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Delago J, Miller EA, Flores-Figueroa C, Munoz-Aguayo J, Cardona C, Smith AH, Johnson TJ. Survey of clinical and commensal Escherichia coli from commercial broilers and turkeys, with emphasis on high-risk clones using APECTyper. Poult Sci 2023; 102:102712. [PMID: 37156077 DOI: 10.1016/j.psj.2023.102712] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/09/2023] [Indexed: 05/10/2023] Open
Abstract
Molecular characterization of avian pathogenic Escherichia coli (APEC) is challenging due to the complex nature of its associated disease, colibacillosis, in poultry. Numerous efforts have been made toward defining APEC, and it is becoming clear that certain clonal backgrounds are predictive of an avian E. coli isolate's virulence potential. Thus, APEC can be further differentiated as high-risk APEC based upon their clonal background's virulence potential. However, less clear is the degree of overlap between clinical isolates of differing bird type, and between clinical and gastrointestinal isolates. This study aimed to determine genomic similarities and differences between such populations, comparing commercial broiler vs. turkey isolates, and clinical vs. gastrointestinal isolates. Differences were observed in Clermont phylogenetic groups between isolate populations, with B2 as the dominant group in turkey clinical isolates and G as the dominant group in broiler clinical isolates. Nearly all clinical isolates were classified as APEC using a traditional gene-based typing scheme, whereas 53.4% and 44.1% of broiler and turkey gastrointestinal isolates were classified as APEC, respectively. High-risk APEC were identified among 31.0% and 46.9% of broiler and turkey clinical isolates, compared with 5.7% and 2.9% of broiler and turkey gastrointestinal isolates. As found in previous studies, no specific known virulence or fitness gene sets were identified which universally differentiate between clinical and gastrointestinal isolates. This study further demonstrates the utility of a hybrid APEC typing approach, considering both plasmid content and clonal background, for the identification of dominant and highly virulent APEC clones in poultry production.
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Affiliation(s)
- Jodi Delago
- Arm and Hammer Animal and Food Production, Waukesha, WI, 53186, USA
| | - Elizabeth A Miller
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, USA
| | | | | | - Carol Cardona
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, USA
| | | | - Timothy J Johnson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, USA; Mid-Central Research and Outreach Center, University of Minnesota, Willmar, MN, USA.
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2
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Suzuki K, Kaseyama-Takemoto H. Simultaneous production of N-acetylheparosan and recombinant chondroitin using gene-engineered Escherichia coli K5. Heliyon 2023; 9:e14815. [PMID: 37095938 PMCID: PMC10121815 DOI: 10.1016/j.heliyon.2023.e14815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
N-Acetylheparosan and chondroitin are increasingly needed as alternative sources of animal-derived sulfated glycosaminoglycans (GAGs) and as inert substances in medical devices and pharmaceuticals. The N-acetylheparosan productivity of E. coli K5 has achieved levels of industrial applications, whereas E.coli K4 produces a relatively lower amount of fructosylated chondroitin. In this study, the K5 strain was gene-engineered to co-express K4-derived, chondroitin-synthetic genes, namely kfoA and kfoC. The productivities of total GAG and chondroitin in batch culture were 1.2 g/L and 1.0 g/L respectively, which were comparable to the productivity of N-acetylheparosan in the wild K5 strain (0.6-1.2 g/L). The total GAG of the recombinant K5 was partially purified by DEAE-cellulose chromatography and was subjected to degradation tests with specific GAG-degrading enzymes combined with HPLC and 1H NMR analyses. The results indicated that the recombinant K5 simultaneously produced both 100-kDa chondroitin and 45-kDa N-acetylheparosan at a weight ratio of approximately 4:1. The content of chondroitin in total GAG partially purified was 73.2%. The molecular weight of recombinant chondroitin (100 kDa) was 5-10 times higher than that of commercially available chondroitin sulfate. These results indicated that the recombinant K5 strain acquired the chondroitin-producing ability without altering the total GAG productivity of the host.
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3
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Afolayan AO, Aboderin AO, Oaikhena AO, Odih EE, Ogunleye VO, Adeyemo AT, Adeyemo AT, Bejide OS, Underwood A, Argimón S, Abrudan M, Egwuenu A, Ihekweazu C, Aanensen DM, Okeke IN. An ST131 clade and a phylogroup A clade bearing an O101-like O-antigen cluster predominate among bloodstream Escherichia coli isolates from South-West Nigeria hospitals. Microb Genom 2022; 8:mgen000863. [PMID: 36748556 PMCID: PMC9837563 DOI: 10.1099/mgen.0.000863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 06/15/2022] [Indexed: 12/23/2022] Open
Abstract
Escherichia coli bloodstream infections are typically attributed to a limited number of lineages that carry virulence factors associated with invasiveness. In Nigeria, the identity of circulating clones is largely unknown and surveillance of their antimicrobial resistance has been limited. We verified and whole-genome sequenced 68 2016-2018 bloodstream E. coli isolates from three sentinel sites in South-Western Nigeria and susceptibility tested 67 of them. Resistance to antimicrobials commonly used in Nigeria was high, with 67 (100 %), 62 (92.5 %), 53 (79.1 %) and 37 (55.2 %) showing resistance to trimethoprim, ampicillin, ciprofloxacin and aminoglycosides, respectively. Thirty-five (51 %) isolates carried extended-spectrum β-lactamase genes and 32 (91 %) of these were multidrug resistant. All the isolates were susceptible to carbapenems and colistin. The strain set included globally disseminated high-risk clones from sequence type (ST)12 (2), ST131 (12) and ST648 (4). Twenty-three (33.8 %) of the isolates clustered within two clades. The first of these consisted of ST131 strains, comprising O16:H5 and O25:H4 sub-lineages. The second was an ST10-ST167 complex clade comprising strains carrying O-antigen and capsular genes of likely Klebsiella origin, identical to those of avian pathogenic E. coli Sanji, and serotyped in silico as O89, O101 or ONovel32, depending on the tool used. Four temporally associated ST90 strains from one sentinel were closely related enough to suggest that at least some of them represented a retrospectively detected outbreak cluster. Our data implicate a broad repertoire of E. coli isolates associated with bloodstream infections in South-West Nigeria. Continued genomic surveillance is valuable for tracking clones of importance and for outbreak identification.
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Affiliation(s)
- Ayorinde O. Afolayan
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
| | - A. Oladipo Aboderin
- Department of Medical Microbiology and Parasitology, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State, Nigeria
| | - Anderson O. Oaikhena
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
| | - Erkison Ewomazino Odih
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
| | - Veronica O. Ogunleye
- Department of Medical Microbiology and Parasitology, University College Hospital, Ibadan, Oyo State, Nigeria
| | - Adeyemi T. Adeyemo
- Department of Medical Microbiology and Parasitology, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State, Nigeria
| | - Abolaji T. Adeyemo
- Department of Medical Microbiology and Parasitology, University of Osun Teaching Hospital, Osogbo, Osun State, Nigeria
| | - Oyeniyi S. Bejide
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
| | - Anthony Underwood
- Centre for Genomic Pathogen Surveillance, Big Data Institute, University of Oxford, Old Road Campus, Oxford, UK
- Wellcome Genome Campus, Hinxton, UK
| | - Silvia Argimón
- Centre for Genomic Pathogen Surveillance, Big Data Institute, University of Oxford, Old Road Campus, Oxford, UK
- Wellcome Genome Campus, Hinxton, UK
| | - Monica Abrudan
- Centre for Genomic Pathogen Surveillance, Big Data Institute, University of Oxford, Old Road Campus, Oxford, UK
- Wellcome Genome Campus, Hinxton, UK
| | | | | | - David M. Aanensen
- Centre for Genomic Pathogen Surveillance, Big Data Institute, University of Oxford, Old Road Campus, Oxford, UK
- Wellcome Genome Campus, Hinxton, UK
| | - Iruka N. Okeke
- Global Health Research Unit for the Genomic Surveillance of Antimicrobial Resistance, Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
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Hasan RN, Jasim SA, Ali YH. Detection of fimH, kpsMTII, hlyA, and traT genes in Escherichia coli isolated from Iraqi patients with cystitis. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2021.101468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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The role of major virulence factors and pathogenicity of adherent-invasive Escherichia coli in patients with Crohn's disease. GASTROENTEROLOGY REVIEW 2020; 15:279-288. [PMID: 33777266 PMCID: PMC7988836 DOI: 10.5114/pg.2020.93235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/04/2019] [Indexed: 12/12/2022]
Abstract
Inflammatory bowel disease (IBD) is a term that describes Crohn's disease (CD) and ulcerative colitis (UC), and these two conditions are characterised by chronic inflammation of the gastrointestinal tract. Dysbiosis of intestinal microbiota has been consistently linked to patients with IBD. In the last two decades, the progressive implication of adherent-invasive Escherichia coli (AIEC) pathogenesis in patients with CD has been increasing. Here we discuss recent findings that indicate the role and mechanisms of AIEC in IBD. We also highlight AIEC virulence factor genes and mechanisms that suggest an important role in the severity of inflammation in CD patients. Finally, we emphasise data on the prevalence of AIEC in CD patients.
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Reid CJ, McKinnon J, Djordjevic SP. Clonal ST131- H22 Escherichia coli strains from a healthy pig and a human urinary tract infection carry highly similar resistance and virulence plasmids. Microb Genom 2019; 5. [PMID: 31526455 PMCID: PMC6807379 DOI: 10.1099/mgen.0.000295] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The interplay between food production animals, humans and the environment with respect to the transmission of drug-resistant pathogens is widely debated and poorly understood. Pandemic uropathogenic Escherichia coli ST131-H30Rx, with conserved fluoroquinolone and cephalosporin resistance, are not frequently identified in animals. However, the phylogenetic precursor lineage ST131-H22 in animals and associated meat products is being reported with increasing frequency. Here we characterized two highly related ST131-H22 strains, one from a healthy pig and the other from a human infection (in 2007 and 2009, respectively). We used both long and short genome sequencing and compared them to ST131-H22 genome sequences available in public repositories. Even within the context of H22 strains, the two strains in question were highly related, separated by only 20 core SNPs. Furthermore, they were closely related to a faecal strain isolated in 2010 from a geographically distinct, healthy human in New South Wales, Australia. The porcine and hospital strains carried highly similar HI2-ST3 multidrug resistant plasmids with differences in the hospital strain arising due to IS-mediated insertions and rearrangements. Near identical ColV plasmids were also present in both strains, further supporting their shared evolutionary history. This work highlights the importance of adopting a One Health approach to genomic surveillance to gain insights into pathogen evolution and spread.
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Affiliation(s)
- Cameron J Reid
- The i3 institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Jessica McKinnon
- The i3 institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Steven P Djordjevic
- The i3 institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
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Daga AP, Koga VL, Soncini JGM, de Matos CM, Perugini MRE, Pelisson M, Kobayashi RKT, Vespero EC. Escherichia coli Bloodstream Infections in Patients at a University Hospital: Virulence Factors and Clinical Characteristics. Front Cell Infect Microbiol 2019; 9:191. [PMID: 31245301 PMCID: PMC6563721 DOI: 10.3389/fcimb.2019.00191] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/20/2019] [Indexed: 01/24/2023] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) isolates are responsible for many bloodstream infections. The aim of this study was to characterize E. coli isolated from the bloodstreams of patients (n = 48) at the University Hospital in Brazil. Epidemiological data were obtained through the analysis of medical records and laboratory tests. By PCR analysis, we investigated the presence of virulence factors (VFs), pathogenicity islands (PAIs), extended-spectrum β-lactamase (ESBL), phylogenetic classifications (A, B1, B2, C, D, E, and F) and molecular genotype by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The mortality analysis showed that 33.3% of the deaths were associated with bacteraemia due to E. coli infections; in addition, an age between 60 and 75 years (p < 0.001; OR = 6.3[2.1–18.9]) and bacteraemia with an abdominal origin (p = 0.02; OR = 5[1.2–20.5]) were risk factors for the severity of the infection. Additionally, the presence of the afa gene was associated with mortality due to E. coli bacteraemia (p = 0.027; OR = 11.4[1.5–85.7]). Immunosuppression (27.1%), intestinal diseases (25.0%) and diabetes (18.8%), were prevalent among patients, and most of the bacteraemia cases were secondary to urinary tract infections (50.0%). The serum resistance gene traT was present in 77.1% of isolates, group capsular 2 (kpsMT II) was present in 45.8% and the K5 capsule was present in 20.8% of isolates. The isolates also showed a high prevalence for the siderophore yersiniabactina (fyuA) (70.8%) and PAI IV536 (77.1%). Phylogenetic analysis showed that group B2 (45.8%) was the most prevalent, and was the phylogroup that had a higher prevalence of VFs and PAIs. However, in this study, a considerable number of isolated bacteria were classified as group B1 (18.8%) and as group E (14.6%). Eight (16.7%) isolates were resistant to third and fourth generation cephalosporin and group CTX-M-1 (CTX-M-15) was the most prevalent ESBL type. The molecular genotyping showed two clonal lineages and several isolates that were not related to each other. This study provides additional information on the epidemiological and molecular characteristics of E. coli bloodstream infections in Brazil.
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Affiliation(s)
- Ana Paula Daga
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
| | - Vanessa Lumi Koga
- Laboratory of Microbiology, Department of Microbiology, State University of Londrina, Londrina, Brazil
| | - João Gabriel Material Soncini
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
| | - Caroline Martins de Matos
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
| | - Marcia Regina Eches Perugini
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
| | - Marsileni Pelisson
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
| | | | - Eliana Carolina Vespero
- Laboratory of Clinical Microbiology, Department of Pathology, Clinical and Toxicological Analysis, Health Sciences Center, State University of Londrina, Londrina, Brazil
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Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) are important pathogens in humans and certain animals. Molecular epidemiological analyses of ExPEC are based on structured observations of E. coli strains as they occur in the wild. By assessing real-world phenomena as they occur in authentic contexts and hosts, they provide an important complement to experimental assessment. Fundamental to the success of molecular epidemiological studies are the careful selection of subjects and the use of appropriate typing methods and statistical analysis. To date, molecular epidemiological studies have yielded numerous important insights into putative virulence factors, host-pathogen relationships, phylogenetic background, reservoirs, antimicrobial-resistant strains, clinical diagnostics, and transmission pathways of ExPEC, and have delineated areas in which further study is needed. The rapid pace of discovery of new putative virulence factors and the increasing awareness of the importance of virulence factor regulation, expression, and molecular variation should stimulate many future molecular epidemiological investigations. The growing sophistication and availability of molecular typing methodologies, and of the new computational and statistical approaches that are being developed to address the huge amounts of data that whole genome sequencing generates, provide improved tools for such studies and allow new questions to be addressed.
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Hong Y, Cunneen MM, Reeves PR. Two extremely divergent sequence forms of the genes that define Escherichia coli group 3 capsules suggest a very long history since their common ancestor. FEMS Microbiol Lett 2019; 366:5480460. [PMID: 31089702 DOI: 10.1093/femsle/fnz091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/25/2019] [Indexed: 11/14/2022] Open
Abstract
Capsules are a critical virulence factor in many pathogenic Escherichia coli, of which groups 2 and 3 capsules are synthesised by the ABC transporter pathway. The well-studied forms are in group 2 and much of our knowledge of group 3 is inferred from our understanding of group 2. We analyse six group 3 gene clusters including representatives of K10, K11 and K96, and find unexpected diversity. Groups 2 and 3 both have gene clusters with terminal regions 1 and 3 containing mostly genes shared by all members of both groups, plus a central region 2, that in group 2 has the genes for synthesising the serotype-specific repeat unit. We find that in all but one case group 3 gene clusters include, in addition to serotype-specific genes, a previously unrecognised set of shared genes in region 2 that probably codes for an additional structural element. Also, the six shared genes in regions 1 and 3 of group 3 exist in two very different sequence forms. It appears that the E. coli ABC transporter capsules have a very long history, with more fundamental diversity present in group 3, but greater diversity in the exposed strongly antigenic serotype-specific component encoded by region 2.
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Affiliation(s)
- Yaoqin Hong
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW 2006, Australia.,Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4006, Australia
| | - Monica M Cunneen
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW 2006, Australia
| | - Peter R Reeves
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW 2006, Australia
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Wang Y, Andole Pannuri A, Ni D, Zhou H, Cao X, Lu X, Romeo T, Huang Y. Structural Basis for Translocation of a Biofilm-supporting Exopolysaccharide across the Bacterial Outer Membrane. J Biol Chem 2016; 291:10046-57. [PMID: 26957546 DOI: 10.1074/jbc.m115.711762] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 12/14/2022] Open
Abstract
The partially de-N-acetylated poly-β-1,6-N-acetyl-d-glucosamine (dPNAG) polymer serves as an intercellular biofilm adhesin that plays an essential role for the development and maintenance of integrity of biofilms of diverse bacterial species. Translocation of dPNAG across the bacterial outer membrane is mediated by a tetratricopeptide repeat-containing outer membrane protein, PgaA. To understand the molecular basis of dPNAG translocation, we determined the crystal structure of the C-terminal transmembrane domain of PgaA (residues 513-807). The structure reveals that PgaA forms a 16-strand transmembrane β-barrel, closed by four loops on the extracellular surface. Half of the interior surface of the barrel that lies parallel to the translocation pathway is electronegative, suggesting that the corresponding negatively charged residues may assist the secretion of the positively charged dPNAG polymer. In vivo complementation assays in a pgaA deletion bacterial strain showed that a cluster of negatively charged residues proximal to the periplasm is necessary for biofilm formation. Biochemical analyses further revealed that the tetratricopeptide repeat domain of PgaA binds directly to the N-deacetylase PgaB and is critical for biofilm formation. Our studies support a model in which the positively charged PgaB-bound dPNAG polymer is delivered to PgaA through the PgaA-PgaB interaction and is further targeted to the β-barrel lumen of PgaA potentially via a charge complementarity mechanism, thus priming the translocation of dPNAG across the bacterial outer membrane.
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Affiliation(s)
- Yan Wang
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Archana Andole Pannuri
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32611-0700
| | - Dongchun Ni
- Department of Cardiovascular Diseases, Tianjin Xiqing Hospital, Tianjin 300380, China
| | - Haizhen Zhou
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiou Cao
- School of Life Sciences, Peking University, Beijing 100871, China, and
| | - Xiaomei Lu
- Dongguan Institute of Pediatrics, the Eighth People's Hospital of Dongguan, Dongguan 523325, Guangdong Province, China
| | - Tony Romeo
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32611-0700,
| | - Yihua Huang
- From the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China,
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Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized E. coli strains that possess the ability to overcome or subvert host defenses and cause extraintestinal disease, are important pathogens in humans and certain animals. Molecular epidemiological analysis has led to an appreciation of ExPEC as being distinct from other E. coli (including intestinal pathogenic and commensal variants) and has offered insights into the ecology, evolution, reservoirs, transmission pathways, host-pathogen interactions, and pathogenetic mechanisms of ExPEC. Molecular epidemiological analysis also provides an essential complement to experimental assessment of virulence mechanisms. This chapter first reviews the basic conceptual and methodological underpinnings of the molecular epidemiological approach and then summarizes the main aspects of ExPEC that have been investigated using this approach.
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12
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Goldstone RJ, Popat R, Schuberth HJ, Sandra O, Sheldon IM, Smith DGE. Genomic characterisation of an endometrial pathogenic Escherichia coli strain reveals the acquisition of genetic elements associated with extra-intestinal pathogenicity. BMC Genomics 2014; 15:1075. [PMID: 25481482 PMCID: PMC4298941 DOI: 10.1186/1471-2164-15-1075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 11/24/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Strains of Escherichia coli cause a wide variety of intestinal and extra-intestinal diseases in both humans and animals, and are also often found in healthy individuals or the environment. Broadly, a strong phylogenetic relationship exists that distinguishes most E. coli causing intestinal disease from those that cause extra-intestinal disease, however, isolates within a recently described subclass of Extra-Intestinal Pathogenic E. coli (ExPEC), termed endometrial pathogenic E. coli, tend to be phylogenetically distant from the vast majority of characterised ExPECs, and more closely related to human intestinal pathogens. In this work, we investigate the genetic basis for ExPEC infection in the prototypic endometrial pathogenic E. coli strain MS499. RESULTS By investigating the genome of MS499 in comparison with a range of other E. coli sequences, we have discovered that this bacterium has acquired substantial lengths of DNA which encode factors more usually associated with ExPECs and less frequently found in the phylogroup relatives of MS499. Many of these acquired factors, including several iron acquisition systems and a virulence plasmid similar to that found in several ExPECs such as APEC O1 and the neonatal meningitis E. coli S88, play characterised roles in a variety of typical ExPEC infections and appear to have been acquired recently by the evolutionary lineage leading to MS499. CONCLUSIONS Taking advantage of the phylogenetic relationship we describe between MS499 and several other closely related E. coli isolates from across the globe, we propose a step-wise evolution of a novel clade of sequence type 453 ExPECs within phylogroup B1, involving the recruitment of ExPEC virulence factors into the genome of an ancestrally non-extraintestinal E. coli, which has repurposed this lineage with the capacity to cause extraintestinal disease. These data reveal the genetic components which may be involved in this phenotype switching, and argue that horizontal gene exchange may be a key factor in the emergence of novel lineages of ExPECs.
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Affiliation(s)
| | | | | | | | | | - David G E Smith
- Institute for Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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13
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Yuan B, Cheng A, Wang M. Polysaccharide export outer membrane proteins in Gram-negative bacteria. Future Microbiol 2013; 8:525-35. [DOI: 10.2217/fmb.13.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Polysaccharide export outer membrane proteins of Gram-negative bacteria are involved in the export of polysaccharides across the outer membrane. The mechanisms of polysaccharide export across the outer membrane in Gram-negative bacteria are not yet completely clear. However, the mechanisms of polysaccharide assembly in Escherichia coli have been intensively investigated. Here, we mainly review the current understanding of the assembly mechanisms of group 1 capsular polysaccharide, group 2 capsular polysaccharide and lipopolysaccharide of E. coli, and the current structures and interactions of some polysaccharide export outer membrane proteins with other proteins involved in polysaccharide export in Gram-negative bacteria. In addition, LptD may be targeted by peptidomimetic antibiotics in Gram-negative bacteria. We also give insights into the directions of future research regarding the mechanisms of polysaccharide export.
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Affiliation(s)
- Biao Yuan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Chengdu City, Sichuan 611130, China
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, 46 Xinkang Road, Ya’an, Sichuan 625014, China
- Key Laboratory of Animal Disease & Human Health of Sichuan Province, Sichuan Agricultural University, Wenjiang, Chengdu city, Sichuan 611130, China
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14
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Janssen PJ, Van Houdt R, Moors H, Monsieurs P, Morin N, Michaux A, Benotmane MA, Leys N, Vallaeys T, Lapidus A, Monchy S, Médigue C, Taghavi S, McCorkle S, Dunn J, van der Lelie D, Mergeay M. The complete genome sequence of Cupriavidus metallidurans strain CH34, a master survivalist in harsh and anthropogenic environments. PLoS One 2010; 5:e10433. [PMID: 20463976 PMCID: PMC2864759 DOI: 10.1371/journal.pone.0010433] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 03/29/2010] [Indexed: 11/21/2022] Open
Abstract
Many bacteria in the environment have adapted to the presence of toxic heavy metals. Over the last 30 years, this heavy metal tolerance was the subject of extensive research. The bacterium Cupriavidus metallidurans strain CH34, originally isolated by us in 1976 from a metal processing factory, is considered a major model organism in this field because it withstands milli-molar range concentrations of over 20 different heavy metal ions. This tolerance is mostly achieved by rapid ion efflux but also by metal-complexation and -reduction. We present here the full genome sequence of strain CH34 and the manual annotation of all its genes. The genome of C. metallidurans CH34 is composed of two large circular chromosomes CHR1 and CHR2 of, respectively, 3,928,089 bp and 2,580,084 bp, and two megaplasmids pMOL28 and pMOL30 of, respectively, 171,459 bp and 233,720 bp in size. At least 25 loci for heavy-metal resistance (HMR) are distributed over the four replicons. Approximately 67% of the 6,717 coding sequences (CDSs) present in the CH34 genome could be assigned a putative function, and 9.1% (611 genes) appear to be unique to this strain. One out of five proteins is associated with either transport or transcription while the relay of environmental stimuli is governed by more than 600 signal transduction systems. The CH34 genome is most similar to the genomes of other Cupriavidus strains by correspondence between the respective CHR1 replicons but also displays similarity to the genomes of more distantly related species as a result of gene transfer and through the presence of large genomic islands. The presence of at least 57 IS elements and 19 transposons and the ability to take in and express foreign genes indicates a very dynamic and complex genome shaped by evolutionary forces. The genome data show that C. metallidurans CH34 is particularly well equipped to live in extreme conditions and anthropogenic environments that are rich in metals.
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Affiliation(s)
- Paul J Janssen
- Molecular and Cellular Biology, Belgian Nuclear Research Center SCK*CEN, Mol, Belgium.
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Zhao L, Chen X, Zhu X, Yang W, Dong L, Xu X, Gao S, Liu X. Prevalence of virulence factors and antimicrobial resistance of uropathogenic Escherichia coli in Jiangsu province (China). Urology 2009; 74:702-7. [PMID: 19362346 DOI: 10.1016/j.urology.2009.01.042] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 12/23/2008] [Accepted: 01/19/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To determine the prevalence of virulence factors and the antimicrobial susceptibilities of uropathogenic Escherichia coli isolates in Jiangsu province, China. METHODS A total of 202 uropathogenic E. coli isolates were characterized for O serogroups, virulence factor genes, the antimicrobial susceptibilities, and the phylogenetic groups. The antibiotic-resistance phenotypes in relation to virulence factor genes were assessed by statistical analysis. RESULTS O1 was the most prevalent serogroup, and D and B2 were the most frequent phylogenetic groups. Of the 33 tested virulence genes, feoB and fimH were the most prevalent. Of the 15 antimicrobial agents tested, resistance to nalidixic acid, mezlocillin, ampicillin, and tetracycline was the most frequent. All isolates were multiresistant, and 73% were resistant to trimethoprim-sulfamethoxazole. Cefotaxime-, cefoxitin-, chloramphenicol-, and nitrofurantoin-resistant isolates had reduced virulence factor genes compared with susceptible strains. CONCLUSIONS In Jiangsu province, the problem of antibiotic resistance for uropathogenic E. coli is rather serious and empiric treatment of urinary tract infections with all the antibiotics we tested is no longer appropriate. Cefotaxime-, cefoxitin-, chloramphenicol-, and nitrofurantoin-resistant isolates have a reduced virulence factor genes compared with susceptible strains.
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Affiliation(s)
- Lixiang Zhao
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
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16
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Corbett D, Roberts IS. Capsular Polysaccharides in Escherichia coli. ADVANCES IN APPLIED MICROBIOLOGY 2008; 65:1-26. [DOI: 10.1016/s0065-2164(08)00601-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Russo TA, Beanan JM, Olson R, Genagon SA, MacDonald U, Cope JJ, Davidson BA, Johnston B, Johnson JR. A killed, genetically engineered derivative of a wild-type extraintestinal pathogenic E. coli strain is a vaccine candidate. Vaccine 2007; 25:3859-70. [PMID: 17306426 PMCID: PMC1913199 DOI: 10.1016/j.vaccine.2007.01.100] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Revised: 01/18/2007] [Accepted: 01/23/2007] [Indexed: 11/28/2022]
Abstract
Infections due to extraintestinal pathogenic E. coli (ExPEC) result in significant morbidity, mortality and increased healthcare costs. An efficacious vaccine against ExPEC would be desirable. In this report, we explore the use of killed-whole E. coli as a vaccine immunogen. Given the diversity of capsule and O-antigens in ExPEC, we have hypothesized that alternative targets are viable vaccine candidates. We have also hypothesized that immunization with a genetically engineered strain that is deficient in the capsule and O-antigen will generate a greater immune response against antigens other than the capsular and O-antigen epitopes than a wild-type strain. Lastly, we hypothesize that mucosal immunization with killed E. coli has the potential to generate a significant immune response. In this study, we demonstrated that nasal immunization with a formalin-killed ExPEC derivative deficient in capsule and O-antigen results in a significantly greater overall humoral response compared to its wild-type derivative (which demonstrates that capsule and/or the O-antigen impede the development of an optimal humoral immune response) and a significantly greater immune response against non-capsular and O-antigen epitopes. These antibodies also bound to a subset of heterologous ExPEC strains and enhanced neutrophil-mediated bactericidal activity against the homologous and a heterologous strain. Taken together, these studies support the concept that formalin-killed genetically engineered ExPEC derivatives are whole cell vaccine candidates to prevent infections due to ExPEC.
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Affiliation(s)
- Thomas A Russo
- Department of Medicine, University at Buffalo, and Veterans Administration Western New York Healthcare System, Buffalo, NY 14214, United States.
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18
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Johnson JR, Russo TA. Molecular epidemiology of extraintestinal pathogenic (uropathogenic) Escherichia coli. Int J Med Microbiol 2005; 295:383-404. [PMID: 16238015 DOI: 10.1016/j.ijmm.2005.07.005] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Molecular epidemiological analyses of extraintestinal pathogenic Escherichia coli (ExPEC), which are also called "uropathogenic E. coli" since they are the principle pathogens in urinary tract infection, involve structured observations of E. coli as they occur in the wild. Careful selection of subjects and use of appropriate methods for genotyping and statistical analysis are required for optimal results. Molecular epidemiological studies have helped to clarify the host-pathogen relationships, phylogenetic background, reservoirs, and transmission pathways of ExPEC, to assess potential vaccine candidates, and to delineate areas for further study. Ongoing discovery of new putative virulence factors (VFs), increasing awareness of the importance of VF expression and molecular variants of VFs, and growing appreciation of transmission as an important contributor to ExPEC infections provide abundant stimulus for future molecular epidemiological studies. Published by Elsevier GmbH.
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Affiliation(s)
- James R Johnson
- Mucosal and Vaccine Research Center, Infectious Diseases (111F), VA Medical Center, 1 Veterans Drive, Minneapolis, MN 55417, USA.
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Power ML, Littlefield-Wyer J, Gordon DM, Veal DA, Slade MB. Phenotypic and genotypic characterization of encapsulated Escherichia coli isolated from blooms in two Australian lakes. Environ Microbiol 2005; 7:631-40. [PMID: 15819845 DOI: 10.1111/j.1462-2920.2005.00729.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Escherichia coli has long been used as an indicator organism for water quality assessment. Recently there has been an accumulation of evidence that suggests some strains of this organism are able to proliferate in the environment, a characteristic that would detract from its utility as an indicator of faecal pollution. Phenotypic and genotypic characterization of E. coli isolated from blooms in two Australian lakes, separated by a distance of approximately 200 km, identified that the blooms were dominated by three E. coli strains. A major phenotypic similarity among the three bloom strains was the presence of a group 1 capsule. Genetic characterization of a conserved region of the cps gene cluster, which encodes group 1 capsules, identified a high degree of genetic variation within the bloom isolates. This differs from previously described encapsulated E. coli strains which are highly conserved at the cps locus. The phenotypic or genotypic profiles of the bloom strains were not identified in 435 E. coli strains isolated from vertebrates. The occurrence of these encapsulated strains suggests that some E. coli have evolved a free-living lifestyle and do not require a host in order to proliferate. The presence of the same three strains in bloom events in different geographical regions of a temperate climate, and at different times, indicates that free-living E. coli strains are able to persist in these water reservoirs. This study provides further evidence of circumstances where caution is required in using E. coli as an indicator organism for water quality.
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Affiliation(s)
- Michelle L Power
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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20
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Schuchert JA, Inzana TJ, Angen Ø, Jessing S. Detection and identification of Actinobacillus pleuropneumoniae serotypes 1, 2, and 8 by multiplex PCR. J Clin Microbiol 2004; 42:4344-8. [PMID: 15365041 PMCID: PMC516343 DOI: 10.1128/jcm.42.9.4344-4348.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiplex PCR assays were developed to identify Actinobacillus pleuropneumoniae serotypes 1, 2, and 8. Primers designed for the conserved capsular polysaccharide (CP) export region amplified a 489-bp DNA fragment from all serotypes. Primers specific to the CP biosynthesis regions of serotypes 1, 2, and 8 amplified fragments of 1.6 kb, 1.7 kb, and 970 bp from only their respective serotypes.
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Affiliation(s)
- Jennifer A Schuchert
- Center for Molecular Medicine and Infectious Diseases, Virginia-Maryland Regional College of Veterinary Medicine, 1410 Prices Fork Rd., Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0342, USA
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21
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Johnson JR, O'Bryan TT. Detection of the Escherichia coli group 2 polysaccharide capsule synthesis Gene kpsM by a rapid and specific PCR-based assay. J Clin Microbiol 2004; 42:1773-6. [PMID: 15071046 PMCID: PMC387594 DOI: 10.1128/jcm.42.4.1773-1776.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A rapid and simple PCR-based assay for detection of the group 2 capsule synthesis gene kpsM of Escherichia coli was designed and validated. When combined with the published group 2 primers (kpsIIf, 5'-GCGCATTTGCTGATACTGTTG-3'; kpsIIr, 5'-CATCCAGACGATAAGCATGAGCA-3'), the new primers (the kpsIIf primer and a new reverse primer K2r, 5'-AGGTAGTTCAGACTCACACCT-3') allowed specific identification by exclusion of the heretofore elusive K2 kpsM variant. The primers yielded the predicted amplicon when multiplexed with other primers and used under varied assay conditions, including a range of concentrations of individual reaction mixture ingredients and of annealing temperatures (from 54 to 64 degrees C).
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Affiliation(s)
- James R Johnson
- Mucosal and Vaccine Research Center, Minneapolis VA Medical Center, Minnesota.
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22
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Russo TA, Davidson BA, Carlino-MacDonald UB, Helinski JD, Priore RL, Knight PR. The effects of Escherichia coli capsule, O-antigen, host neutrophils, and complement in a rat model of Gram-negative pneumonia. FEMS Microbiol Lett 2003; 226:355-61. [PMID: 14553933 DOI: 10.1016/s0378-1097(03)00636-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Gram-negative enteric bacilli are agents of life-threatening pneumonia. The role of the bacterial capsule and O-antigen moiety of lipopolysaccharide in the pathogenesis of Gram-negative pneumonia was assessed. In a rat model of pneumonia the LD(50) of a wild-type extraintestinal pathogenic Escherichia coli strain (CP9) was significantly less than its isogenic derivatives deficient in capsule (CP9.137), O-antigen (CP921) or both capsule and O-antigen (CP923) (P< or =0.003). Studies using complement depleted or neutropenic animals established that both neutrophils and complement are important for the pulmonary clearance of E. coli. Data from these studies also support that capsule and O-antigen serve, at least in part, to counter the complement and neutrophil components of the pulmonary host defense response. Lastly, the contribution of E. coli versus neutrophils in causing lung injury was examined. Findings suggest that E. coli virulence factors and/or non-neutrophil host factors are more important mediators of lung injury than neutrophils. These findings extend our understanding of Gram-negative pneumonia and have treatment implications.
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Affiliation(s)
- Thomas A Russo
- Department of Medicine, Division of Infectious Diseases, 3435 Main St., Biomedical Research Building, Room 141, Buffalo, NY 14214, USA.
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Russo TA, Davidson BA, Topolnycky DM, Olson R, Morrill SA, Knight PR, Murphy PM. Human neutrophil chemotaxis is modulated by capsule and O antigen from an extraintestinal pathogenic Escherichia coli strain. Infect Immun 2003; 71:6435-45. [PMID: 14573665 PMCID: PMC219585 DOI: 10.1128/iai.71.11.6435-6445.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gram-negative enteric bacilli, such as Escherichia coli, are common causes of nosocomial pneumonia. The interaction between pulmonary neutrophils and the infecting pathogen is a critical step in determining the outcome. Previous studies from our laboratory, for which a rat model of pneumonia was used, established that pulmonary neutrophil recruitment was modulated by the E. coli virulence factors capsule and O-specific antigen. To begin to understand the mechanism by which this recruitment occurs, we conducted in vitro and ex vivo chemotaxis assays, for which we used a clinically relevant E. coli isolate (CP9) and isogenic derivatives that were deficient in only the O antigen (CP921) or capsule (CP9.137) as chemoattractants with or without the high-affinity N-formylmethionyl-leucyl-phenylalanine receptor antagonist N-tert-butoxycarbonyl-methionine-leucine-phenylalanine (N-t-BOC). Given that only live E. coli was used for the initial in vitro chemotaxis assays, it was predicted that only N-t-BOC-sensitive chemotaxis would occur. However, both N-t-BOC-sensitive and -insensitive chemotaxis was observed. N-t-BOC-insensitive chemotaxis was mediated in part by interleukin 8, which was produced by neutrophils that had migrated toward E. coli. N-t-BOC-insensitive chemotaxis was only observed when live E. coli bacteria, not cell-free E. coli culture supernatants, were used as chemoattractants, suggesting that a direct E. coli-neutrophil interaction was necessary. The presence of both capsule and O antigen diminished total, N-t-BOC-sensitive, and N-t-BOC-insensitive neutrophil chemotaxis in vitro. The presence of capsule significantly decreased total, N-t-BOC-sensitive, and N-t-BOC-insensitive neutrophil chemotaxis ex vivo when cell-free bronchoalveolar lavage fluid from infected rats was used as the source of chemotactic factors. These effects of E. coli capsule and O antigen on neutrophil chemotaxis are novel, and they expand our understanding of the mechanisms by which these virulence traits contribute to the pathogenesis of gram-negative pneumonia and other extraintestinal infections.
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Affiliation(s)
- Thomas A Russo
- Department of Medicine, The Witebsky Center for Microbial Pathogenesis. Veterans Administration Western New York Healthcare System, University at Buffalo, Buffalo, New York 14214, USA.
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Johnson JR, Lockman HA, Owens K, Jelacic S, Tarr PI. High-frequency secondary mutations after suicide-driven allelic exchange mutagenesis in extraintestinal pathogenic Escherichia coli. J Bacteriol 2003; 185:5301-5. [PMID: 12923106 PMCID: PMC180995 DOI: 10.1128/jb.185.17.5301-5305.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Frequent unintended secondary mutations occurred in extraintestinal pathogenic Escherichia coli strains CP9, CFT073, and RS218 during suicide plasmid-mediated, putatively specific deletions of hlyA, papG allele III, and iha. Pulsed-field gel electrophoresis and PCR analyses demonstrated genomic alterations and/or unintended loss of defined virulence genes (papG, the F7-2 papA allele, iutA, sat, hlyD, and cnf). Caution is warranted when attributing the observed phenotypic changes to the intended mutation.
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Affiliation(s)
- James R Johnson
- Mucosal and Vaccine Research Center, Infectious Diseases (111F), Veterans Affairs Medical Center, One Veterans Drive, Minneapolis, MN 55417, USA.
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25
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Zhang YL, Arakawa E, Leung KY. Novel Aeromonas hydrophila PPD134/91 genes involved in O-antigen and capsule biosynthesis. Infect Immun 2002; 70:2326-35. [PMID: 11953367 PMCID: PMC127894 DOI: 10.1128/iai.70.5.2326-2335.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sequences of the O-antigen and capsule gene clusters of the virulent Aeromonas hydrophila strain PPD134/91 were determined. The O-antigen gene cluster is 17,296 bp long and comprises 17 genes. Seven pathway genes for the synthesis of rhamnose and mannose, six transferase genes, one O unit flippase gene, and one O-antigen chain length determinant gene were identified by amino acid sequence similarity. PCR and Southern blot analysis were performed to survey the distribution of these 17 genes among 11 A. hydrophila strains of different serotypes. A. hydrophila PPD134/91 might belong to serotype O:18, as represented by JCM3980; it contained all the same O-antigen genes as JCM3980 (97 to 100% similarity at the DNA and amino acid levels). The capsule gene cluster of A. hydrophila PPD134/91 is 17,562 bp long and includes 13 genes, which were assembled into three distinct regions similar to those of the group II capsule gene cluster of Escherichia coli and other bacteria. Regions I and III contained four and two capsule transport genes, respectively. Region II had five genes which were highly similar to capsule synthesis pathway genes found in other bacteria. Both the purified O-antigen and capsular polysaccharides increased the ability of the avirulent A. hydrophila strain PPD35/85 to survive in naïve tilapia serum. However, the purified surface polysaccharides had no inhibitory effect on the adhesion of A. hydrophila PPD134/91 to carp epithelial cells.
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Affiliation(s)
- Y L Zhang
- Department of Biological Sciences, Faculty of Science, The National University of Singapore, Singapore 117543
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26
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Genomic Structure of Capsular Determinants. Curr Top Microbiol Immunol 2002. [DOI: 10.1007/978-3-642-56031-6_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Kiss E, Kereszt A, Barta F, Stephens S, Reuhs BL, Kondorosi A, Putnoky P. The rkp-3 gene region of Sinorhizobium meliloti Rm41 contains strain-specific genes that determine K antigen structure. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:1395-403. [PMID: 11768534 DOI: 10.1094/mpmi.2001.14.12.1395] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The rkp-3 region is indispensable for capsular polysaccharide (K antigen) synthesis in Sinorhizobium meliloti Rm41. Strain Rm41 produces a K antigen of strain-specific structure, designated as the KR5 antigen. The data in this report show that the rkp-3 gene region comprises 10 open reading frames involved in bacterial polysaccharide synthesis and export. The predicted amino acid sequences for the rkpL-Q gene products are homologous to enzymes involved in the production of specific sugar moieties, while the putative products of the rkpRST genes show a high degree of similarity to proteins required for transporting polysaccharides to the cell surface. Southern analysis experiments using gene-specific probes suggest that genes involved in the synthesis of the precursor sugars are unique in strain Rm41, whereas sequences coding for export proteins are widely distributed among Sinorhizobium species. Mutations in the rkpL-Q genes result in a modified K antigen pattern and impaired symbiotic capabilities. On this basis, we suggest that these genes are required for the production of the KR5 antigen that is necessary for S. meliloti Rm41 exoB (AK631)-alfalfa (Medicago sativa) symbiosis.
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Affiliation(s)
- E Kiss
- Institute of Genetics, Biological Research Center, Hungarian Academy of Sciences, Szeged
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Johnson JR, Stell AL, Delavari P. Canine feces as a reservoir of extraintestinal pathogenic Escherichia coli. Infect Immun 2001; 69:1306-14. [PMID: 11179292 PMCID: PMC98021 DOI: 10.1128/iai.69.3.1306-1314.2001] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2000] [Accepted: 11/20/2000] [Indexed: 11/20/2022] Open
Abstract
To test the canine reservoir hypothesis of extraintestinal pathogenic Escherichia coli (ExPEC), 63 environmental canine fecal deposits were evaluated for the presence of ExPEC by a combination of selective culturing, extended virulence genotyping, hemagglutination testing, O serotyping, and PCR-based phylotyping. Overall, 30% of canine fecal samples (56% of those that yielded viable E. coli) contained papG-positive E. coli, usually as the predominant E. coli strain and always possessing papG allele III (which encodes variant III of the P-fimbrial adhesin molecule PapG). Multiple other virulence-associated genes typical of human ExPEC were prevalent among the canine fecal isolates. According to serotyping, virulence genotyping, and random amplified polymorphic DNA analysis, over 50% of papG-positive fecal E. coli could be directly correlated with specific human clinical isolates from patients with cystitis, pyelonephritis, bacteremia, or meningitis, including archetypal human ExPEC strains 536, CP9, and RS218. Five canine fecal isolates and (clonally related) archetypal human pyelonephritis isolate 536 were found to share a novel allele of papA (which encodes the P-fimbrial structural subunit PapA). These data confirm that ExPEC representing known virulent clones are highly prevalent in canine feces, which consequently may provide a reservoir of ExPEC for acquisition by humans.
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Affiliation(s)
- J R Johnson
- VA Medical Center and Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55417, USA.
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Johnson JR, Russo TA, Tarr PI, Carlino U, Bilge SS, Vary JC, Stell AL. Molecular epidemiological and phylogenetic associations of two novel putative virulence genes, iha and iroN(E. coli), among Escherichia coli isolates from patients with urosepsis. Infect Immun 2000; 68:3040-7. [PMID: 10769012 PMCID: PMC97527 DOI: 10.1128/iai.68.5.3040-3047.2000] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two novel putative Escherichia coli virulence genes, iha and iroN from E. coli (iroN(E. coli)), were detected in 55 and 39%, respectively, of 67 E. coli isolates from patients with urosepsis. iha and iroN(E. coli) exhibited divergent associations with other putative virulence genes, phylogenetic markers, host characteristics, and antimicrobial resistance.
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Affiliation(s)
- J R Johnson
- Medical Service, VA Medical Center, and Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55417, USA.
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Johnson JR, Stell AL, Scheutz F, O'Bryan TT, Russo TA, Carlino UB, Fasching C, Kavle J, Van Dijk L, Gaastra W. Analysis of the F antigen-specific papA alleles of extraintestinal pathogenic Escherichia coli using a novel multiplex PCR-based assay. Infect Immun 2000; 68:1587-99. [PMID: 10678978 PMCID: PMC97319 DOI: 10.1128/iai.68.3.1587-1599.2000] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/1999] [Accepted: 12/15/1999] [Indexed: 11/20/2022] Open
Abstract
Polymorphisms in PapA, the major structural subunit and antigenic determinant of P fimbriae of extraintestinal pathogenic Escherichia coli, are of considerable epidemiological, phylogenetic, and immunotherapeutic importance. However, to date, no method other than DNA sequencing has been generally available for their detection. In the present study, we developed and rigorously validated a novel PCR-based assay for the 11 recognized variants of papA and then used the new assay to assess the prevalence, phylogenetic distribution, and bacteriological associations of the papA alleles among 75 E. coli isolates from patients with urosepsis. In comparison with conventional F serotyping, the assay was extremely sensitive and specific, evidence that papA sequences are highly conserved within each of the traditionally recognized F serotypes despite the diversity observed among F types. In certain strains, the assay detected serologically occult copies of papA, of which some were shown to represent false-negative serological results and others were shown to represent the presence of nonfunctional pap fragments. Among the urosepsis isolates, the assay revealed considerable segregation of papA alleles according to O:K:H serotype, consistent with vertical transmission within clones, but with exceptions which strongly suggested horizontal transfer of papA alleles between lineages. Sequencing of papA from two strains that were papA positive by probe and PCR but F negative in the new PCR assay led to the discovery of two novel papA variants, one of which was actually more prevalent among the urosepsis isolates than were several of the known papA alleles. These findings provide novel insights into the papA alleles of extraintestinal pathogenic E. coli and indicate that the F PCR assay represents a versatile new molecular tool for epidemiological and phylogenetic investigations which should make rapid, specific detection of papA alleles available to any laboratory with PCR capability.
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Affiliation(s)
- J R Johnson
- Medical Service, VA Medical Center, and Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA.
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Boyce JD, Chung JY, Adler B. Genetic organisation of the capsule biosynthetic locus of Pasteurella multocida M1404 (B:2). Vet Microbiol 2000; 72:121-34. [PMID: 10699509 DOI: 10.1016/s0378-1135(99)00193-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Capsules from a range of bacterial species have been shown to be major virulence determinants and capsule has been implicated in virulence in Pasteurella multocida. Moreover, capsular serogroup appears to be related to disease predilection. Haemorrhagic septicaemia strains belong to serogroup B and E, fowl cholera strains to serogroup A and atrophic rhinitis strains to serogroup D. The entire capsule biosynthetic locus of P. multocida A:1 has been cloned and its nucleotide sequence determined (Chung et al., 1998. FEMS Microbiol. Lett. 166, 289-296); however, nothing is known of the P. multocida B:2 capsule locus. In this work we have determined the nucleotide sequence and genetic organisation of the P. multocida M1404 (B:2) capsule locus. By analogy with the cap loci of other bacteria, the nucleotide sequence can be divided into three functional regions. Regions 1 and 3 comprise six genes involved in transport of the polysaccharide capsule to the cell surface. The deduced products of these genes show high similarity to proteins involved in capsule export in other bacteria. Region 2 comprises nine genes which are likely involved in biosynthesis of the polysaccharide capsule. The deduced products of three of these genes (bcbA, bcbB and bcbC) show significant similarity to proteins known to be involved in polysaccharide biosynthesis while the other six show no similarity to known proteins. However, their organisation indicates they are co-transcribed with bcbA, bcbB, bcbC and the Region 1 capsule export genes, suggesting strongly that they are also involved in capsule biosynthesis.
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Affiliation(s)
- J D Boyce
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
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Clarke BR, Pearce R, Roberts IS. Genetic organization of the Escherichia coli K10 capsule gene cluster: identification and characterization of two conserved regions in group III capsule gene clusters encoding polysaccharide transport functions. J Bacteriol 1999; 181:2279-85. [PMID: 10094710 PMCID: PMC93645 DOI: 10.1128/jb.181.7.2279-2285.1999] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Analysis of the Escherichia coli K10 capsule gene cluster identified two regions, regions 1 and 3, conserved between different group III capsule gene clusters. Region 1 encodes homologues of KpsD, KpsM, KpsT, and KpsE proteins, and region 3 encodes homologues of the KpsC and KpsS proteins. An rfaH mutation abolished K10 capsule production, suggesting that expression of the K10 capsule was regulated by RfaH in a manner analogous to group II capsule gene clusters. An IS3 element and a phiR73-like prophage, both of which may have played a role in the acquisition of group III capsule gene clusters, were detected flanking the K10 capsule genes.
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Affiliation(s)
- B R Clarke
- School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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34
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Abstract
Many Escherichia coli strains are covered in a layer of surface-associated polysaccharide called the capsule. Capsular polysaccharides represent a major surface antigen, the K antigen, and more than 80 distinct K serotypes result from structural diversity in these polymers. However, not all capsules consist of K antigen. Some are due to production of an extensive layer of a polymer structurally identical to a lipopolysaccharide O antigen, but distinguished from lipopolysaccharide by the absence of terminal lipid A-core. Recent research has provided insight into the manner in which capsules are organized on the Gram-negative cell surface, the pathways used for their assembly, and the regulatory processes used to control their expression. A limited repertoire of capsule expression systems are available, despite the fact that the producing bacteria occupy a variety of ecological niches and possess diverse physiologies. All of the known capsule assembly systems seen in Gram-negative bacteria are represented in E. coli, as are the majority of the regulatory strategies. Escherichia coli therefore provides a variety of working models on which studies in other bacteria are (or can be) based. In this review, we present an overview of the current molecular and biochemical models for capsule expression in E. coli. By taking into account the organization of capsule gene clusters, details of the assembly pathway, and regulatory features that dictate capsule expression, we provide a new classification system that separates the known capsules of E. coli into four distinct groups.
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Affiliation(s)
- C Whitfield
- Department of Microbiology, University of Guelph, Ontario, Canada.
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