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Pfeifer Y, Meisinger I, Brechtel K, Gröbner S. Emergence of a multidrug-resistant Haemophilus influenzae strain causing chronic pneumonia in a patient with common variable immunodeficiency. Microb Drug Resist 2012; 19:1-5. [PMID: 23095085 DOI: 10.1089/mdr.2012.0060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We report the emergence of a multidrug-resistant Haemophilus influenzae strain in a patient with common variable immunodeficiency suffering from recurrent bronchopneumonia caused by H. influenzae. After the patient had received several antibiotic therapies, a strain was isolated showing resistance to ampicillin, ampicillin/sulbactam, cefazolin, cefuroxime, ciprofloxacin, and clarithromycin. Polymerase chain reaction analyses and sequencing revealed the presence of the beta-lactamase gene bla(TEM-1), two mutations (A502T and R517H) in the ftsI gene encoding the transpeptidase region of the penicillin-binding protein 3, and one mutation in the ribosomal protein gene L4 (G65D) conferring resistance to beta-lactams and macrolides, respectively. Additionally, the plasmid-encoded aac(6')-Ib-cr gene mediating slightly reduced susceptibility to quinolones and two mutations in the DNA gyrase gene gyrA and one mutation in the topoisomerase IV gene parC were identified leading to a high-level fluoroquinolone-resistant phenotype. In conclusion, the treatment of H. influenzae infections accompanied by high bacterial loads such as bronchopneumonia can be complicated by the selection of multidrug-resistant strains. Moreover, the emergence of aac(6')-Ib-cr in H. influenzae causing low fluoroquinolone resistance levels might have contributed to the selection of DNA gyrase and topoisomerase IV mutants.
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Affiliation(s)
- Yvonne Pfeifer
- Robert-Koch-Institute, FG13 Nosocomial Infections, Wernigerode, Germany
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Modified lipooligosaccharide structure protects nontypeable Haemophilus influenzae from IgM-mediated complement killing in experimental otitis media. mBio 2012; 3:e00079-12. [PMID: 22761391 PMCID: PMC3398534 DOI: 10.1128/mbio.00079-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative, human-restricted pathogen. Although this bacterium typically colonizes the nasopharynx in the absence of clinical symptoms, it is also one of the major pathogens causing otitis media (OM) in children. Complement represents an important aspect of the host defense against NTHi. In general, NTHi is efficiently killed by complement-mediated killing; however, various resistance mechanisms have also evolved. We measured the complement resistance of NTHi isolates isolated from the nasopharynx and the middle ear fluids of OM patients. Furthermore, we determined the molecular mechanism of NTHi complement resistance. Complement resistance was strongly increased in isolates from the middle ear, which correlated with decreased binding of IgM. We identified a crucial role for the R2866_0112 gene in complement resistance. Deletion of this gene altered the lipooligosaccharide (LOS) composition of the bacterium, which increased IgM binding and complement-mediated lysis. In a novel mouse model of coinfection with influenza virus, we demonstrate decreased virulence for the R2866_0112 deletion mutant. These findings identify a mechanism by which NTHi modifies its LOS structure to prevent recognition by IgM and activation of complement. Importantly, this mechanism plays a crucial role in the ability of NTHi to cause OM. Nontypeable Haemophilus influenzae (NTHi) colonizes the nasopharynx of especially young children without any obvious symptoms. However, NTHi is also a major pathogen in otitis media (OM), one of the most common childhood infections. Although this pathogen is often associated with OM, the mechanism by which this bacterium is able to cause OM is largely unknown. Our study addresses a key biological question that is highly relevant for child health: what is the molecular mechanism that enables NTHi to cause OM? We show that isolates collected from the middle ear fluid exhibit increased complement resistance and that the lipooligosaccharide (LOS) structure determines IgM binding and complement activation. Modification of the LOS structure decreased NTHi virulence in a novel NTHi-influenza A virus coinfection OM mouse model. Our findings may also have important implications for other Gram-negative pathogens harboring LOS, such as Neisseria meningitidis, Moraxella catarrhalis, and Bordetella pertussis.
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Barthel D, Singh B, Riesbeck K, Zipfel PF. Haemophilus influenzae uses the surface protein E to acquire human plasminogen and to evade innate immunity. THE JOURNAL OF IMMUNOLOGY 2011; 188:379-85. [PMID: 22124123 DOI: 10.4049/jimmunol.1101927] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Pathogenic microbes acquire the human plasma protein plasminogen to their surface. In this article, we characterize binding of this important coagulation regulator to the respiratory pathogen nontypeable Haemophilus influenzae and identify the Haemophilus surface protein E (PE) as a new plasminogen-binding protein. Plasminogen binds dose dependently to intact bacteria and to purified PE. The plasminogen-PE interaction is mediated by lysine residues and is also affected by ionic strength. The H. influenzae PE knockout strain (nontypeable H. influenzae 3655Δpe) bound plasminogen with ∼65% lower intensity as compared with the wild-type, PE-expressing strain. In addition, PE expressed ectopically on the surface of Escherichia coli also bound plasminogen. Plasminogen, either attached to intact H. influenzae or bound to PE, was accessible for urokinase plasminogen activator. The converted active plasmin cleaved the synthetic substrate S-2251, and the natural substrates fibrinogen and C3b. Using synthetic peptides that cover the complete sequence of the PE protein, the major plasminogen-binding region was localized to a linear 28-aa-long N-terminal peptide, which represents aa 41-68. PE binds plasminogen and also vitronectin, and the two human plasma proteins compete for PE binding. Thus, PE is a major plasminogen-binding protein of the Gram-negative bacterium H. influenzae, and when converted to plasmin, PE-bound plasmin aids in immune evasion and contributes to bacterial virulence.
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Affiliation(s)
- Diana Barthel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology-Hans-Knöll-Institute, Jena, Germany
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Martí-Lliteras P, López-Gómez A, Mauro S, Hood DW, Viadas C, Calatayud L, Morey P, Servin A, Liñares J, Oliver A, Bengoechea JA, Garmendia J. Nontypable Haemophilus influenzae displays a prevalent surface structure molecular pattern in clinical isolates. PLoS One 2011; 6:e21133. [PMID: 21698169 PMCID: PMC3116884 DOI: 10.1371/journal.pone.0021133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 05/20/2011] [Indexed: 11/22/2022] Open
Abstract
Non-typable Haemophilus influenzae (NTHi) is a Gram negative pathogen that causes acute respiratory infections and is associated with the progression of chronic respiratory diseases. Previous studies have established the existence of a remarkable genetic variability among NTHi strains. In this study we show that, in spite of a high level of genetic heterogeneity, NTHi clinical isolates display a prevalent molecular feature, which could confer fitness during infectious processes. A total of 111 non-isogenic NTHi strains from an identical number of patients, isolated in two distinct geographical locations in the same period of time, were used to analyse nine genes encoding bacterial surface molecules, and revealed the existence of one highly prevalent molecular pattern (lgtF+, lic2A+, lic1D+, lic3A+, lic3B+, siaA−, lic2C+, ompP5+, oapA+) displayed by 94.6% of isolates. Such a genetic profile was associated with a higher bacterial resistance to serum mediated killing and enhanced adherence to human respiratory epithelial cells.
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Affiliation(s)
- Pau Martí-Lliteras
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
| | - Antonio López-Gómez
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
| | - Silvia Mauro
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
| | - Derek W. Hood
- Molecular Infectious Diseases Group, Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Headington, Oxford, United Kingdom
| | - Cristina Viadas
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
| | - Laura Calatayud
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
- Servicio de Microbiología, Hospital Universitario Bellvitge, Barcelona, Spain
- Instituto de Investigación Biomédica de Bellvitge (IDIBELL), Barcelona, Spain
- Universidad de Barcelona, Barcelona, Spain
| | - Pau Morey
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
| | - Alain Servin
- INSERM, UMR 756, Signalisation and Physiopathology of Epithelial cells, Paris, France
| | - Josefina Liñares
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
- Servicio de Microbiología, Hospital Universitario Bellvitge, Barcelona, Spain
- Instituto de Investigación Biomédica de Bellvitge (IDIBELL), Barcelona, Spain
- Universidad de Barcelona, Barcelona, Spain
| | - Antonio Oliver
- Servicio de Microbiología, Hospital Universitario Son Espases, Palma Mallorca, Spain
| | - José Antonio Bengoechea
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
- Consejo Superior de Investigaciones Científicas-CSIC, Madrid, Spain
| | - Junkal Garmendia
- Programa de Infección e Inmunidad, Fundación Caubet-CIMERA, Bunyola, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias-CIBERES, Vitoria, Spain
- Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra-Gobierno de Navarra, Mutilva, Spain
- * E-mail:
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Singh B, Jalalvand F, Mörgelin M, Zipfel P, Blom AM, Riesbeck K. Haemophilus influenzae protein E recognizes the C-terminal domain of vitronectin and modulates the membrane attack complex. Mol Microbiol 2011; 81:80-98. [PMID: 21542857 DOI: 10.1111/j.1365-2958.2011.07678.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Haemophilus influenzae protein E (PE) is a 16 kDa adhesin that induces a pro-inflammatory immune response in lung epithelial cells. The active epithelial binding region comprising amino acids PE 84-108 also interferes with complement-mediated bacterial killing by capturing vitronectin (Vn) that prevents complement deposition and formation of the membrane attack complex (MAC). Here, the interaction between PE and Vn was characterized using site-directed mutagenesis. Protein E variants were produced both in soluble forms and in surface-expressed molecules on Escherichia coli. Mutations within PE(84-108) in the full-length molecule revealed that K85 and R86 residues were important for the Vn binding. Bactericidal activity against H. influenzae was higher in human serum pre-treated with full-length PE as compared with serum incubated with PE(K85E, R86D) , suggesting that PE quenched Vn. A series of truncated Vn molecules revealed that the C-terminal domain comprising Vn(353-363) harboured the major binding region for PE. Interestingly, MAC deposition was significantly higher on mutants devoid of PE due to a decreased Vn-binding capacity when compared with wild-type H. influenzae. Our results define a fine-tuned interaction between H. influenzae and the innate immune system, and identify the mode of control of the MAC that is important for pathogen complement evasion.
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Affiliation(s)
- Birendra Singh
- Medical Microbiology and Medical Protein Chemistry, Department of Laboratory Medicine Malmö, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden
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ArcA-regulated glycosyltransferase lic2B promotes complement evasion and pathogenesis of nontypeable Haemophilus influenzae. Infect Immun 2011; 79:1971-83. [PMID: 21357723 DOI: 10.1128/iai.01269-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Signaling mechanisms used by Haemophilus influenzae to adapt to conditions it encounters during stages of infection and pathogenesis are not well understood. The ArcAB two-component signal transduction system controls gene expression in response to respiratory conditions of growth and contributes to resistance to bactericidal effects of serum and to bloodstream infection by H. influenzae. We show that ArcA of nontypeable H. influenzae (NTHI) activates expression of a glycosyltransferase gene, lic2B. Structural comparison of the lipooligosaccharide (LOS) of a lic2B mutant to that of the wild-type strain NT127 revealed that lic2B is required for addition of a galactose residue to the LOS outer core. The lic2B gene was crucial for optimal survival of NTHI in a mouse model of bacteremia and for evasion of serum complement. The results demonstrate that ArcA, which controls cellular metabolism in response to environmental reduction and oxidation (redox) conditions, also coordinately controls genes that are critical for immune evasion, providing evidence that NTHI integrates redox signals to regulate specific countermeasures against host defense.
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Unal CM, Schaar V, Riesbeck K. Bacterial outer membrane vesicles in disease and preventive medicine. Semin Immunopathol 2010; 33:395-408. [PMID: 21153593 DOI: 10.1007/s00281-010-0231-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 11/18/2010] [Indexed: 01/26/2023]
Abstract
Gram-negative bacteria have the ability to produce outer membrane-derived vesicles (OMVs) that are released into the extracellular milieu. Even though this intriguing phenomenon is well-known since many years, various aspects of bacterial OMVs are not fully described and are still in the process of being characterized in detail. One major reason for this is that depending on the bacterial species and its respective ecological niche, OMVs exhibit an enormous functional diversity. Research of the past years has clearly shown that OMVs of many pathogenic bacteria contribute to the virulence potential by enriching virulence factors and delivering them over long distances, superseding direct bacterial contact with their host. The subsequent interaction of OMVs with the host can occur at different levels regarding the type of immune response or the target cell type and may lead to different outcomes ranging from non-immunogenic activation or a pro-inflammatory response to cytotoxicity. In contrast to being virulence factors, OMVs are used for vaccination purposes in the combat against bacterial pathogens, and recent research thus is focused on to indirectly aim these versatile bacterial weapons against themselves.
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Affiliation(s)
- Can M Unal
- Medical Microbiology, Department of Laboratory Medicine Malmö, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden
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