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Mediati DG, Blair TA, Costas A, Monahan LG, Söderström B, Charles IG, Duggin IG. Genetic requirements for uropathogenic E. coli proliferation in the bladder cell infection cycle. mSystems 2024:e0038724. [PMID: 39287381 DOI: 10.1128/msystems.00387-24] [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: 03/19/2024] [Accepted: 08/09/2024] [Indexed: 09/19/2024] Open
Abstract
Uropathogenic Escherichia coli (UPEC) requires an adaptable physiology to survive the wide range of environments experienced in the host, including gut and urinary tract surfaces. To identify UPEC genes required during intracellular infection, we developed a transposon-directed insertion-site sequencing approach for cellular infection models and searched for genes in a library of ~20,000 UTI89 transposon-insertion mutants that are specifically required at the distinct stages of infection of cultured bladder epithelial cells. Some of the bacterial functional requirements apparent in host bladder cell growth overlapped with those for M9-glycerol, notably nutrient utilization, polysaccharide and macromolecule precursor biosynthesis, and cell envelope stress tolerance. Two genes implicated in the intracellular bladder cell infection stage were confirmed through independent gene deletion studies: neuC (sialic acid capsule biosynthesis) and hisF (histidine biosynthesis). Distinct sets of UPEC genes were also implicated in bacterial dispersal, where UPEC erupts from bladder cells in highly filamentous or motile forms upon exposure to human urine, and during recovery from infection in a rich medium. We confirm that the dedD gene linked to septal peptidoglycan remodeling is required during UPEC dispersal from human bladder cells and may help stabilize cell division or the cell wall during envelope stress created by host cells. Our findings support a view that the host intracellular environment and infection cycle are multi-nutrient limited and create stress that demands an array of biosynthetic, cell envelope integrity, and biofilm-related functions of UPEC. IMPORTANCE Urinary tract infections (UTIs) are one of the most frequent infections worldwide. Uropathogenic Escherichia coli (UPEC), which accounts for ~80% of UTIs, must rapidly adapt to highly variable host environments, such as the gut, bladder sub-surface, and urine. In this study, we searched for UPEC genes required for bacterial growth and survival throughout the cellular infection cycle. Genes required for de novo synthesis of biomolecules and cell envelope integrity appeared to be important, and other genes were also implicated in bacterial dispersal and recovery from infection of cultured bladder cells. With further studies of individual gene function, their potential as therapeutic targets may be realized. This study expands knowledge of the UTI cycle and establishes an approach to genome-wide functional analyses of stage-resolved microbial infections.
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Affiliation(s)
- Daniel G Mediati
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Tamika A Blair
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Ariana Costas
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
- Institut Cochin, INSERM U1016, Université de Paris, Paris, France
| | - Leigh G Monahan
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Bill Söderström
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
| | - Ian G Charles
- Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Iain G Duggin
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia
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2
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Arredondo-Alonso S, Blundell-Hunter G, Fu Z, Gladstone RA, Fillol-Salom A, Loraine J, Cloutman-Green E, Johnsen PJ, Samuelsen Ø, Pöntinen AK, Cléon F, Chavez-Bueno S, De la Cruz MA, Ares MA, Vongsouvath M, Chmielarczyk A, Horner C, Klein N, McNally A, Reis JN, Penadés JR, Thomson NR, Corander J, Taylor PW, McCarthy AJ. Evolutionary and functional history of the Escherichia coli K1 capsule. Nat Commun 2023; 14:3294. [PMID: 37322051 PMCID: PMC10272209 DOI: 10.1038/s41467-023-39052-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/26/2023] [Indexed: 06/17/2023] Open
Abstract
Escherichia coli is a leading cause of invasive bacterial infections in humans. Capsule polysaccharide has an important role in bacterial pathogenesis, and the K1 capsule has been firmly established as one of the most potent capsule types in E. coli through its association with severe infections. However, little is known about its distribution, evolution and functions across the E. coli phylogeny, which is fundamental to elucidating its role in the expansion of successful lineages. Using systematic surveys of invasive E. coli isolates, we show that the K1-cps locus is present in a quarter of bloodstream infection isolates and has emerged in at least four different extraintestinal pathogenic E. coli (ExPEC) phylogroups independently in the last 500 years. Phenotypic assessment demonstrates that K1 capsule synthesis enhances E. coli survival in human serum independent of genetic background, and that therapeutic targeting of the K1 capsule re-sensitizes E. coli from distinct genetic backgrounds to human serum. Our study highlights that assessing the evolutionary and functional properties of bacterial virulence factors at population levels is important to better monitor and predict the emergence of virulent clones, and to also inform therapies and preventive medicine to effectively control bacterial infections whilst significantly lowering antibiotic usage.
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Affiliation(s)
- Sergio Arredondo-Alonso
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | | | - Zuyi Fu
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Rebecca A Gladstone
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
| | - Alfred Fillol-Salom
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | | | - Elaine Cloutman-Green
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Pål J Johnsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ørjan Samuelsen
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Anna K Pöntinen
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - François Cléon
- Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Susana Chavez-Bueno
- University of Missouri Kansas City, Kansas City, USA
- Division of Infectious Diseases, Children's Mercy Hospital Kansas City, UMKC School of Medicine, Kansas City, USA
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Agnieszka Chmielarczyk
- Faculty of Medicine, Chair of Microbiology, Jagiellonian University Medical College, Czysta str. 18, 31-121, Kraków, Poland
| | - Carolyne Horner
- British Society for Antimicrobial Chemotherapy, Birmingham, UK
| | - Nigel Klein
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Joice N Reis
- Laboratory of Pathology and Molecular Biology (LPBM), Gonçalo Moniz Research Institute, Oswaldo Cruz Foundation, Salvador, Brazil
- Faculdade de Farmácia, Universidade Federal da Bahia, Salvador, Brazil
| | - José R Penadés
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK
| | - Nicholas R Thomson
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Jukka Corander
- Department of Biostatistics, University of Oslo, 0317, Oslo, Norway.
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK.
- Helsinki Institute of Information Technology, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland.
| | - Peter W Taylor
- School of Pharmacy, University College London, London, UK.
| | - Alex J McCarthy
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Imperial College London, London, UK.
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Naini A, Bartetzko MP, Sanapala SR, Broecker F, Wirtz V, Lisboa MP, Parameswarappa SG, Knopp D, Przygodda J, Hakelberg M, Pan R, Patel A, Chorro L, Illenberger A, Ponce C, Kodali S, Lypowy J, Anderson AS, Donald RGK, von Bonin A, Pereira CL. Semisynthetic Glycoconjugate Vaccine Candidates against Escherichia coli O25B Induce Functional IgG Antibodies in Mice. JACS AU 2022; 2:2135-2151. [PMID: 36186572 PMCID: PMC9516715 DOI: 10.1021/jacsau.2c00401] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 06/01/2023]
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is a major health concern due to emerging antibiotic resistance. Along with O1A, O2, and O6A, E. coli O25B is a major serotype within the ExPEC group, which expresses a unique O-antigen. Clinical studies with a glycoconjugate vaccine of the above-mentioned O-types revealed O25B as the least immunogenic component, inducing relatively weak IgG titers. To evaluate the immunological properties of semisynthetic glycoconjugate vaccine candidates against E. coli O25B, we here report the chemical synthesis of an initial set of five O25B glycan antigens differing in length, from one to three repeat units, and frameshifts of the repeat unit. The oligosaccharide antigens were conjugated to the carrier protein CRM197. The resulting semisynthetic glycoconjugates induced functional IgG antibodies in mice with opsonophagocytic activity against E. coli O25B. Three of the oligosaccharide-CRM197 conjugates elicited functional IgGs in the same order of magnitude as a conventional CRM197 glycoconjugate prepared with native O25B O-antigen and therefore represent promising vaccine candidates for further investigation. Binding studies with two monoclonal antibodies (mAbs) revealed nanomolar anti-O25B IgG responses with nanomolar K D values and with varying binding epitopes. The immunogenicity and mAb binding data now allow for the rational design of additional synthetic antigens for future preclinical studies, with expected further improvements in the functional antibody responses. Moreover, acetylation of a rhamnose residue was shown to be likely dispensable for immunogenicity, as a deacylated antigen was able to elicit strong functional IgG responses. Our findings strongly support the feasibility of a semisynthetic glycoconjugate vaccine against E. coli O25B.
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Affiliation(s)
- Arun Naini
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Max Peter Bartetzko
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Someswara Rao Sanapala
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Felix Broecker
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Victoria Wirtz
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Marilda P. Lisboa
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | | | - Daniel Knopp
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Jessica Przygodda
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Matthias Hakelberg
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Rosalind Pan
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Axay Patel
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Laurent Chorro
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Arthur Illenberger
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Christopher Ponce
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Srinivas Kodali
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Jacqueline Lypowy
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | | | - Robert G. K. Donald
- Pfizer
Vaccine Research and Development, Pearl River, New York 10965, United States
| | - Arne von Bonin
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
| | - Claney L. Pereira
- Vaxxilon
Deutschland GmbH, Part of Idorsia Pharmaceuticals Ltd., Magnusstr. 11, 12489 Berlin, Germany
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4
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Astley DJ, Spang L, Parnian F, Vollmerhausen T, Kilic H, Hora M, Gundogdu A, Katouli M. A comparative study of the clonal diversity and virulence characteristics of uropathogenic Escherichia coli isolated from Australian and Turkish (Turkey) children and adults with urinary tract infections. Germs 2022; 12:214-230. [PMID: 36504619 PMCID: PMC9719378 DOI: 10.18683/germs.2022.1324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/30/2022] [Accepted: 05/20/2022] [Indexed: 12/15/2022]
Abstract
Introduction The virulence-associated gene (VAG) repertoire and clonal organization of uropathogenic Escherichia coli (UPEC) strains is influenced by host demographic, geographic locale, and the setting of urinary tract infection (UTI). Nevertheless, a direct comparison of these features among Australian and Turkish UPEC remains unexplored. Accordingly, this study investigated the clonal composition and virulence characteristics of a collection of UPEC isolated from Australian and Turkish UTI patients. Methods A total of 715 UPEC strains isolated from Australian (n=361) and Turkish (n=354) children and adults with hospital (HA)- and community-acquired (CA)-UTIs were included in this study. Typing of the strains using RAPD-PCR and PhPlate fingerprinting grouped all strains into 25 clonal groups (CGs). CG representatives were phylogrouped and screened for the presence of 18 VAGs associated with extraintestinal pathogenic E. coli. Results Turkish UPEC strains were characterized by high clonal diversity and predominance of the phylogroup D, while few distinct clonal groups with phylogenetic group B2 backgrounds dominated among the Australian strains. Twelve identical CGs were shared between ≥1 patient group from either country. Australian strains, particularly those isolated from children with HA-UTI, showed higher virulence potential than their Turkish counterparts, carrying significantly more genes associated with adhesion, iron acquisition and capsule biosynthesis. Conclusions This study identified identical CGs of UPEC causing HA- and CA-UTIs among Australian and Turkish UTI patients. These CGs frequently carried VAGs associated with adhesion, iron acquisition, immune evasion, and toxin production, which may contribute to their ability to disseminate internationally and to cause UTI.
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Affiliation(s)
- Dylan John Astley
- BSc, School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC 4558, Queensland, Australia
| | - Labolina Spang
- BSc, School of Science, Technology and Engineering; University of the Sunshine Coast, Maroochydore DC 4558, Queensland, Australia
| | - Fatemeh Parnian
- BSc, School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC 4558, Queensland, Australia
| | - Tara Vollmerhausen
- PhD, School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore DC 4558, Queensland, Australia
| | - Huseyin Kilic
- PhD, Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Erciyes University, Kayseri 38039, Turkey
| | - Mehmet Hora
- PhD, Genome and Stem Cell Center (GenKok), Erciyes University, Kayseri, Turkey
| | - Aycan Gundogdu
- PhD, Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Erciyes University, Turkey and Genome and Stem Cell Center (GenKok), Erciyes University, Kayseri 38039, Turkey
| | - Mohammad Katouli
- PhD, School of Science, Technology and Engineering and Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore DC 4558, Queensland, Australia,Corresponding author: Mohammad Katouli,
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5
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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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Bile salts regulate zinc uptake and capsule synthesis in a mastitis-associated extraintestinal pathogenic Escherichia coli strain. Infect Immun 2021; 89:e0035721. [PMID: 34228495 DOI: 10.1128/iai.00357-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) are major causes of urinary and bloodstream infections. ExPEC reservoirs are not completely understood. Some mastitis-associated E. coli (MAEC) strains carry genes associated with ExPEC virulence, including metal scavenging, immune avoidance, and host attachment functions. In this study, we investigated the role of the high-affinity zinc uptake (znuABC) system in the MAEC strain M12. Elimination of znuABC moderately decreased fitness during mouse mammary gland infections. The ΔznuABC mutant strain exhibited an unexpected growth delay in the presence of bile salts, which was alleviated by the addition of excess zinc. We isolated ΔznuABC mutant suppressor mutants with improved growth of in bile salts, several of which no longer produced the K96 capsule made by strain M12. Addition of bile salts also reduced capsule production by strain M12 and ExPEC strain CP9, suggesting that capsule synthesis may be detrimental when bile salts are present. To better understand the role of the capsule, we compared the virulence of mastitis strain M12 with its unencapsulated ΔkpsCS mutant in two models of ExPEC disease. The wild type strain successfully colonized mouse bladders and kidneys and was highly virulent in intraperitoneal infections. Conversely, the ΔkpsCS mutant was unable to colonize kidneys and was unable to cause sepsis. These results demonstrate that some MAEC may be capable of causing human ExPEC illness. Virulence of strain M12 in these infections is dependent on its capsule. However, capsule may interfere with zinc homeostasis in the presence of bile salts while in the digestive tract.
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7
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Alhede M, Lorenz M, Fritz BG, Jensen PØ, Ring HC, Bay L, Bjarnsholt T. Bacterial aggregate size determines phagocytosis efficiency of polymorphonuclear leukocytes. Med Microbiol Immunol 2020; 209:669-680. [PMID: 32880037 PMCID: PMC7568703 DOI: 10.1007/s00430-020-00691-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023]
Abstract
The ability of bacteria to aggregate and form biofilms impairs phagocytosis by polymorphonuclear leukocytes (PMNs). The aim of this study was to examine if the size of aggregates is critical for successful phagocytosis and how bacterial biofilms evade phagocytosis. We investigated the live interaction between PMNs and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Staphylococcus epidermidis using confocal scanning laser microscopy. Aggregate size significantly affected phagocytosis outcome and larger aggregates were less likely to be phagocytized. Aggregates of S. epidermidis were also less likely to be phagocytized than equally-sized aggregates of the other three species. We found that only aggregates of approx. 5 μm diameter or smaller were consistently phagocytosed. We demonstrate that planktonic and aggregated cells of all four species significantly reduced the viability of PMNs after 4 h of incubation. Our results indicate that larger bacterial aggregates are less likely to be phagocytosed by PMNs and we propose that, if the aggregates become too large, circulating PMNs may not be able to phagocytose them quickly enough, which may lead to chronic infection.
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Affiliation(s)
- Maria Alhede
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Melanie Lorenz
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Blaine Gabriel Fritz
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark.,Department of Clinical Microbiology, Rigshospitalet, Afsnit 9301, Juliane Maries Vej 22, DK-2100, Copenhagen Ø, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, 2100, Copenhagen, Denmark
| | - Hans Christian Ring
- Department of Dermatology, Bispebjerg Hospital, Nielsine Nielsens Vej 9, København, NV, Denmark
| | - Lene Bay
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen, Denmark. .,Department of Clinical Microbiology, Rigshospitalet, Afsnit 9301, Juliane Maries Vej 22, DK-2100, Copenhagen Ø, Denmark.
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Khani MH, Bagheri M, Zahmatkesh A, Aghaiypour K, Mirjalili A. Effect of flagellin on inhibition of infectious mechanisms by activating opsonization and salmonella flagellum disruption. Microb Pathog 2020; 142:104057. [PMID: 32058025 DOI: 10.1016/j.micpath.2020.104057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 01/31/2023]
Abstract
Some serovars of salmonella cause huge global diseases such as enteric fever and invasive non typhoidal Salmonella disease. Flagellin as a key antigenic component of salmonella, can induce humoral and cellular immunity responses. In this research, we performed an opsonophagocytic killing assay (OPKA) as an important mechanism of the host-defense system, for salmonella to study the activity of anti-sera of native FliC, truncated modified recombinant FliC (tmFliC) and full length recombinant FliC proteins (flFliC). Also, the potency of antibodies for inhibiting bacterial movement was evaluated by traditional and newly-designed motility inhibition assay methods. Results showed both recombinant FliC anti-sera and native FliC (nFliC) anti-serum had the ability to opsonize Salmonella typhimurim, which led to bacterial clearance by mice macrophages. Also, inhibition of bacterial motility was observed for all anti-sera. Anti-nFliC and anti-flFliC sera showed higher effects on Salmonella typhimurim motility than that of tmFliC. In traditional method, about 88%, 86% and 80% inhibition were observed by using 5% nFliC, anti-flFliC and anti-tmFliC sera, respectively. In the newly-designed method using SIM (Sulfide indole motility) medium, results confirmed the traditional method for motility inhibition. Our findings suggest that salmonella fliC as a protective antigen may disrupt the flagellum apparatus activity.
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Affiliation(s)
- Mohammad-Hosein Khani
- Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Masoumeh Bagheri
- Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
| | - Azadeh Zahmatkesh
- Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Khosrow Aghaiypour
- Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ali Mirjalili
- Department of Genomics and Genetic Engineering, Razi Vaccine and Serum Research Institute (RVSRI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
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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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10
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The Role of Pseudomonas aeruginosa Lipopolysaccharide in Bacterial Pathogenesis and Physiology. Pathogens 2019; 9:pathogens9010006. [PMID: 31861540 PMCID: PMC7168646 DOI: 10.3390/pathogens9010006] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is a key molecule on the bacterial cell wall that is recognized by the host to deploy an immune defence in order to neutralize invading pathogens. However, LPS also promotes bacterial survival in a host environment by protecting the bacteria from these threats. This review explores the relationship between the different LPS glycoforms of the opportunistic pathogen Pseudomonas aeruginosa and the ability of this organism to cause persistent infections, especially in the genetic disease cystic fibrosis. We also discuss the role of LPS in facilitating biofilm formation, antibiotic resistance, and how LPS may be targeted by new antimicrobial therapies.
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Lee JH, Kim YG, Raorane CJ, Ryu SY, Shim JJ, Lee J. The anti-biofilm and anti-virulence activities of trans-resveratrol and oxyresveratrol against uropathogenic Escherichia coli. BIOFOULING 2019; 35:758-767. [PMID: 31505984 DOI: 10.1080/08927014.2019.1657418] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 08/08/2019] [Indexed: 05/25/2023]
Abstract
Uropathogenic Escherichia coli (UPEC) is the primary causative agent of urinary tract infections, which are one of the most common infectious disease types in humans. UPEC infections involve bacterial cell adhesion to bladder epithelial cells, and UPEC can also form biofilms on indwelling catheters that are often tolerant to common antibiotics. In this study, the anti-biofilm activities of t-stilbene, stilbestrol, t-resveratrol, oxyresveratrol, ε-viniferin, suffruticosol A, and vitisin A were investigated against UPEC. t-Resveratrol, oxyresveratrol, and ε-viniferin, suffruticosol A, and vitisin A significantly inhibited UPEC biofilm formation at subinhibitory concentrations (10-50 μg ml-1). These findings were supported by observations that t-resveratrol and oxyresveratrol reduced fimbriae production and the swarming motility in UPEC. Furthermore, t-resveratrol and oxyresveratrol markedly diminished the hemagglutinating ability of UPEC, and enhanced UPEC killing by human whole blood. The findings show that t-resveratrol, oxyresveratrol, and resveratrol oligomers warrant further attention as antivirulence strategies against persistent UPEC infections.
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Affiliation(s)
- Jin-Hyung Lee
- School of Chemical Engineering, Yeungnam University , Gyeongsan , Republic of Korea
| | - Yong-Guy Kim
- School of Chemical Engineering, Yeungnam University , Gyeongsan , Republic of Korea
| | | | - Shi Yong Ryu
- Department of Medicinal Chemistry, Korea Research Institute of Chemical Technology , Daejeon , Republic of Korea
| | - Jae-Jin Shim
- School of Chemical Engineering, Yeungnam University , Gyeongsan , Republic of Korea
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University , Gyeongsan , Republic of Korea
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12
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Tamadonfar KO, Omattage NS, Spaulding CN, Hultgren SJ. Reaching the End of the Line: Urinary Tract Infections. Microbiol Spectr 2019; 7:10.1128/microbiolspec.bai-0014-2019. [PMID: 31172909 PMCID: PMC11314827 DOI: 10.1128/microbiolspec.bai-0014-2019] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Indexed: 12/26/2022] Open
Abstract
Urinary tract infections (UTIs) cause a substantial health care burden. UTIs (i) are most often caused by uropathogenic Escherichia coli (UPEC), (ii) primarily affect otherwise healthy females (50% of women will have a UTI), (iii) are associated with significant morbidity and economic impact, (iv) can become chronic, and (v) are highly recurrent. A history of UTI is a significant risk factor for a recurrent UTI (rUTI). In otherwise healthy women, an acute UTI leads to a 25 to 50% chance of rUTI within months of the initial infection. Interestingly, rUTIs are commonly caused by the same strain of E. coli that led to the initial infection, arguing that there exist host-associated reservoirs, like the gastrointestinal tract and underlying bladder tissue, that can seed rUTIs. Additionally, catheter-associated UTIs (CAUTI), caused by Enterococcus and Staphylococcus as well as UPEC, represent a major health care concern. The host's response of depositing fibrinogen at the site of infection has been found to be critical to establishing CAUTI. The Drug Resistance Index, an evaluation of antibiotic resistance, indicates that UTIs have become increasingly difficult to treat since the mid-2000s. Thus, UTIs are a "canary in the coal mine," warning of the possibility of a return to the preantibiotic era, where some common infections are untreatable with available antibiotics. Numerous alternative strategies for both the prevention and treatment of UTIs are being pursued, with a focus on the development of vaccines and small-molecule inhibitors targeting virulence factors, in the hopes of reducing the burden of urogenital tract infections in an antibiotic-sparing manner.
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Affiliation(s)
- Kevin O Tamadonfar
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Natalie S Omattage
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Caitlin N Spaulding
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
- Harvard University School of Public Health, Boston, MA 02115
| | - Scott J Hultgren
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
- Center for Women's Infectious Disease Research, Washington University, School of Medicine, St. Louis, MO 63110
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13
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Blandford LE, Johnston EL, Sanderson JD, Wade WG, Lax AJ. Promoter orientation of the immunomodulatory Bacteroides fragilis capsular polysaccharide A (PSA) is off in individuals with inflammatory bowel disease (IBD). Gut Microbes 2019; 10:569-577. [PMID: 30732524 PMCID: PMC6748595 DOI: 10.1080/19490976.2018.1560755] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Bacteroides fragilis is a member of the normal microbiota of the lower gastrointestinal tract, but some strains produce the putative tumourigenic B. fragilis toxin (BFT). In addition, B. fragilis can produce multiple capsular polysaccharides that comprise a microcapsule layer, including an immunomodulatory, zwitterionic, polysaccharide A (PSA) capable of stimulating anti-inflammatory interleukin-10 (IL-10) production. It is known that the PSA promoter can undergo inversion, thereby regulating the expression of PSA. A PCR digestion technique was used to investigate B. fragilis capsular PSA promoter orientation using human samples for the first time. It was found that approximately half of the B. fragilis population in a healthy patient population had PSA orientated in the 'ON' position. However, individuals with inflammatory bowel disease (IBD) had a significantly lower percentage of the B. fragilis population with PSA orientated 'ON' in comparison with the other patient cohorts studied. Similarly, the putative tumourigenic bft-positive B. fragilis populations were significantly associated with a lower proportion of the PSA promoter orientated 'ON'. These results suggest that the proportion of the B. fragilis population with the PSA promoter 'ON' may be an indicator of gastrointestinal health.
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Affiliation(s)
| | - Emma L. Johnston
- Department of Gastroenterology, Guy’s and St. Thomas NHS Foundation Trust and King’s College London, King’s College London, London, UK
| | - Jeremy D. Sanderson
- Department of Gastroenterology, Guy’s and St. Thomas NHS Foundation Trust and King’s College London, King’s College London, London, UK
| | - William G. Wade
- King’s College London, Dental Institute, Guy’s Hospital, London, UK
| | - Alistair J. Lax
- King’s College London, Dental Institute, Guy’s Hospital, London, UK,CONTACT Alistair J. Lax King’s College London, Dental Institute, Guy’s Hospital, London
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14
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Abbanat D, Davies TA, Amsler K, He W, Fae K, Janssen S, Poolman JT, van den Dobbelsteen GPJM. Development and Qualification of an Opsonophagocytic Killing Assay To Assess Immunogenicity of a Bioconjugated Escherichia coli Vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:e00123-17. [PMID: 28971965 PMCID: PMC5717180 DOI: 10.1128/cvi.00123-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/20/2017] [Indexed: 12/16/2022]
Abstract
The global burden of disease caused by extraintestinal pathogenic Escherichia coli (ExPEC) is increasing as the prevalence of multidrug-resistant strains rises. A multivalent ExPEC O-antigen bioconjugate vaccine could have a substantial impact in preventing bacteremia and urinary tract infections. Development of an ExPEC vaccine requires a readout to assess the functionality of antibodies. We developed an opsonophagocytic killing assay (OPA) for four ExPEC serotypes (serotypes O1A, O2, O6A, and O25B) based on methods established for pneumococcal conjugate vaccines. The performance of the assay was assessed with human serum by computing the precision, linearity, trueness, total error, working range, and specificity. Serotypes O1A and O6A met the acceptance criteria for precision (coefficient of variation for repeatability and intermediate precision, ≤50%), linearity (90% confidence interval of the slope of each strain, 0.80, 1.25), trueness (relative bias range, -30% to 30%), and total error (total error range, -65% to 183%) at five serum concentrations and serotypes O2 and O25B met the acceptance criteria at four concentrations (the lowest concentration for serotypes O2 and O25B did not meet the system suitability test of maximum killing of ≥85% of E. coli cells). All serotypes met the acceptance criteria for specificity (opsonization index value reductions of ≤20% for heterologous serum preadsorption and ≥70% for homologous serum preadsorption). The assay working range was defined on the basis of the lowest and highest concentrations at which the assay jointly fulfilled the target acceptance criteria for linearity, precision, and accuracy. An OPA suitable for multiple E. coli serotypes has been developed, qualified, and used to assess the immunogenicity of a 4-valent E. coli bioconjugate vaccine (ExPEC4V) administered to humans.
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Affiliation(s)
- Darren Abbanat
- Janssen Research & Development, Raritan, New Jersey, USA
| | - Todd A Davies
- Janssen Research & Development, Raritan, New Jersey, USA
| | - Karen Amsler
- Janssen Research & Development, Raritan, New Jersey, USA
| | - Wenping He
- Janssen Research & Development, Raritan, New Jersey, USA
| | - Kellen Fae
- Janssen Vaccines & Prevention B.V., Bacterial Vaccines Discovery & Early Development, Leiden, The Netherlands
| | - Sarah Janssen
- Janssen Vaccines & Prevention B.V., Statistics & Decision Sciences, Leiden, The Netherlands
| | - Jan T Poolman
- Janssen Vaccines & Prevention B.V., Bacterial Vaccines Discovery & Early Development, Leiden, The Netherlands
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15
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Abstract
Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract and bloodstream infections and possesses an array of virulence factors for colonization, survival, and persistence. One such factor is the polysaccharide K capsule. Among the different K capsule types, the K1 serotype is strongly associated with UPEC infection. In this study, we completely sequenced the K1 UPEC urosepsis strain PA45B and employed a novel combination of a lytic K1 capsule-specific phage, saturated Tn5 transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing (TraDIS) to identify the complement of genes required for capsule production. Our analysis identified known genes involved in capsule biosynthesis, as well as two additional regulatory genes (mprA and lrhA) that we characterized at the molecular level. Mutation of mprA resulted in protection against K1 phage-mediated killing, a phenotype restored by complementation. We also identified a significantly increased unidirectional Tn5 insertion frequency upstream of the lrhA gene and showed that strong expression of LrhA induced by a constitutive Pcl promoter led to loss of capsule production. Further analysis revealed loss of MprA or overexpression of LrhA affected the transcription of capsule biosynthesis genes in PA45B and increased sensitivity to killing in whole blood. Similar phenotypes were also observed in UPEC strains UTI89 (K1) and CFT073 (K2), demonstrating that the effects were neither strain nor capsule type specific. Overall, this study defined the genome of a UPEC urosepsis isolate and identified and characterized two new regulatory factors that affect UPEC capsule production.IMPORTANCE Urinary tract infections (UTIs) are among the most common bacterial infections in humans and are primarily caused by uropathogenic Escherichia coli (UPEC). Many UPEC strains express a polysaccharide K capsule that provides protection against host innate immune factors and contributes to survival and persistence during infection. The K1 serotype is one example of a polysaccharide capsule type and is strongly associated with UPEC strains that cause UTIs, bloodstream infections, and meningitis. The number of UTIs caused by antibiotic-resistant UPEC is steadily increasing, highlighting the need to better understand factors (e.g., the capsule) that contribute to UPEC pathogenesis. This study describes the original and novel application of lytic capsule-specific phage killing, saturated Tn5 transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing to define the entire complement of genes required for capsule production in UPEC. Our comprehensive approach uncovered new genes involved in the regulation of this key virulence determinant.
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16
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Gomez-Lopez N, Romero R, Garcia-Flores V, Xu Y, Leng Y, Alhousseini A, Hassan SS, Panaitescu B. Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity. Am J Reprod Immunol 2017; 78:10.1111/aji.12723. [PMID: 28703488 PMCID: PMC5623137 DOI: 10.1111/aji.12723] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/26/2017] [Indexed: 12/23/2022] Open
Abstract
PROBLEM Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection. METHODS Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5). RESULTS (i) Intra-amniotic infection-related bacteria including cocci (eg Streptococcus agalactiae), bacilli (eg Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (eg Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; (ii) peripheral neutrophils (controls) rapidly phagocytized S. agalactiae, U. urealyticum, Gardnerella vaginalis, and Escherichia coli; (iii) amniotic fluid neutrophils rapidly phagocytized S. agalactiae and G. vaginalis; and (iv) amniotic fluid neutrophils slowly phagocytized U. urealyticum and E. coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier. CONCLUSION Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely S. agalactiae, U. urealyticum, G. vaginalis, and E. coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.
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Affiliation(s)
- Nardhy Gomez-Lopez
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
- Department of Immunology, Microbiology and Biochemistry, Wayne State University School of Medicine, Detroit, MI, USA
| | - Roberto Romero
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, University of Michigan, Ann Arbor, MI, USA
- Department of Epidemiology & Biostatistics, Michigan State University, East Lansing, MI, USA
- Center for Molecular Medicine & Genetics, Wayne State University, Detroit, MI, USA
| | - Valeria Garcia-Flores
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Yi Xu
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Yaozhu Leng
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Ali Alhousseini
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Sonia S Hassan
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Bogdan Panaitescu
- Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, & Detroit, MI, USA
- Department of Obstetrics & Gynecology, Wayne State University School of Medicine, Detroit, MI, USA
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17
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Paniagua-Contreras GL, Hernández-Jaimes T, Monroy-Pérez E, Vaca-Paniagua F, Díaz-Velásquez C, Uribe-García A, Vaca S. Comprehensive expression analysis of pathogenicity genes in uropathogenic Escherichia coli strains. Microb Pathog 2016; 103:1-7. [PMID: 27993701 DOI: 10.1016/j.micpath.2016.12.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 12/14/2016] [Accepted: 12/15/2016] [Indexed: 12/23/2022]
Abstract
In this study, we investigated distinct expression patterns of genes encoding iron-acquisition systems, adhesins, protectins, and toxins in human uroepithelial cells infected with 194 uropathogenic Escherichia coli (UPEC) strains in vitro. We assessed the association of these genes with antibiotic resistance genes in this group of UPEC strains, previously characterised by polymerase chain reaction (PCR). Strains were isolated from patients with urinary tract infections (UTIs) from Unidad Médica Familiar de Salud Pública, located in Estado de México, México. Antibiotic resistance genes were identified by PCR, and the expression of virulence genes was detected by reverse-transcriptase-PCR after in vitro infection of cultured A431 human keratinocytes derived from a vulvar epidermoid carcinoma. The most frequently expressed virulence genotypes among the investigated UPEC strains included usp (68%), iha (64.9%), kpsMT (61.3%), fim (58.2%), irp2 (48.4), papC (33.5%), set (31.4%) and astA (30.9%), whereas the most frequently detected antibiotic resistance genes were tet(A) (34%), sul1 (31.4%) and TEM (26.3%). Furthermore, the most abundant pattern of gene expression (irp2/fim/iha/kpsMT/usp), associated with 8 different combinations of antibiotic resistance genotypes, was exhibited by 28 strains (14.4%). Taken together, these results indicate collective participation of distinct virulence UPEC genotypes during in vitro infection of cultured human epithelial cells, suggesting their potential involvement in UTI pathogenesis.
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Affiliation(s)
- Gloria Luz Paniagua-Contreras
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Tania Hernández-Jaimes
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Eric Monroy-Pérez
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Felipe Vaca-Paniagua
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Clara Díaz-Velásquez
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Alina Uribe-García
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico
| | - Sergio Vaca
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Edo. de México, Mexico.
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18
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Glycolipid substrates for ABC transporters required for the assembly of bacterial cell-envelope and cell-surface glycoconjugates. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1394-1403. [PMID: 27793707 DOI: 10.1016/j.bbalip.2016.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 01/07/2023]
Abstract
Glycoconjugates, molecules that contain sugar components, are major components of the cell envelopes of bacteria and cover much of their exposed surfaces. These molecules are involved in interactions with the surrounding environment and, in pathogens, play critical roles in the interplay with the host immune system. Despite the remarkable diversity in glycoconjugate structures, most are assembled by glycosyltransferases that act on lipid acceptors at the cytosolic membrane. The resulting glycolipids are then transported to the cell surface in processes that frequently begin with ATP-binding cassette transporters. This review summarizes current understanding of the structure and biosynthesis of glycolipid substrates and the structure and functions of their transporters. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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19
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van den Dobbelsteen GPJM, Faé KC, Serroyen J, van den Nieuwenhof IM, Braun M, Haeuptle MA, Sirena D, Schneider J, Alaimo C, Lipowsky G, Gambillara-Fonck V, Wacker M, Poolman JT. Immunogenicity and safety of a tetravalent E. coli O-antigen bioconjugate vaccine in animal models. Vaccine 2016; 34:4152-4160. [PMID: 27395567 DOI: 10.1016/j.vaccine.2016.06.067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 06/10/2016] [Accepted: 06/22/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Extra-intestinal pathogenic Escherichia coli (ExPEC) are major human pathogens; however, no protective vaccine is currently available. We assessed in animal models the immunogenicity and safety of a 4-valent E. coli conjugate vaccine (ExPEC-4V, serotypes O1, O2, O6 and O25 conjugated to Exotoxin A from Pseudomonas aeruginosa (EPA)) produced using a novel in vivo bioconjugation method. METHODS Three doses of ExPEC-4V (with or without aluminum hydroxide) were administered to rabbits (2μg or 20μg per O-antigen, subcutaneously), mice (0.2μg or 2μg per O-antigen, subcutaneously) and rats (0.4μg or 4μg per O-antigen, intramuscularly). Antibody persistence and boostability were evaluated in rats using O6-EPA monovalent conjugate (0.4μg O-antigen/dose, intramuscularly). Toxicity was assessed in rats (16μg total polysaccharide, intramuscularly). Serum IgG and IgM antibodies were measured by ELISA. RESULTS Robust antigen-specific IgG responses were observed in all animal models, with increased responses in rabbits when administered with adjuvant. O antigen-specific antibody responses persisted up to 168days post-priming. Booster immunization induced a rapid recall response. Toxicity of ExPEC-4V when administered to rats was considered to be at the no observed adverse effect level. CONCLUSIONS ExPEC-4V conjugate vaccine showed good immunogenicity and tolerability in animal models supporting progression to clinical evaluation.
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Affiliation(s)
- Germie P J M van den Dobbelsteen
- Bacterial Vaccines Discovery & Early Development, Janssen Vaccines and Prevention B.V. (former Crucell Holland B.V.), Part of the Janssen Pharmaceutical Companies of Johnson and Johnson, Archimedesweg 4-6, 2333CN Leiden, The Netherlands.
| | - Kellen C Faé
- Bacterial Vaccines Discovery & Early Development, Janssen Vaccines and Prevention B.V. (former Crucell Holland B.V.), Part of the Janssen Pharmaceutical Companies of Johnson and Johnson, Archimedesweg 4-6, 2333CN Leiden, The Netherlands.
| | - Jan Serroyen
- Bacterial Vaccines Discovery & Early Development, Janssen Vaccines and Prevention B.V. (former Crucell Holland B.V.), Part of the Janssen Pharmaceutical Companies of Johnson and Johnson, Archimedesweg 4-6, 2333CN Leiden, The Netherlands.
| | - Ingrid M van den Nieuwenhof
- Bacterial Vaccines Discovery & Early Development, Janssen Vaccines and Prevention B.V. (former Crucell Holland B.V.), Part of the Janssen Pharmaceutical Companies of Johnson and Johnson, Archimedesweg 4-6, 2333CN Leiden, The Netherlands.
| | - Martin Braun
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland.
| | - Micha A Haeuptle
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland; Current address: Molecular Partners AG, Wagistrasse 14, 8952 Zürich-Schlieren, Switzerland.
| | - Dominique Sirena
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland.
| | - Joerg Schneider
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland.
| | - Cristina Alaimo
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland.
| | - Gerd Lipowsky
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland.
| | | | - Michael Wacker
- LimmaTech Biologics (former GlycoVaxyn AG), Grabenstrasse 3, 8952 Schlieren, Switzerland; Current address: Wacker Biotech Consulting, Obere Hönggerstrasse 9a, 8103 Unterengstringen, Switzerland.
| | - Jan T Poolman
- Bacterial Vaccines Discovery & Early Development, Janssen Vaccines and Prevention B.V. (former Crucell Holland B.V.), Part of the Janssen Pharmaceutical Companies of Johnson and Johnson, Archimedesweg 4-6, 2333CN Leiden, The Netherlands.
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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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Subashchandrabose S, Mobley HLT. Virulence and Fitness Determinants of Uropathogenic Escherichia coli. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0015-2012. [PMID: 26350328 PMCID: PMC4566162 DOI: 10.1128/microbiolspec.uti-0015-2012] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Indexed: 01/10/2023] Open
Abstract
Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a major global public health concern. Increasing antibiotic resistance found in clinical UPEC isolates underscores the immediate need for development of novel therapeutics against this pathogen. Better understanding of the fitness and virulence mechanisms that are integral to the pathogenesis of UTI will facilitate identification of novel strategies to prevent and treat infection with UPEC. Working towards that goal, the global UPEC research community has made great strides at unraveling various virulence and fitness genes. Here, we summarize major findings on virulence and fitness determinants that enable UPEC to successfully survive and colonize the urinary tract of mammalian hosts. Major sections of this chapter are devoted to the role of iron acquisition systems, metabolic pathways, fimbriae, flagella, toxins, biofilm formation, capsule, and strain-specific genes in the initiation and progression of UTIs. Transcriptomes of UPEC during experimental UTI in a murine model and naturally occurring UTI in women are compared to elucidate virulence mechanisms specifically involved in human UTI. Capitalizing on the advances in molecular pathogenesis research by translating these findings will help develop better clinical strategies for prevention and management of UTIs.
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Affiliation(s)
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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Lüthje P, Brauner A. Virulence factors of uropathogenic E. coli and their interaction with the host. Adv Microb Physiol 2014; 65:337-72. [PMID: 25476769 DOI: 10.1016/bs.ampbs.2014.08.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Urinary tract infections (UTIs) belong to the most common infectious diseases worldwide. The most frequently isolated pathogen from uncomplicated UTIs is Escherichia coli. To establish infection in the urinary tract, E. coli has to overcome several defence strategies of the host, including the urine flow, exfoliation of urothelial cells, endogenous antimicrobial factors and invading neutrophils. Thus, uropathogenic E. coli (UPEC) harbour a number of virulence and fitness factors enabling the bacterium to resist and overcome these different defence mechanisms. There is no particular factor which allows the identification of UPEC among the commensal faecal flora apart from the ability to enter the urinary tract and cause an infection. Many of potential virulence or fitness factors occur moreover with high redundancy. Fimbriae are inevitable for adherence to and invasion into the host cells; the type 1 pilus is an established virulence factor in UPEC and indispensable for successful infection of the urinary tract. Flagella and toxins promote bacterial dissemination, while different iron-acquisition systems allow bacterial survival in the iron-limited environment of the urinary tract. The immune response to UPEC is primarily mediated by toll-like receptors recognising lipopolysaccharide, flagella and other structures on the bacterial surface. UPEC have the capacity to subvert this immune response of the host by means of actively impacting on pro-inflammatory signalling pathways, or by physical masking of immunogenic structures. The large repertoire of bacterial virulence and fitness factors in combination with host-related differences results in a complex interaction between host and pathogen in the urinary tract.
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Affiliation(s)
- Petra Lüthje
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Annelie Brauner
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
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Role of capsule and O antigen in the virulence of uropathogenic Escherichia coli. PLoS One 2014; 9:e94786. [PMID: 24722484 PMCID: PMC3983267 DOI: 10.1371/journal.pone.0094786] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 03/19/2014] [Indexed: 01/08/2023] Open
Abstract
Urinary tract infection (UTI) is one of the most common bacterial infections in humans, with uropathogenic Escherichia coli (UPEC) the leading causative organism. UPEC has a number of virulence factors that enable it to overcome host defenses within the urinary tract and establish infection. The O antigen and the capsular polysaccharide are two such factors that provide a survival advantage to UPEC. Here we describe the application of the rpsL counter selection system to construct capsule (kpsD) and O antigen (waaL) mutants and complemented derivatives of three reference UPEC strains: CFT073 (O6:K2:H1), RS218 (O18:K1:H7) and 1177 (O1:K1:H7). We observed that while the O1, O6 and O18 antigens were required for survival in human serum, the role of the capsule was less clear and linked to O antigen type. In contrast, both the K1 and K2 capsular antigens provided a survival advantage to UPEC in whole blood. In the mouse urinary tract, mutation of the O6 antigen significantly attenuated CFT073 bladder colonization. Overall, this study contrasts the role of capsule and O antigen in three common UPEC serotypes using defined mutant and complemented strains. The combined mutagenesis-complementation strategy can be applied to study other virulence factors with complex functions both in vitro and in vivo.
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Molecular characterisation of Escherichia coli isolated from hospitalised children and adults with urinary tract infection. Eur J Clin Microbiol Infect Dis 2014; 33:975-82. [PMID: 24385002 DOI: 10.1007/s10096-013-2035-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/08/2013] [Indexed: 01/01/2023]
Abstract
Urinary tract infection (UTI) is common amongst children and recurs in 10-30 % of cases. The differences between Escherichia coli strains causing UTI among hospitalised children and adults remains to be fully elucidated. Here, we examined the genetic relatedness and virulence gene (VG) profiles of a collection of E. coli causing UTI among hospitalised children and adults. Genetic relatedness among the strains was investigated using random amplified polymorphic DNA (RAPD) analysis and the strains were characterised using a combination of phylogenetic grouping, the ability to form biofilm and the presence of antigen 43 (Ag43) and its five known alleles, as well 20 VGs associated with uropathogenic E. coli (UPEC). RAPD analysis resolved six major clusters, with two clusters (A and B) consisting almost exclusively of E. coli isolated from children. Isolates from children had a higher prevalence of alpha-haemolysin (hlyA, p < 0.05) and group II capsular polysaccharide synthesis genes (kpsMT II, p < 0.01) than adults. In contrast, E. coli strains from adults had a higher prevalence of invasive ibeA (p < 0.05) and Ag43 (agn43) (p < 0.05) genes, and produced significantly (p < 0.001) more biofilm than E. coli from children. Adult isolates also carried significantly (p < 0.05) more agn43 allele RS218 compared to isolates from children, which carried significantly (p < 0.05) more of the agn43 allele bCFT073. Our results suggest that bacterial virulence factors play an important role in UTI among hospitalised children; however, further research will determine whether these findings apply to a larger cohort and other clinical settings for UTI in children and adults.
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Wiles TJ, Norton JP, Russell CW, Dalley BK, Fischer KF, Mulvey MA. Combining quantitative genetic footprinting and trait enrichment analysis to identify fitness determinants of a bacterial pathogen. PLoS Genet 2013; 9:e1003716. [PMID: 23990803 PMCID: PMC3749937 DOI: 10.1371/journal.pgen.1003716] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 06/26/2013] [Indexed: 01/03/2023] Open
Abstract
Strains of Extraintestinal Pathogenic Escherichia c oli (ExPEC) exhibit an array of virulence strategies and are a major cause of urinary tract infections, sepsis and meningitis. Efforts to understand ExPEC pathogenesis are challenged by the high degree of genetic and phenotypic variation that exists among isolates. Determining which virulence traits are widespread and which are strain-specific will greatly benefit the design of more effective therapies. Towards this goal, we utilized a quantitative genetic footprinting technique known as transposon insertion sequencing (Tn-seq) in conjunction with comparative pathogenomics to functionally dissect the genetic repertoire of a reference ExPEC isolate. Using Tn-seq and high-throughput zebrafish infection models, we tracked changes in the abundance of ExPEC variants within saturated transposon mutant libraries following selection within distinct host niches. Nine hundred and seventy bacterial genes (18% of the genome) were found to promote pathogen fitness in either a niche-dependent or independent manner. To identify genes with the highest therapeutic and diagnostic potential, a novel Trait Enrichment Analysis (TEA) algorithm was developed to ascertain the phylogenetic distribution of candidate genes. TEA revealed that a significant portion of the 970 genes identified by Tn-seq have homologues more often contained within the genomes of ExPEC and other known pathogens, which, as suggested by the first axiom of molecular Koch's postulates, is considered to be a key feature of true virulence determinants. Three of these Tn-seq-derived pathogen-associated genes--a transcriptional repressor, a putative metalloendopeptidase toxin and a hypothetical DNA binding protein--were deleted and shown to independently affect ExPEC fitness in zebrafish and mouse models of infection. Together, the approaches and observations reported herein provide a resource for future pathogenomics-based research and highlight the diversity of factors required by a single ExPEC isolate to survive within varying host environments.
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Affiliation(s)
- Travis J. Wiles
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - J. Paul Norton
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Colin W. Russell
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Brian K. Dalley
- Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Kael F. Fischer
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- ARUP Laboratories, Salt Lake City, Utah, United States of America
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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26
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Willis LM, Whitfield C. Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways. Carbohydr Res 2013; 378:35-44. [PMID: 23746650 DOI: 10.1016/j.carres.2013.05.007] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/06/2013] [Accepted: 05/11/2013] [Indexed: 12/11/2022]
Abstract
Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.
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Affiliation(s)
- Lisa M Willis
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Xu L, Wang Q, Xiao J, Liu Q, Wang X, Chen T, Zhang Y. Characterization of Edwardsiella tarda waaL: roles in lipopolysaccharide biosynthesis, stress adaptation, and virulence toward fish. Arch Microbiol 2010; 192:1039-47. [PMID: 20938646 DOI: 10.1007/s00203-010-0635-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 08/12/2010] [Accepted: 09/23/2010] [Indexed: 12/29/2022]
Abstract
Edwardsiella tarda is the causative agent of edwardsiellosis in fish. The genome sequence of a virulent strain EIB202 has been determined. According to the genome sequence, the lipopolysaccharide (LPS) synthesis cluster containing a putative O-antigen ligase gene waaL was identified. Here, the in-frame deletion mutant ΔwaaL was constructed to analyze the function of WaaL in E. tarda EIB202. The ΔwaaL mutant displayed absence in O-antigen side chains in the LPS production. The ΔwaaL mutant exhibited an increased sensitivity to hydrogen peroxide indicating that the LPS was involved in the endurance to the oxidative stress in hosts during infection. In addition, the resistance of ΔwaaL to serum and polymyxin B decreased remarkably. The ΔwaaL mutant was also attenuated in virulence, showed an impaired ability in internalization of epithelioma papulosum cyprinid (EPC) cells and a comparatively poor ability of proliferation in vivo, which was in line with the increased LD(50) value. These results indicated that waaL gene was a functional member of the gene cluster involved in LPS synthesis and highlighted the importance of the O-antigen side chains to stress adaption and virulence in E. tarda, signifying the gene as a potential target for live attenuated vaccine against this bacterium.
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Affiliation(s)
- Lili Xu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 200237 Shanghai, People's Republic of China
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28
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Abstract
The urinary tract is among the most common sites of bacterial infection, and Escherichia coli is by far the most common species infecting this site. Individuals at high risk for symptomatic urinary tract infection (UTI) include neonates, preschool girls, sexually active women, and elderly women and men. E. coli that cause the majority of UTIs are thought to represent only a subset of the strains that colonize the colon. E. coli strains that cause UTIs are termed uropathogenic E. coli (UPEC). In general, UPEC strains differ from commensal E. coli strains in that the former possess extragenetic material, often on pathogenicity-associated islands (PAIs), which code for gene products that may contribute to bacterial pathogenesis. Some of these genes allow UPEC to express determinants that are proposed to play roles in disease. These factors include hemolysins, secreted proteins, specific lipopolysaccharide and capsule types, iron acquisition systems, and fimbrial adhesions. The current dogma of bacterial pathogenesis identifies adherence, colonization, avoidance of host defenses, and damage to host tissues as events vital for achieving bacterial virulence. These considerations, along with analysis of the E. coli CFT073, UTI89, and 536 genomes and efforts to identify novel virulence genes should advance the field significantly and allow for the development of a comprehensive model of pathogenesis for uropathogenic E. coli.Further study of the adaptive immune response to UTI will be especially critical to refine our understanding and treatment of recurrent infections and to develop vaccines.
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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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Nazareth H, Genagon SA, Russo TA. Extraintestinal pathogenic Escherichia coli survives within neutrophils. Infect Immun 2007; 75:2776-85. [PMID: 17296761 PMCID: PMC1932911 DOI: 10.1128/iai.01095-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Extracellular pathogenic Escherichia coli (ExPEC) strains are common causes of a variety of clinical syndromes, including urinary tract infections, abdominal infections, nosocomial pneumonia, neonatal meningitis, and sepsis. ExPEC strains are extracellular bacterial pathogens; therefore, the innate immune response (e.g., professional phagocytes) plays a crucial role in the host defense against them. Studies using the model ExPEC strain CP9 demonstrated that it is relatively resistant to neutrophil-mediated bactericidal activity. Although this could be due to resistance to phagocytosis, the ability of CP9 to survive the intracellular killing mechanisms of neutrophils is another possibility. Using a variation of the intracellular invasion assay, we studied the survival of CP9 within peripheral blood-derived human neutrophils. Our results indicated that CP9 did survive within human neutrophils, but we were unable to demonstrate that intracellular replication occurred. This finding was not unique to CP9, since when a conservative assessment of survival was used, four of six additional ExPEC strains, but not an E. coli laboratory strain, were also capable of survival within neutrophils. Initial studies in which we began to decipher the mechanisms by which CP9 is able to successfully survive intracellular neutrophil-mediated bactericidal activity demonstrated that CP9 was at least partially susceptible to the neutrophil oxidative burst. Therefore, absolute resistance to the oxidative burst is not a mechanism by which ExPEC survives within neutrophils. In addition, electron microscopy studies showed that CP9 appeared to be present in phagosomes within neutrophils. Therefore, avoidance of phagosomal uptake or subsequent escape from the phagosome does not appear to be a mechanism that contributes to CP9's survival. These findings suggest that survival of ExPEC within neutrophils may be an important virulence mechanism.
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Affiliation(s)
- Helen Nazareth
- Department of Medicine, Division of Infectious Diseases, 3435 Main Street, Biomedical Research Building, Room 141, Buffalo, NY 14214, USA
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31
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Abstract
Many microbial pathogens evolved to circumvent the attack of neutrophils, which are essential effector cells of the innate immune system. Here we review six major strategies that pathogenic bacteria and fungi use to evade neutrophil defences: (i) turning on survival and stress responses, (ii) avoiding contact, (iii) preventing phagocytosis, (iv) surviving intracellularly, (v) inducing cell death and (vi) evading killing by neutrophil extracellular traps. For each category we give examples and further focus on one particular pathogenic microbe in more detail. Pathogens include Candida albicans, Cryptococcus neoformans, Yersinia ssp., Helicobacter pylori, Staphylococcus aureus, Streptococcus pyogenes and Streptococcus pneumoniae.
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Affiliation(s)
- Constantin F Urban
- Department of Cellular Microbiology, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
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32
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Strauch E, Beutin L. Imprecise excision of insertion element IS5 from the fliC gene contributes to flagellar diversity in Escherichia coli. FEMS Microbiol Lett 2006; 256:195-202. [PMID: 16499606 DOI: 10.1111/j.1574-6968.2006.00100.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Motile strains of Escherichia coli K12 carrying both a chromosomal fliC-H48 gene and a plasmid encoded fliC-H4 gene express both types of flagellins, which are coassembled into functional flagella. By using flagellar-H48-specific antiserum and a plasmid curing procedure, nonmotile mutants were found that carried an IS5 insertion in the chromosomal fliC-H48 gene. Motile revertants were isolated that showed deletions of the IS5 element together with sections of the fliC-H48 gene resulting in an altered flagellar serotype in these strains. As IS5 elements were found associated with 35 of 53 known H-types in wildtype E. coli strains, this insertion element might play a major role in serotype diversity.
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Affiliation(s)
- Eckhard Strauch
- National Reference Laboratory for Escherichia coli, Department of Biological Safety, Federal Institute for Risk Assessment, Berlin, Germany
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33
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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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Kumar V, Ganguly NK, Joshi K, Mittal R, Harjai K, Chhibber S, Sharma S. Protective efficacy and immunogenicity of Escherichia coli K13 diphtheria toxoid conjugate against experimental ascending pyelonephritis. Med Microbiol Immunol 2005; 194:211-7. [PMID: 15909203 DOI: 10.1007/s00430-005-0241-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Indexed: 10/25/2022]
Abstract
In the present study, protective efficacy of Escherichia coli capsular antigen, K13, was evaluated in a mouse model of pyelonephritis. Unconjugated capsular polysaccharide failed to provide any protection. However, coupling of K13 to diphtheria toxoid (DT) enhanced its immunogenicity and led to significant production of anticapsular antibodies in mice. Immunization of animals with K13-DT conjugate also caused significant improvement in cell-mediated immune response as indicated by an increase in lymphoblastogenic response and in the CD4+/CD8+ cell ratio of splenic lymphocytes. Significant decrease in bacterial load and renal severity scores were observed in K13-DT immunized animals. Suitability of K13-DT conjugate as an effective vaccine candidate against urinary tract infections caused by E. coli has been discussed.
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Affiliation(s)
- Varinder Kumar
- Department of Microbiology, Panjab University, Basic Medical Sciences Building, Sector 14, Chandigarh, 160014, India
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35
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Schneider G, Dobrindt U, Brüggemann H, Nagy G, Janke B, Blum-Oehler G, Buchrieser C, Gottschalk G, Emödy L, Hacker J. The pathogenicity island-associated K15 capsule determinant exhibits a novel genetic structure and correlates with virulence in uropathogenic Escherichia coli strain 536. Infect Immun 2004; 72:5993-6001. [PMID: 15385503 PMCID: PMC517556 DOI: 10.1128/iai.72.10.5993-6001.2004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The K15 capsule determinant of uropathogenic Escherichia coli strain 536 (O6:K15:H31) is part of a novel 79.6-kb pathogenicity island (PAI) designated PAI V536 that is absent from the genome of nonpathogenic E. coli K-12 strain MG1655. PAI V536 shows typical characteristics of a composite PAI that is associated with the pheV tRNA gene and contains the pix fimbriae determinant as well as genes coding for a putative phosphoglycerate transport system, an autotransporter protein, and hypothetical open reading frames. A gene cluster coding for a putative general secretion pathway system, together with a kps(K15) determinant, is localized downstream of a truncated pheV gene ('pheV) also present in this chromosomal region. The distribution of genes present on PAI V536 was studied by PCR in different pathogenic and nonpathogenic E. coli isolates of various sources. Analysis of the 20-kb kps locus revealed a so far unknown genetic organization. Generally, the kps(K15) gene cluster resembles that of group 2 and 3 capsules, where two conserved regions (regions 1 and 3) are located up- or downstream of a highly variable serotype-specific region (region 2). Interestingly, recombination of a group 2 and 3 determinant may have been involved in the evolution of the K15 capsule-encoding gene cluster. Expression of the K15 capsule is important for virulence in a murine model of ascending urinary tract infection but not for serum resistance of E. coli strain 536.
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Affiliation(s)
- György Schneider
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Würzburg, Germany
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36
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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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37
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Lawrence ML, Banes MM, Azadi P, Reeks BY. The Edwardsiella ictaluri O polysaccharide biosynthesis gene cluster and the role of O polysaccharide in resistance to normal catfish serum and catfish neutrophils. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1409-1421. [PMID: 12777482 DOI: 10.1099/mic.0.26138-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Edwardsiella ictaluri, the causative agent of enteric septicaemia of catfish (ESC), expresses long O polysaccharide (OPS) chains on its surface. The authors previously reported the construction of an isogenic Ed. ictaluri OPS mutant strain and demonstrated that this strain is avirulent in channel catfish. This paper reports the cloning of the Ed. ictaluri OPS biosynthesis gene cluster and identification of the mutated gene in the OPS-negative strain. The sequenced region contains eight complete ORFs and one incomplete ORF encoding LPS biosynthesis enzymes. The mutated gene (designated wbiT) was similar to other bacterial galactose-4-epimerases. Glycosyl composition analysis indicated that wild-type Ed. ictaluri OPS contains higher amounts of galactose and N-acetylgalactosamine than the OPS mutant strain, which correlated well with predicted functions of the genes identified in the OPS biosynthesis cluster. The OPS mutant had a relatively small, but significant, decrease in its ability to survive in normal catfish serum compared to wild-type Ed. ictaluri, but it retained the ability to resist killing by catfish neutrophils.
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Affiliation(s)
- Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA
| | - Michelle M Banes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, 220 Riverbend Road, Athens, GA 30602-4712, USA
| | - Brenda Y Reeks
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762-6100, USA
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38
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Mellata M, Dho-Moulin M, Dozois CM, Curtiss R, Lehoux B, Fairbrother JM. Role of avian pathogenic Escherichia coli virulence factors in bacterial interaction with chicken heterophils and macrophages. Infect Immun 2003; 71:494-503. [PMID: 12496200 PMCID: PMC143357 DOI: 10.1128/iai.71.1.494-503.2003] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) cause extraintestinal disease in avian species via respiratory tract infection. Virulence factors associated with APEC include type 1 and P fimbriae, curli, aerobactin, lipopolysaccharide (LPS), K1 capsular antigen, temperature-sensitive hemagglutinin (Tsh), and an uncharacterized pathogen-specific chromosomal region (the 0-min region). The role of these virulence factors in bacterial interaction with phagocytes was investigated by using mutants of three APEC strains, each belonging to one of the most predominant serogroups O1, O2, and O78. Bacterial cell interaction with avian phagocytes was tested with primary cultures of chicken heterophils and macrophages. The presence of type 1 fimbriae and, in contrast, the absence of P fimbriae, K1 capsule, O78 antigen, and the 0-min region promoted bacterial association with chicken heterophils and macrophages. The presence of type 1 and P fimbriae, O78 antigen, and the 0-min region seemed to protect bacteria against the bactericidal effect of phagocytes, especially heterophils. The tested virulence factors seemed to have a limited role in intracellular survival for up to 48 h in macrophages. Generally, opsonized and nonopsonized bacteria were eliminated to the same extent, but in some cases, unopsonized bacteria were eliminated to a greater extent than opsonized bacteria. These results confirm the important role of type 1 fimbriae in promotion of initial phagocytosis, but nevertheless indicate a role for type 1 fimbriae in the protection of bacteria from subsequent killing, at least in heterophils. The results also indicate a role for K1 capsule, O78 antigen, P fimbriae, and the 0-min region in initial avoidance of phagocytosis, but demonstrate an additional role for O78 antigen, P fimbriae, and the 0-min region in subsequent protection against the bactericidal effects of phagocytes after bacterial association has occurred.
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Affiliation(s)
- Melha Mellata
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, St. Hyacinthe, Québec J2S 7C6, Canada
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