borne resistance factors was analyzed in detail. Integron analysis indicated the preponderance of class 2 and atypical class 1 integrons in that population. Typical class 1 integron was present in only one S. sonnei isolate and harbored trimethoprim resistance-encoding gene dfrV, while atypical class 1 integrons harbored dfrA1-aadA or blaOXA-aadA gene cassettes responsible for resistance to trimethoprim, aminoglycosides, and β-lactams. Class 2 integrons harbored either dfrA1-sat-aadA or dfrA1-sat gene cassettes. Most importantly, a novel gene cassette array InsE-InsO-dfrA1-sat was found in class 2 integron of S. sonnei NK4846. Many of the resistance traits for antibiotics such as trimethoprim, co-trimoxazole, kanamycin, ampicillin, and tetracycline were transferred from parent Shigella isolates to recipient Escherichia coli during conjugation, establishing the role of plasmids in horizontal transfer of resistance genes. Multiple mutations such as S80→I, S83→L, and D87→G/N/Y in quinolone resistance determining regions of topoisomerases from the representative quinolone-resistant isolates could explain the spectrum of minimal inhibitory concentration values for various quinolones. To the best of our knowledge, this is the first comprehensive report that describes the contribution of mobile (plasmids, integrons, and quinolone resistance genes named qnr) and innate genetic elements (mutations in topoisomerases) in determining the resistance phenotype of all the four species of Shigella over a span of ten years.
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Affiliation(s)
- Neha Rajpara
- Department of Human Health and Diseases, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar.,Department of Microbiology and Biotechnology Centre, Maharaja Sayaji Rao University of Baroda, Vadodara, Gujarat
| | - Mrinalini Nair
- Department of Microbiology and Biotechnology Centre, Maharaja Sayaji Rao University of Baroda, Vadodara, Gujarat
| | - Goutam Chowdhury
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata
| | - Asish K Mukhopadhyay
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata
| | - Thandavarayan Ramamurthy
- Center for Human Microbial Ecology, Translational Health Science and Technology Institute, Faridabad, India
| | - Swapan Kumar Niyogi
- Department of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata
| | - Ashima Kushwaha Bhardwaj
- Department of Human Health and Diseases, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar
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24
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Investigating the Relatedness of Enteroinvasive Escherichia coli to Other E. coli and Shigella Isolates by Using Comparative Genomics. Infect Immun 2016; 84:2362-2371. [PMID: 27271741 DOI: 10.1128/iai.00350-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/31/2016] [Indexed: 12/17/2022] Open
Abstract
Enteroinvasive Escherichia coli (EIEC) is a unique pathovar that has a pathogenic mechanism nearly indistinguishable from that of Shigella species. In contrast to isolates of the four Shigella species, which are widespread and can be frequent causes of human illness, EIEC causes far fewer reported illnesses each year. In this study, we analyzed the genome sequences of 20 EIEC isolates, including 14 first described in this study. Phylogenomic analysis of the EIEC genomes demonstrated that 17 of the isolates are present in three distinct lineages that contained only EIEC genomes, compared to reference genomes from each of the E. coli pathovars and Shigella species. Comparative genomic analysis identified genes that were unique to each of the three identified EIEC lineages. While many of the EIEC lineage-specific genes have unknown functions, those with predicted functions included a colicin and putative proteins involved in transcriptional regulation or carbohydrate metabolism. In silico detection of the Shigella virulence plasmid (pINV), which is essential for the invasion of host cells, demonstrated that a form of pINV was present in nearly all EIEC genomes, but the Mxi-Spa-Ipa region of the plasmid that encodes the invasion-associated proteins was absent from several of the EIEC isolates. The comparative genomic findings in this study support the hypothesis that multiple EIEC lineages have evolved independently from multiple distinct lineages of E. coli via the acquisition of the Shigella virulence plasmid and, in some cases, the Shigella pathogenicity islands.
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25
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Njamkepo E, Fawal N, Tran-Dien A, Hawkey J, Strockbine N, Jenkins C, Talukder KA, Bercion R, Kuleshov K, Kolínská R, Russell JE, Kaftyreva L, Accou-Demartin M, Karas A, Vandenberg O, Mather AE, Mason CJ, Page AJ, Ramamurthy T, Bizet C, Gamian A, Carle I, Sow AG, Bouchier C, Wester AL, Lejay-Collin M, Fonkoua MC, Le Hello S, Blaser MJ, Jernberg C, Ruckly C, Mérens A, Page AL, Aslett M, Roggentin P, Fruth A, Denamur E, Venkatesan M, Bercovier H, Bodhidatta L, Chiou CS, Clermont D, Colonna B, Egorova S, Pazhani GP, Ezernitchi AV, Guigon G, Harris SR, Izumiya H, Korzeniowska-Kowal A, Lutyńska A, Gouali M, Grimont F, Langendorf C, Marejková M, Peterson LAM, Perez-Perez G, Ngandjio A, Podkolzin A, Souche E, Makarova M, Shipulin GA, Ye C, Žemličková H, Herpay M, Grimont PAD, Parkhill J, Sansonetti P, Holt KE, Brisse S, Thomson NR, Weill FX. Global phylogeography and evolutionary history of Shigella dysenteriae type 1. Nat Microbiol 2016; 1:16027. [PMID: 27572446 DOI: 10.1038/nmicrobiol.2016.27] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 02/03/2016] [Indexed: 11/09/2022]
Abstract
Together with plague, smallpox and typhus, epidemics of dysentery have been a major scourge of human populations for centuries(1). A previous genomic study concluded that Shigella dysenteriae type 1 (Sd1), the epidemic dysentery bacillus, emerged and spread worldwide after the First World War, with no clear pattern of transmission(2). This is not consistent with the massive cyclic dysentery epidemics reported in Europe during the eighteenth and nineteenth centuries(1,3,4) and the first isolation of Sd1 in Japan in 1897(5). Here, we report a whole-genome analysis of 331 Sd1 isolates from around the world, collected between 1915 and 2011, providing us with unprecedented insight into the historical spread of this pathogen. We show here that Sd1 has existed since at least the eighteenth century and that it swept the globe at the end of the nineteenth century, diversifying into distinct lineages associated with the First World War, Second World War and various conflicts or natural disasters across Africa, Asia and Central America. We also provide a unique historical perspective on the evolution of antibiotic resistance over a 100-year period, beginning decades before the antibiotic era, and identify a prevalent multiple antibiotic-resistant lineage in South Asia that was transmitted in several waves to Africa, where it caused severe outbreaks of disease.
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Affiliation(s)
- Elisabeth Njamkepo
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Nizar Fawal
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Alicia Tran-Dien
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Jane Hawkey
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria 3010, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia.,School of Agriculture and Veterinary Science, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nancy Strockbine
- Centers for Disease Control and Prevention, Escherichia and Shigella Reference Unit, Atlanta, Georgia 30333, USA
| | - Claire Jenkins
- Public Health England, Gastrointestinal Bacteria Reference Unit, Colindale NW9 5HT, UK
| | - Kaisar A Talukder
- icddr,b, Enteric and Food Microbiology Laboratory, Dhaka 1212, Bangladesh
| | - Raymond Bercion
- Institut Pasteur de Bangui, BP 923, Bangui, République Centrafricaine.,Institut Pasteur de Dakar, BP 220, Dakar, Senegal
| | - Konstantin Kuleshov
- Federal Budget Institute of Science, Central Research Institute for Epidemiology, Moscow 111123, Russia
| | - Renáta Kolínská
- Czech National Collection of Type Cultures (CNCTC), National Institute of Public Health, Prague 10, Czech Republic
| | - Julie E Russell
- Public Health England, National Collection of Type Cultures, Porton Down SP4 0JG, UK
| | - Lidia Kaftyreva
- Pasteur Institute of St Petersburg, St Petersburg 197101, Russia
| | - Marie Accou-Demartin
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Andreas Karas
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Olivier Vandenberg
- Department of Microbiology, LHUB-ULB, Brussels University Hospitals Laboratory, 1000 Brussels, Belgium.,Environmental Health Research Centre, Public Health School, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Alison E Mather
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK.,Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Carl J Mason
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand
| | - Andrew J Page
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK
| | | | - Chantal Bizet
- Institut Pasteur, Collection de l'Institut Pasteur (CIP), 75724 Paris Cedex 15, France
| | - Andrzej Gamian
- Polish Collection of Microorganisms, Institute of Immunology and Experimental Therapy, 53-114 Wroclaw, Poland
| | - Isabelle Carle
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | | | | | - Astrid Louise Wester
- Department of Foodborne Infections, Norwegian Institute of Public Health, Nydalen 0403, Oslo, Norway
| | - Monique Lejay-Collin
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | | | - Simon Le Hello
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Martin J Blaser
- Departments of Medicine and Microbiology, New York University Langone Medical Center, New York, New York 10016, USA
| | | | - Corinne Ruckly
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Audrey Mérens
- Biology Department and Infection Control Unit, Bégin Military Hospital, 94160 Saint-Mandé, France
| | | | - Martin Aslett
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK
| | | | - Angelika Fruth
- Divison of Enteropathogenic Bacteria and Legionella, Robert Koch Institut, 38855 Wernigerode, Germany
| | - Erick Denamur
- INSERM, IAME, UMR 1137, Univ. Paris Diderot, IAME, UMR 1137, Sorbonne Paris Cité, 75018 Paris, France
| | - Malabi Venkatesan
- Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA
| | - Hervé Bercovier
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Ladaporn Bodhidatta
- Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok 10400, Thailand
| | - Chien-Shun Chiou
- Center of Research and Diagnostics, Centers for Disease Control, Taichung 40855, Taiwan
| | - Dominique Clermont
- Institut Pasteur, Collection de l'Institut Pasteur (CIP), 75724 Paris Cedex 15, France
| | - Bianca Colonna
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie C Darwin, Sapienza Università di Roma, 00185, Roma, Italy
| | - Svetlana Egorova
- Pasteur Institute of St Petersburg, St Petersburg 197101, Russia
| | - Gururaja P Pazhani
- National Institute of Cholera and Enteric Diseases (NICED), Kolkata, West Bengal 700010, India
| | | | - Ghislaine Guigon
- Institut Pasteur, Genotyping of Pathogens and Public Health Platform, 75724 Paris Cedex 15, France
| | | | - Hidemasa Izumiya
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan
| | | | - Anna Lutyńska
- Department of Sera and Vaccines Evaluation, National Institute of Public Health-National Institute of Hygiene, 00-791 Warsaw, Poland
| | - Malika Gouali
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | - Francine Grimont
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | | | - Monika Marejková
- National Reference Laboratory for E. coli and Shigella, National Institute of Public Health, Prague 10, Czech Republic
| | - Lorea A M Peterson
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba R3E 3R2, Canada
| | - Guillermo Perez-Perez
- Departments of Medicine and Microbiology, New York University Langone Medical Center, New York, New York 10016, USA
| | | | - Alexander Podkolzin
- Federal Budget Institute of Science, Central Research Institute for Epidemiology, Moscow 111123, Russia
| | - Erika Souche
- Institut Pasteur, Bioinformatics platform, 75724 Paris Cedex 15, France
| | - Mariia Makarova
- Pasteur Institute of St Petersburg, St Petersburg 197101, Russia
| | - German A Shipulin
- Federal Budget Institute of Science, Central Research Institute for Epidemiology, Moscow 111123, Russia
| | - Changyun Ye
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Beijing 102206, China
| | - Helena Žemličková
- Czech National Collection of Type Cultures (CNCTC), National Institute of Public Health, Prague 10, Czech Republic.,Department of Clinical Microbiology, Faculty of Medicine and University Hospital, Charles University, 500 05, Hradec Kralove, Czech Republic
| | - Mária Herpay
- Hungarian National Collection of Medical Bacteria, National Center for Epidemiology, H-1097 Budapest, Hungary
| | - Patrick A D Grimont
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France
| | | | - Philippe Sansonetti
- Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, 75724 Paris Cedex 15, France
| | - Kathryn E Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria 3010, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sylvain Brisse
- Institut Pasteur, Genotyping of Pathogens and Public Health Platform, 75724 Paris Cedex 15, France.,Institut Pasteur, Microbial Evolutionary Genomics Unit, 75724 Paris Cedex 15, France.,CNRS, UMR 3525, 75015 Paris, France
| | - Nicholas R Thomson
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK.,London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - François-Xavier Weill
- Institut Pasteur, Unité des Bactéries Pathogènes Entériques, 75724 Paris Cedex 15, France.,Wellcome Trust Sanger Institute, Cambridge CB10 1SA, UK
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26
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The HC, Thanh DP, Holt KE, Thomson NR, Baker S. The genomic signatures of Shigella evolution, adaptation and geographical spread. Nat Rev Microbiol 2016; 14:235-50. [PMID: 26923111 DOI: 10.1038/nrmicro.2016.10] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Shigella spp. are some of the key pathogens responsible for the global burden of diarrhoeal disease. These facultative intracellular bacteria belong to the family Enterobacteriaceae, together with other intestinal pathogens, such as Escherichia coli and Salmonella spp. The genus Shigella comprises four different species, each consisting of several serogroups, all of which show phenotypic similarity, including invasive pathogenicity. DNA sequencing suggests that this similarity results from the convergent evolution of different Shigella spp. founders. Here, we review the evolutionary relationships between Shigella spp. and E . coli, and we highlight how the genomic plasticity of these bacteria and their acquisition of a distinctive virulence plasmid have enabled the development of such highly specialized pathogens. Furthermore, we discuss the insights that genotyping and whole-genome sequencing have provided into the phylogenetics and intercontinental spread of Shigella spp.
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Affiliation(s)
- Hao Chung The
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam
| | - Kathryn E Holt
- Centre for Systems Genomics, University of Melbourne.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Nicholas R Thomson
- Bacterial Genomics, The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.,Centre for Tropical Medicine and Global Health, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, UK
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, University of Oxford, Old Road Campus, Roosevelt Drive, Oxford OX3 7FZ, UK.,Department of Pathogen and Molecular Biology, The London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK
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27
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Wei Y, Murphy ER. Shigella Iron Acquisition Systems and their Regulation. Front Cell Infect Microbiol 2016; 6:18. [PMID: 26904516 PMCID: PMC4746246 DOI: 10.3389/fcimb.2016.00018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/25/2016] [Indexed: 11/28/2022] Open
Abstract
Survival of Shigella within the host is strictly dependent on the ability of the pathogen to acquire essential nutrients, such as iron. As an innate immune defense against invading pathogens, the level of bio-available iron within the human host is maintained at exceeding low levels, by sequestration of the element within heme and other host iron-binding compounds. In response to sequestration mediated iron limitation, Shigella produce multiple iron-uptake systems that each function to facilitate the utilization of a specific host-associated source of nutrient iron. As a mechanism to balance the essential need for iron and the toxicity of the element when in excess, the production of bacterial iron acquisition systems is tightly regulated by a variety of molecular mechanisms. This review summarizes the current state of knowledge on the iron-uptake systems produced by Shigella species, their distribution within the genus, and the molecular mechanisms that regulate their production.
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Affiliation(s)
- Yahan Wei
- Department of Biological Sciences, Ohio University Athens, OH, USA
| | - Erin R Murphy
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University Athens, OH, USA
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28
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Yousuf FA, Rafiq S, Siddiqui R, Khan NA. The role of genomic islands in Escherichia coli K1 interactions with intestinal and kidney epithelial cells. Microb Pathog 2016; 93:145-51. [PMID: 26867478 DOI: 10.1016/j.micpath.2016.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 10/22/2022]
Abstract
The completion of Escherichia coli K1 genome has identified several genomic islands that are present in meningitis-causing E. coli RS218 but absent in the non-pathogenic E. coli MG1655. In this study, the role of various genomic islands in E. coli K1 interactions with intestinal epithelial cells (Caco-2) and kidney epithelial cells (MA104) was determined. Using association assays, invasion assays, and intracellular survival assays, the findings revealed that the genomic island deletion mutants of RS218 related to P fimbriae, S fimbriae, F17-like fimbriae, non-fimbrial adhesins, Hek and hemagglutinin, protein secretion system (T1SS for hemolysin; T2SS; T5SS for antigen 43), Iro system and hmu system), invasins (CNF1, IbeA), toxins (α-hemolysin), K1 capsule biosynthesis, metabolism (d-serine catabolism, dihydroxyacetone, glycerol, and glyoxylate metabolism), prophage genes, showed reduced interactions with both cell types. Next, we determined the role of various genomic islands in E. coli K1 resistance to serum. When exposed to the normal human serum, the viability of the genomic island deletion mutants related to adhesins such as S fimbriae, P fimbriae, F17-like fimbriae, non-fimbrial adhesins, Hek and hemagglutinin, antigen 43 and T5SS for antigen 43, T2SS, and T1SS for hemolysin, Iro system and hmu system, prophage genes, metabolism (sugar metabolism and d-serine catabolism), K1 capsule biosynthesis, and invasins such as CNF1 was affected, suggesting their role in bacteremia. The characterization of these genomic islands should reveal mechanisms of E. coli K1 pathogenicity that could be of value as therapeutic targets.
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Affiliation(s)
| | - Sahar Rafiq
- Department of Biological and Biomedical Sciences, Aga Khan University, Pakistan
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Malaysia.
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29
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Connor TR, Barker CR, Baker KS, Weill FX, Talukder KA, Smith AM, Baker S, Gouali M, Pham Thanh D, Jahan Azmi I, Dias da Silveira W, Semmler T, Wieler LH, Jenkins C, Cravioto A, Faruque SM, Parkhill J, Wook Kim D, Keddy KH, Thomson NR. Species-wide whole genome sequencing reveals historical global spread and recent local persistence in Shigella flexneri. eLife 2015; 4:e07335. [PMID: 26238191 PMCID: PMC4522646 DOI: 10.7554/elife.07335] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/04/2015] [Indexed: 12/15/2022] Open
Abstract
Shigella flexneri is the most common cause of bacterial dysentery in low-income countries. Despite this, S. flexneri remains largely unexplored from a genomic standpoint and is still described using a vocabulary based on serotyping reactions developed over half-a-century ago. Here we combine whole genome sequencing with geographical and temporal data to examine the natural history of the species. Our analysis subdivides S. flexneri into seven phylogenetic groups (PGs); each containing two-or-more serotypes and characterised by distinct virulence gene complement and geographic range. Within the S. flexneri PGs we identify geographically restricted sub-lineages that appear to have persistently colonised regions for many decades to over 100 years. Although we found abundant evidence of antimicrobial resistance (AMR) determinant acquisition, our dataset shows no evidence of subsequent intercontinental spread of antimicrobial resistant strains. The pattern of colonisation and AMR gene acquisition suggest that S. flexneri has a distinct life-cycle involving local persistence.
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Affiliation(s)
- Thomas R Connor
- Cardiff School of Biosciences, Cardiff, United Kingdom
- Pathogen Genomics, Wellcome Trust Sanger Centre, Cambridge, United Kingdom
| | | | - Kate S Baker
- Pathogen Genomics, Wellcome Trust Sanger Centre, Cambridge, United Kingdom
| | | | - Kaisar Ali Talukder
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Anthony M Smith
- Centre for Enteric Diseases, National Institute for Communicable Diseases and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Malika Gouali
- Unité des Bactéries Pathogènes Entériques, Institut Pasteur, Paris, France
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ishrat Jahan Azmi
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Wanderley Dias da Silveira
- Department of Genetics, Evolution, and Bioagents, Institute of Biology, University of Campinas, São Paulo, Brazil
| | - Torsten Semmler
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie University, Berlin, Germany
- Robert Koch Institute, Berlin, Germany
| | - Lothar H Wieler
- Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie University, Berlin, Germany
- Robert Koch Institute, Berlin, Germany
| | - Claire Jenkins
- Gastrointestinal Bacteria Reference Unit, Public Health England, London, United Kingdom
| | | | - Shah M Faruque
- Centre for Food and Water Borne Diseases, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Julian Parkhill
- Pathogen Genomics, Wellcome Trust Sanger Centre, Cambridge, United Kingdom
| | - Dong Wook Kim
- Department of Pharmacy, School of Pharmacy, Hanyang University, Ansan, Republic of Korea
| | - Karen H Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nicholas R Thomson
- Pathogen Genomics, Wellcome Trust Sanger Centre, Cambridge, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
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30
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Chung The H, Karkey A, Pham Thanh D, Boinett CJ, Cain AK, Ellington M, Baker KS, Dongol S, Thompson C, Harris SR, Jombart T, Le Thi Phuong T, Tran Do Hoang N, Ha Thanh T, Shretha S, Joshi S, Basnyat B, Thwaites G, Thomson NR, Rabaa MA, Baker S. A high-resolution genomic analysis of multidrug-resistant hospital outbreaks of Klebsiella pneumoniae. EMBO Mol Med 2015; 7:227-39. [PMID: 25712531 PMCID: PMC4364942 DOI: 10.15252/emmm.201404767] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/19/2015] [Accepted: 01/20/2015] [Indexed: 12/13/2022] Open
Abstract
Multidrug-resistant (MDR) Klebsiella pneumoniae has become a leading cause of nosocomial infections worldwide. Despite its prominence, little is known about the genetic diversity of K. pneumoniae in resource-poor hospital settings. Through whole-genome sequencing (WGS), we reconstructed an outbreak of MDR K. pneumoniae occurring on high-dependency wards in a hospital in Kathmandu during 2012 with a case-fatality rate of 75%. The WGS analysis permitted the identification of two MDR K. pneumoniae lineages causing distinct outbreaks within the complex endemic K. pneumoniae. Using phylogenetic reconstruction and lineage-specific PCR, our data predicted a scenario in which K. pneumoniae, circulating for 6 months before the outbreak, underwent a series of ward-specific clonal expansions after the acquisition of genes facilitating virulence and MDR. We suggest that the early detection of a specific NDM-1 containing lineage in 2011 would have alerted the high-dependency ward staff to intervene. We argue that some form of real-time genetic characterisation, alongside clade-specific PCR during an outbreak, should be factored into future healthcare infection control practices in both high- and low-income settings.
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Affiliation(s)
- Hao Chung The
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Abhilasha Karkey
- Patan Academy of Health Sciences, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - Amy K Cain
- The Wellcome Trust Sanger Institute, Hinxton Cambridge, UK
| | - Matthew Ellington
- The Wellcome Trust Sanger Institute, Hinxton Cambridge, UK Addenbrooke's Hospital, Cambridge, UK
| | - Kate S Baker
- The Wellcome Trust Sanger Institute, Hinxton Cambridge, UK
| | - Sabina Dongol
- Patan Academy of Health Sciences, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Corinne Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Simon R Harris
- The Wellcome Trust Sanger Institute, Hinxton Cambridge, UK
| | - Thibaut Jombart
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, UK
| | - Tu Le Thi Phuong
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nhu Tran Do Hoang
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Shrijana Shretha
- Patan Academy of Health Sciences, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Suchita Joshi
- Patan Academy of Health Sciences, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Buddha Basnyat
- Patan Academy of Health Sciences, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Guy Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Nicholas R Thomson
- The Wellcome Trust Sanger Institute, Hinxton Cambridge, UK The London School of Hygiene and Tropical Medicine, London, UK
| | - Maia A Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, UK
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK The London School of Hygiene and Tropical Medicine, London, UK
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Rohmer L, Jacobs MA, Brittnacher MJ, Fong C, Hayden HS, Hocquet D, Weiss EJ, Radey M, Germani Y, Talukder KA, Hager AJ, Kemner JM, Sims-Day EH, Matamouros S, Hager KR, Miller SI. Genomic analysis of the emergence of 20th century epidemic dysentery. BMC Genomics 2014; 15:355. [PMID: 24886041 PMCID: PMC4038718 DOI: 10.1186/1471-2164-15-355] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 04/15/2014] [Indexed: 12/02/2022] Open
Abstract
Background Shigella dysenteriae type 1 (Sd1) causes recurrent epidemics of dysentery associated with high mortality in many regions of the world. Sd1 infects humans at very low infectious doses (10 CFU), and treatment is complicated by the rapid emergence of antibiotic resistant Sd1 strains. Sd1 is only detected in the context of human infections, and the circumstances under which epidemics emerge and regress remain unknown. Results Phylogenomic analyses of 56 isolates collected worldwide over the past 60 years indicate that the Sd1 clone responsible for the recent pandemics emerged at the turn of the 20th century, and that the two world wars likely played a pivotal role for its dissemination. Several lineages remain ubiquitous and their phylogeny indicates several recent intercontinental transfers. Our comparative genomics analysis reveals that isolates responsible for separate outbreaks, though closely related to one another, have independently accumulated antibiotic resistance genes, suggesting that there is little or no selection to retain these genes in-between outbreaks. The genomes appear to be subjected to genetic drift that affects a number of functions currently used by diagnostic tools to identify Sd1, which could lead to the potential failure of such tools. Conclusions Taken together, the Sd1 population structure and pattern of evolution suggest a recent emergence and a possible human carrier state that could play an important role in the epidemic pattern of infections of this human-specific pathogen. This analysis highlights the important role of whole-genome sequencing in studying pathogens for which epidemiological or laboratory investigations are particularly challenging. Electronic supplementary material The online version of this article (doi: 10.1186/1471-2164-15-355) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laurence Rohmer
- Department of Microbiology, University of Washington, Seattle, WA, USA.
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Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 831] [Impact Index Per Article: 75.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
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Abstract
The proliferative capability of many invasive pathogens is limited by the bioavailability of iron. Pathogens have thus developed strategies to obtain iron from their host organisms. In turn, host defense strategies have evolved to sequester iron from invasive pathogens. This review explores the mechanisms employed by bacterial pathogens to gain access to host iron sources, the role of iron in bacterial virulence, and iron-related genes required for the establishment or maintenance of infection. Host defenses to limit iron availability for bacterial growth during the acute-phase response and the consequences of iron overload conditions on susceptibility to bacterial infection are also examined. The evidence summarized herein demonstrates the importance of iron bioavailability in influencing the risk of infection and the ability of the host to clear the pathogen.
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The IncF plasmid pRSB225 isolated from a municipal wastewater treatment plant's on-site preflooder combining antibiotic resistance and putative virulence functions is highly related to virulence plasmids identified in pathogenic E. coli isolates. Plasmid 2012; 69:127-37. [PMID: 23212116 DOI: 10.1016/j.plasmid.2012.11.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/12/2012] [Accepted: 11/18/2012] [Indexed: 11/22/2022]
Abstract
The IncF antibiotic resistance and virulence plasmid pRSB225, isolated from an unknown bacterium released with the purified wastewater from a municipal sewage treatment plant into the environment has been analysed at the genomic level by pyrosequencing. The 164,550bp plasmid comprises 210 coding sequences (cds). It is composed of three replicons (RepFIA, RepFIB, and RepFII) and encodes further plasmid-specific functions for stable maintenance and inheritance and conjugative plasmid transfer. The plasmid is self-transmissible and shows a narrow host range limited to the family Enterobacteriaceae. The accessory modules of the plasmid mainly comprise genes conferring resistance to ampicillin (bla(TEM-1b)), chloramphenicol (catA1), erythromycin (mphA), kanamycin and neomycin (aphA1), streptomycin (strAB), sulphonamides (sul2), tetracycline (tetA(B)) and trimethoprim (dfrA14), as well as mercuric ions (mer genes). In addition, putative virulence-associated genes coding for iron uptake (iutA/iucABCD, sitABCD, and a putative high-affinity Fe²⁺ uptake system) and for a toxin/antitoxin system (vagCD) were identified on the plasmid. All antibiotic and heavy metal resistance genes are located either on class 1 (Tn10-remnant, Tn4352B) and class 2 transposons (Tn2-remnant, Tn21, Tn402-remnant) or a class 1 integron, whereas almost all putative virulence genes are associated with IS elements (IS1, IS26), indicating that transposition and/or recombination events were responsible for acquisition of the accessory pRSB225 modules. Particular modules of plasmid pRSB225 are related to corresponding segments of different virulence plasmids harboured by pathogenic Escherichia coli strains. Moreover, pRSB225 modules were also detected in entero-aggregative-haemorrhagic E. coli (EAHEC) draft genome sequences suggesting that IncF plasmids related to pRSB225 mediated gene transfer into pathogenic E. coli derivatives.
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Abstract
The analysis of the genomes of bacterial pathogens indicates that they have acquired their pathogenic capability by incorporating different genetic elements through horizontal gene transfer. The ancestors of virulent bacteria, as well as the origin of virulence determinants, lay most likely in the environmental microbiota. Studying the role that these determinants may have in non-clinical ecosystems is thus of value for understanding in detail the evolution and the ecology of bacterial pathogens. In this article, I propose that classical virulence determinants might be relevant for basic metabolic processes (for instance iron-uptake systems) or in modulating prey/predator relationships (toxins) in natural, non-infective ecosystems. The different role that horizontal gene transfer and mutation may have in the evolution of bacterial pathogens either for their speciation or in short-sighted evolution processes is also discussed.
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Affiliation(s)
- José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Darwin 3, Cantoblanco, 28049-Madrid, Spain.
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Prosseda G, Di Martino ML, Campilongo R, Fioravanti R, Micheli G, Casalino M, Colonna B. Shedding of genes that interfere with the pathogenic lifestyle: the Shigella model. Res Microbiol 2012; 163:399-406. [DOI: 10.1016/j.resmic.2012.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 07/08/2012] [Indexed: 12/31/2022]
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Identification and characterization of Cronobacter iron acquisition systems. Appl Environ Microbiol 2012; 78:6035-50. [PMID: 22706064 DOI: 10.1128/aem.01457-12] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cronobacter spp. are emerging pathogens that cause severe infantile meningitis, septicemia, or necrotizing enterocolitis. Contaminated powdered infant formula has been implicated as the source of Cronobacter spp. in most cases, but questions still remain regarding the natural habitat and virulence potential for each strain. The iron acquisition systems in 231 Cronobacter strains isolated from different sources were identified and characterized. All Cronobacter spp. have both the Feo and Efe systems for acquisition of ferrous iron, and all plasmid-harboring strains (98%) have the aerobactin-like siderophore, cronobactin, for transport of ferric iron. All Cronobacter spp. have the genes encoding an enterobactin-like siderophore, although it was not functional under the conditions tested. Furthermore, all Cronobacter spp. have genes encoding five receptors for heterologous siderophores. A ferric dicitrate transport system (fec system) is encoded specifically by a subset of Cronobacter sakazakii and C. malonaticus strains, of which a high percentage were isolated from clinical samples. Phylogenetic analysis confirmed that the fec system is most closely related to orthologous genes present in human-pathogenic bacterial strains. Moreover, all strains of C. dublinensis and C. muytjensii encode two receptors, FcuA and Fct, for heterologous siderophores produced by plant pathogens. Identification of putative Fur boxes and expression of the genes under iron-depleted conditions revealed which genes and operons are components of the Fur regulon. Taken together, these results support the proposition that C. sakazakii and C. malonaticus may be more associated with the human host and C. dublinensis and C. muytjensii with plants.
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Wei YX, Zhang ZY, Liu C, Malakar PK, Guo XK. Safety assessment of Bifidobacterium longum JDM301 based on complete genome sequences. World J Gastroenterol 2012; 18:479-88. [PMID: 22346255 PMCID: PMC3270512 DOI: 10.3748/wjg.v18.i5.479] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/31/2011] [Accepted: 08/07/2011] [Indexed: 02/06/2023] Open
Abstract
AIM To assess the safety of Bifidobacterium longum (B. longum) JDM301 based on complete genome sequences. METHODS The complete genome sequences of JDM301 were determined using the GS 20 system. Putative virulence factors, putative antibiotic resistance genes and genes encoding enzymes responsible for harmful metabolites were identified by blast with virulence factors database, antibiotic resistance genes database and genes associated with harmful metabolites in previous reports. Minimum inhibitory concentration of 16 common antimicrobial agents was evaluated by E-test. RESULTS JDM301 was shown to contain 36 genes associated with antibiotic resistance, 5 enzymes related to harmful metabolites and 162 nonspecific virulence factors mainly associated with transcriptional regulation, adhesion, sugar and amino acid transport. B. longum JDM301 was intrinsically resistant to ciprofloxacin, amikacin, gentamicin and streptomycin and susceptible to vancomycin, amoxicillin, cephalothin, chloramphenicol, erythromycin, ampicillin, cefotaxime, rifampicin, imipenem and trimethoprim-sulphamethoxazol. JDM301 was moderately resistant to bacitracin, while an earlier study showed that bifidobacteria were susceptible to this antibiotic. A tetracycline resistance gene with the risk of transfer was found in JDM301, which needs to be experimentally validated. CONCLUSION The safety assessment of JDM301 using information derived from complete bacterial genome will contribute to a wider and deeper insight into the safety of probiotic bacteria.
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Zhang T, Zhang XX, Ye L. Plasmid metagenome reveals high levels of antibiotic resistance genes and mobile genetic elements in activated sludge. PLoS One 2011; 6:e26041. [PMID: 22016806 PMCID: PMC3189950 DOI: 10.1371/journal.pone.0026041] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 09/16/2011] [Indexed: 11/19/2022] Open
Abstract
The overuse or misuse of antibiotics has accelerated antibiotic resistance, creating a major challenge for the public health in the world. Sewage treatment plants (STPs) are considered as important reservoirs for antibiotic resistance genes (ARGs) and activated sludge characterized with high microbial density and diversity facilitates ARG horizontal gene transfer (HGT) via mobile genetic elements (MGEs). However, little is known regarding the pool of ARGs and MGEs in sludge microbiome. In this study, the transposon aided capture (TRACA) system was employed to isolate novel plasmids from activated sludge of one STP in Hong Kong, China. We also used Illumina Hiseq 2000 high-throughput sequencing and metagenomics analysis to investigate the plasmid metagenome. Two novel plasmids were acquired from the sludge microbiome by using TRACA system and one novel plasmid was identified through metagenomics analysis. Our results revealed high levels of various ARGs as well as MGEs for HGT, including integrons, transposons and plasmids. The application of the TRACA system to isolate novel plasmids from the environmental metagenome, coupled with subsequent high-throughput sequencing and metagenomic analysis, highlighted the prevalence of ARGs and MGEs in microbial community of STPs.
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Affiliation(s)
- Tong Zhang
- Environmental Biotechnology Lab, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China.
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Wyckoff EE, Payne SM. The Vibrio cholerae VctPDGC system transports catechol siderophores and a siderophore-free iron ligand. Mol Microbiol 2011; 81:1446-58. [PMID: 21790806 DOI: 10.1111/j.1365-2958.2011.07775.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vibrio cholerae, the causative agent of cholera, has an absolute requirement for iron. It transports the catechol siderophores vibriobactin, which it synthesizes and secretes, and enterobactin. These siderophores are transported across the inner membrane by one of two periplasmic binding protein-dependent ABC transporters, VctPDGC or ViuPDGC. We show here that one of these inner membrane transport systems, VctPDGC, also promotes iron acquisition in the absence of siderophores. Plasmids carrying the vctPDGC genes stimulated growth in both rich and minimal media of a Shigella flexneri mutant that produces no siderophores. vctPDGC also stimulated the growth of an Escherichia coli enterobactin biosynthetic mutant in low iron medium, and this effect did not require feoB, tonB or aroB. A tyrosine to phenylalanine substitution in the periplasmic binding protein VctP did not alter enterobactin transport, but eliminated growth stimulation in the absence of a siderophore. These data suggest that the VctPDGC system has the capacity to transport both catechol siderophores and a siderophore-free iron ligand. We also show that VctPDGC is the previously unidentified siderophore-independent iron transporter in V. cholerae, and this appears to complete the list of iron transport systems in V. cholerae.
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Affiliation(s)
- Elizabeth E Wyckoff
- Section of Molecular Genetics and Microbiology and Institute of Cellular and Molecular Biology, The University of Texas, Austin, TX 78712, USA.
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41
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Abstract
Antibiotic resistance in Gram-negative bacteria is often due to the acquisition of resistance genes from a shared pool. In multiresistant isolates these genes, together with associated mobile elements, may be found in complex conglomerations on plasmids or on the chromosome. Analysis of available sequences reveals that these multiresistance regions (MRR) are modular, mosaic structures composed of different combinations of components from a limited set arranged in a limited number of ways. Components common to different MRR provide targets for homologous recombination, allowing these regions to evolve by combinatorial evolution, but our understanding of this process is far from complete. Advances in technology are leading to increasing amounts of sequence data, but currently available automated annotation methods usually focus on identifying ORFs and predicting protein function by homology. In MRR, where the genes are often well characterized, the challenge is to identify precisely which genes are present and to define the boundaries of complete and fragmented mobile elements. This review aims to summarize the types of mobile elements involved in multiresistance in Gram-negative bacteria and their associations with particular resistance genes, to describe common components of MRR and to illustrate methods for detailed analysis of these regions.
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Affiliation(s)
- Sally R Partridge
- Centre for Infectious Diseases and Microbiology, The University of Sydney, Westmead Hospital, Sydney, NSW 2145, Australia.
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Napolitano MG, Almagro-Moreno S, Boyd EF. Dichotomy in the evolution of pathogenicity island and bacteriophage encoded integrases from pathogenic Escherichia coli strains. INFECTION GENETICS AND EVOLUTION 2011; 11:423-36. [DOI: 10.1016/j.meegid.2010.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 11/29/2022]
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Bielaszewska M, Middendorf B, Tarr PI, Zhang W, Prager R, Aldick T, Dobrindt U, Karch H, Mellmann A. Chromosomal instability in enterohaemorrhagic Escherichia coli O157:H7: impact on adherence, tellurite resistance and colony phenotype. Mol Microbiol 2011; 79:1024-44. [PMID: 21299654 PMCID: PMC3064760 DOI: 10.1111/j.1365-2958.2010.07499.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tellurite (Tel) resistant enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is a global pathogen. In strain EDL933 Tel resistance (TelR) is encoded by duplicate ter cluster in O islands (OI) 43 and 48, which also harbour iha, encoding the adhesin and siderophore receptor Iha. We identified five EHEC O157:H7 strains that differentiate into large (L) colonies and small (S) colonies with high and low Tel minimal inhibitory concentrations (MICs) respectively. S colonies (Tel-MICs ≤ 4 µg ml−1) sustained large internal deletions within the TelR OIs via homologous recombination between IS elements and lost ter and iha. Moreover, complete excision of the islands occurred by site-specific recombination between flanking direct repeats. Complete excision of OI 43 and OI 48 occurred in 1.81 × 10−3 and 1.97 × 10−4 cells in culture, respectively; internal deletion of OI 48 was more frequent (9.7 × 10−1 cells). Under iron limitation that promotes iha transcription, iha-negative derivatives adhered less well to human intestinal epithelial cells and grew slower than did their iha-positive counterparts. Experiments utilizing iha deletion and complementation mutants identified Iha as the major factor responsible for these phenotypic differences. Spontaneous deletions affecting TelR OIs contribute to EHEC O157 genome plasticity and might impair virulence and/or fitness.
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Affiliation(s)
- Martina Bielaszewska
- Institute of Hygiene and the National Consulting Laboratory on Haemolytic Uraemic Syndrome, University of Münster, Robert Koch Str. 41, 48149 Münster, Germany.
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Zhang J, van Aartsen JJ, Jiang X, Shao Y, Tai C, He X, Tan Z, Deng Z, Jia S, Rajakumar K, Ou HY. Expansion of the known Klebsiella pneumoniae species gene pool by characterization of novel alien DNA islands integrated into tmRNA gene sites. J Microbiol Methods 2010; 84:283-9. [PMID: 21182879 DOI: 10.1016/j.mimet.2010.12.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 12/06/2010] [Accepted: 12/12/2010] [Indexed: 10/18/2022]
Abstract
Klebsiella pneumoniae is an important bacterial pathogen of man that is commonly associated with opportunistic and hospital-associated infections. Increasing levels of multiple-antibiotic resistance associated with this species pose a major emerging clinical problem. This organism also occurs naturally in other diverse environments, including the soil. Consistent with its varied lifestyle and membership of the Enterobacteriaceae family, K. pneumoniae genomes exhibit highly plastic architecture comprising a core genome backbone interspersed with numerous and varied alien genomic islands. In this study the size of the presently known K. pneumoniae pan-genome gene pool was estimated through analysis of complete sequences of three chromosomes and 31 plasmids belonging to K. pneumoniae strains. In addition, using a PCR-based strategy the genomic content of eight tRNA/tmRNA gene sites that serve as DNA insertion hotspots were investigated in 28 diverse environmental and clinical strains of K. pneumoniae. Sequencing and characterization of five newly identified horizontally-acquired tmRNA-associated islands further expanded the archived K. pneumoniae gene pool to a total of 7648 unique gene members. Large-scale investigation of the content of tRNA/tmRNA hotspots will be useful to identify and/or survey accessory sequences dispersed amongst hundreds to thousands of members of many key bacterial species.
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Affiliation(s)
- Jie Zhang
- Key Laboratory of Industrial Microbiology, Ministry of Education, Tianjin University of Science and Technology, Tianjin, PR China
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Atypical class 1 integron coexists with class 1 and class 2 integrons in multi-drug resistant Shigella flexneri isolates from China. Curr Microbiol 2010; 62:802-6. [PMID: 20976456 DOI: 10.1007/s00284-010-9790-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 10/04/2010] [Indexed: 10/18/2022]
Abstract
The antimicrobial resistance and the character of integrons were determined in 58 Shigella flexneri strains isolated from China. All isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). No intI3 was detected. The typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient E. coli DH5α. The gene cassettes of typical class 1 integrons dfrA17-aadA5 and dfrA12-orfF-aadA2 were detected in 54 strains (93.1%) and 1 strain, respectively. Atypical class 1 integrons located on the chromosome with gene cassettes bla (oxa-30)-aadA1 were detected in 55 isolates (94.8%). All the intI2 positive isolates carried gene cassettes dfrA1-sat1-aadA1. To our knowledge, this is the first report that atypical and typical class 1 integrons coexisted with class 2 integron in multi-drug resistant S. flexneri strains.
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Comparative analysis of the locus of enterocyte effacement and its flanking regions. Infect Immun 2009; 77:3501-13. [PMID: 19506015 DOI: 10.1128/iai.00090-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The attaching-and-effacing (A/E) phenotype mediated by factors derived from the locus of enterocyte effacement (LEE) is a hallmark of clinically important intestinal pathotypes of Escherichia coli, including enteropathogenic (EPEC), atypical EPEC (ATEC), and enterohemorrhagic E. coli strains. Epidemiological studies indicate that the frequency of diarrhea outbreaks caused by ATEC is increasing. Hence, it is of major importance to further characterize putative factors contributing to the pathogenicity of these strains and to gain additional insight into the plasticity and evolutionary aspects of this emerging pathotype. Here, we analyzed the two clinical ATEC isolates B6 (O26:K60) and 9812 (O128:H2) and compared the genetic organizations, flanking regions, and chromosomal insertion loci of their LEE with those of the LEE of other A/E pathogens. Our analysis shows that the core LEE is largely conserved-particularly among genes coding for the type 3 secretion system-whereas genes encoding effector proteins display a higher variability. Chromosomal insertion loci appear to be restricted to selC, pheU, and pheV. In contrast, striking differences were found between the 5'- and 3'-associated flanking regions reflecting the different histories of the various strains and also possibly indicating different lines in evolution.
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Genetics and environmental regulation of Shigella iron transport systems. Biometals 2009; 22:43-51. [PMID: 19130265 DOI: 10.1007/s10534-008-9188-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 12/07/2008] [Indexed: 10/21/2022]
Abstract
Shigella spp. have transport systems for both ferric and ferrous iron. The iron can be taken up as free iron or complexed to a variety of carriers. All Shigella species have both the Feo and Sit systems for acquisition of ferrous iron, and all have at least one siderophore-mediated system for transport of ferric iron. Several of the transport systems, including Sit, Iuc/IutA (aerobactin synthesis and transport), Fec (ferric di-citrate uptake), and Shu (heme transport) are encoded within pathogenicity islands. The presence and the genomic locations of these islands vary considerably among the Shigella species, and even between isolates of the same species. The expression of the iron transport systems is influenced by the concentration of iron and by environmental conditions including the level of oxygen. ArcA and FNR regulate iron transport gene expression as a function of oxygen tension, with the sit and iuc promoters being highly expressed in aerobic conditions, while the feo ferrous iron transporter promoter is most active under anaerobic conditions. The effects of oxygen are also seen in infection of cultured cells by Shigella flexneri; the Sit and Iuc systems support plaque formation under aerobic conditions, whereas Feo allows plaque formation anaerobically.
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48
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Abstract
Antigen 43 (Ag43) is an abundant outer membrane protein in Escherichia coli belonging to the autotransporter family. Structure-function relationships of Ag43 proposed on the basis of experimental work and in silico analysis are discussed in context of insights derived from molecular modeling. New sequence analysis sheds light on the phylogeny of the allelic variants of the Ag43-encoding gene and identifies two distinct families that appear to be distributed between specific pathogenic and commensal isolates. The molecular mechanism that controls expression by phase variation to create population heterogeneity is discussed. Proposed roles of Ag43 expression for E. coli are summarized and the studies are put into perspective regarding the role of allelic variants, genetic background of the bacterial strain, and control of expression by phase variation. We conclude that future studies need to take into account these variables to obtain a complete understanding of the contribution of Ag43 expression to E. coli biology.
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Affiliation(s)
- Marjan W van der Woude
- Department of Biology and the Hull York Medical School, University of York, York Y010 5YW, United Kingdom.
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Characterization of pUO-StVR2, a virulence-resistance plasmid evolved from the pSLT virulence plasmid of Salmonella enterica serovar Typhimurium. Antimicrob Agents Chemother 2008; 52:4514-7. [PMID: 18852276 DOI: 10.1128/aac.00563-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
pUO-StVR2 is a virulence-resistance plasmid which originated from pSLT of Salmonella enterica serovar Typhimurium through acquisition of a complex resistance island, flanked by regions that provide a toxin-antitoxin system and an iron uptake system. The presence of resistance and virulence determinants on the same plasmid allows coselection of both properties, potentially increasing health risks.
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Molecular pathogenesis of Shigella spp.: controlling host cell signaling, invasion, and death by type III secretion. Clin Microbiol Rev 2008; 21:134-56. [PMID: 18202440 DOI: 10.1128/cmr.00032-07] [Citation(s) in RCA: 400] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Shigella spp. are gram-negative pathogenic bacteria that evolved from harmless enterobacterial relatives and may cause devastating diarrhea upon ingestion. Research performed over the last 25 years revealed that a type III secretion system (T3SS) encoded on a large plasmid is a key virulence factor of Shigella flexneri. The T3SS determines the interactions of S. flexneri with intestinal cells by consecutively translocating two sets of effector proteins into the target cells. Thus, S. flexneri controls invasion into EC, intra- and intercellular spread, macrophage cell death, as well as host inflammatory responses. Some of the translocated effector proteins show novel biochemical activities by which they intercept host cell signal transduction pathways. An understanding of the molecular mechanisms underlying Shigella pathogenesis will foster the development of a safe and efficient vaccine, which, in parallel with improved hygiene, should curb infections by this widespread pathogen.
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