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Xiao J, Su L, Huang S, Liu L, Ali K, Chen Z. Epidemic Trends and Biofilm Formation Mechanisms of Haemophilus influenzae: Insights into Clinical Implications and Prevention Strategies. Infect Drug Resist 2023; 16:5359-5373. [PMID: 37605758 PMCID: PMC10440118 DOI: 10.2147/idr.s424468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/10/2023] [Indexed: 08/23/2023] Open
Abstract
Haemophilus influenzae (H. influenzae) is a significant pathogen responsible for causing respiratory tract infections and invasive diseases, leading to a considerable disease burden. The Haemophilus influenzae type b (Hib) conjugate vaccine has notably decreased the incidence of severe infections caused by Hib strains, and other non-typable H. influenzae (NTHi) serotypes have emerged as epidemic strains worldwide. As a result, the global epidemic trends and antibiotic resistance characteristics of H. influenzae have been altered. Researches on the virulence factors of H. influenzae, particularly the mechanisms underlying biofilm formation, and the development of anti-biofilm strategies hold significant clinical value. This article provides a summary of the epidemic trends, typing methods, virulence factors, biofilm formation mechanisms, and prevention strategies of H. influenzae. The increasing prevalence of NTHi strains and antibiotic resistance among H. influenzae, especially the high β-lactamase positivity and the emergence of BLNAR strains have increased clinical difficulties. Understanding its virulence factors, especially the formation mechanism of biofilm, and formulating effective anti-biofilm strategies may help to reduce the clinical impact. Therefore, future research efforts should focus on developing new approaches to prevent and control H. influenzae infections.
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Affiliation(s)
- Jiying Xiao
- Department of Pulmonology, Hangzhou Children’s Hospital, Hangzhou, Zhejiang, 310015, People’s Republic of China
| | - Lin Su
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310052, People’s Republic of China
- National Clinical Research Center for Child Health, National Children’s Regional Medical Center, Hangzhou, Zhejiang, 310052, People’s Republic of China
| | - Shumin Huang
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310052, People’s Republic of China
- National Clinical Research Center for Child Health, National Children’s Regional Medical Center, Hangzhou, Zhejiang, 310052, People’s Republic of China
| | - Lingyue Liu
- Department of Pulmonology, Hangzhou Children’s Hospital, Hangzhou, Zhejiang, 310015, People’s Republic of China
| | - Kamran Ali
- Department of Oncology, The Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University School of Medicine, Yiwu, Zhejiang, 322000, People’s Republic of China
| | - Zhimin Chen
- Department of Pulmonology, Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310052, People’s Republic of China
- National Clinical Research Center for Child Health, National Children’s Regional Medical Center, Hangzhou, Zhejiang, 310052, People’s Republic of China
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Balázs VL, Filep R, Répás F, Kerekes E, Szabó P, Kocsis B, Böszörményi A, Krisch J, Horváth G. Immortelle (Helichrysum italicum (Roth) G. Don) Essential Oil Showed Antibacterial and Biofilm Inhibitory Activity against Respiratory Tract Pathogens. Molecules 2022; 27:molecules27175518. [PMID: 36080283 PMCID: PMC9457731 DOI: 10.3390/molecules27175518] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022] Open
Abstract
The biofilm formation of bacteria in different parts of the human body can influence the success of antibiotic therapy. Essential oils (EOs) and their components are becoming increasingly popular in point of view of medicinal applications, because of their antibacterial efficacy. The immortelle EO has been used traditionally as an expectorant; however, there are no studies summarizing its antibacterial effect against respiratory tract bacteria. Our aim was to investigate the antibacterial and biofilm inhibitory activity of immortelle (Helichrysum italicum) EO against respiratory tract pathogens such as Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa and Streptococcus pneumoniae. In order to prove the antibacterial effect of the immortelle EO, broth microdilution and biofilm inhibition tests, and membrane damage assay were investigated. Scanning electron microscopy was used to identify the structural modifications in bacterial cells. Our results showed that immortelle EO has antibacterial and anti-biofilm effects against respiratory tract bacteria used in this study. H. parainfluenzae was the most sensitive to each treatment, however, P. aeruginosa was the most resistant bacteria. In conclusion, the studied EO may have a role in the treatment of respiratory tract infections due to their antibacterial and anti-biofilm activity.
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Affiliation(s)
- Viktória L. Balázs
- Department of Pharmacognosy, Faculty of Pharmacy, University of Pécs, 7624 Pécs, Hungary
| | - Rita Filep
- Department of Pharmacognosy, Faculty of Pharmacy, University of Pécs, 7624 Pécs, Hungary
| | - Fanni Répás
- Department of Pharmacognosy, Faculty of Pharmacy, University of Pécs, 7624 Pécs, Hungary
| | - Erika Kerekes
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary
| | - Péter Szabó
- Institute of Geography and Earth Sciences, Faculty of Sciences, University of Pécs, 7624 Pécs, Hungary
| | - Béla Kocsis
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, 7624 Pécs, Hungary
| | - Andrea Böszörményi
- Institute of Pharmacognosy, Faculty of Pharmacy, Semmelweis University, 1085 Budapest, Hungary
| | - Judit Krisch
- Department of Food Engineering, Faculty of Engineering, University of Szeged, 6724 Szeged, Hungary
| | - Györgyi Horváth
- Department of Pharmacognosy, Faculty of Pharmacy, University of Pécs, 7624 Pécs, Hungary
- Correspondence:
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Nontypeable Haemophilus influenzae infection impedes Pseudomonas aeruginosa colonization and persistence in mouse respiratory tract. Infect Immun 2021; 90:e0056821. [PMID: 34780275 DOI: 10.1128/iai.00568-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Patients with cystic fibrosis (CF) experience lifelong respiratory infections which are a significant cause of morbidity and mortality. These infections are polymicrobial in nature, and the predominant bacterial species undergo a predictable series of changes as patients age. Young patients have populations dominated by opportunists that are typically found within the microbiome of the human nasopharynx, such as nontypeable Haemophilus influenzae (NTHi); these are eventually supplanted and the population within the CF lung is later dominated by pathogens such as Pseudomonas aeruginosa (Pa). In this study, we investigated how initial colonization with NTHi impacts colonization and persistence of Pa in the respiratory tract. Analysis of polymicrobial biofilms in vitro by confocal microscopy revealed that NTHi promoted greater levels of Pa biofilm volume and diffusion. However, sequential respiratory infection of mice with NTHi followed by Pa resulted in significantly lower Pa as compared to infection with Pa alone. Coinfected mice also had reduced airway tissue damage and lower levels of inflammatory cytokines as compared with Pa infected mice. Similar results were observed after instillation of heat-inactivated NTHi bacteria or purified NTHi lipooligosaccharide (LOS) endotoxin prior to Pa introduction. Based on these results, we conclude that NTHi significantly reduces susceptibility to subsequent Pa infection, most likely due to priming of host innate immunity rather than a direct competitive interaction between species. These findings have potential significance with regard to therapeutic management of early life infections in patients with CF.
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Lukacik P, Owen CD, Harris G, Bolla JR, Picaud S, Alibay I, Nettleship JE, Bird LE, Owens RJ, Biggin PC, Filippakopoulos P, Robinson CV, Walsh MA. The structure of nontypeable Haemophilus influenzae SapA in a closed conformation reveals a constricted ligand-binding cavity and a novel RNA binding motif. PLoS One 2021; 16:e0256070. [PMID: 34653190 PMCID: PMC8519434 DOI: 10.1371/journal.pone.0256070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a significant pathogen in respiratory disease and otitis media. Important for NTHi survival, colonization and persistence in vivo is the Sap (sensitivity to antimicrobial peptides) ABC transporter system. Current models propose a direct role for Sap in heme and antimicrobial peptide (AMP) transport. Here, the crystal structure of SapA, the periplasmic component of Sap, in a closed, ligand bound conformation, is presented. Phylogenetic and cavity volume analysis predicts that the small, hydrophobic SapA central ligand binding cavity is most likely occupied by a hydrophobic di- or tri- peptide. The cavity is of insufficient volume to accommodate heme or folded AMPs. Crystal structures of SapA have identified surface interactions with heme and dsRNA. Heme binds SapA weakly (Kd 282 μM) through a surface exposed histidine, while the dsRNA is coordinated via residues which constitute part of a conserved motif (estimated Kd 4.4 μM). The RNA affinity falls within the range observed for characterized RNA/protein complexes. Overall, we describe in molecular-detail the interactions of SapA with heme and dsRNA and propose a role for SapA in the transport of di- or tri-peptides.
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Affiliation(s)
- Petra Lukacik
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - C. David Owen
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Gemma Harris
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Jani Reddy Bolla
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Sarah Picaud
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | - Irfan Alibay
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Joanne E. Nettleship
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Louise E. Bird
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Raymond J. Owens
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Philip C. Biggin
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Carol V. Robinson
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Martin A. Walsh
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, United Kingdom
- Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
- * E-mail:
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Abstract
Potassium is an essential mineral nutrient required by all living cells for normal physiological function. Therefore, maintaining intracellular potassium homeostasis during bacterial infection is a requirement for the survival of both host and pathogen. However, pathogenic bacteria require potassium transport to fulfill nutritional and chemiosmotic requirements, and potassium has been shown to directly modulate virulence gene expression, antimicrobial resistance, and biofilm formation. Host cells also require potassium to maintain fundamental biological processes, such as renal function, muscle contraction, and neuronal transmission; however, potassium flux also contributes to critical immunological and antimicrobial processes, such as cytokine production and inflammasome activation. Here, we review the role and regulation of potassium transport and signaling during infection in both mammalian and bacterial cells and highlight the importance of potassium to the success and survival of each organism.
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Haemophilin-Producing Strains of Haemophilus haemolyticus Protect Respiratory Epithelia from NTHi Colonisation and Internalisation. Pathogens 2021; 10:pathogens10010029. [PMID: 33401487 PMCID: PMC7823694 DOI: 10.3390/pathogens10010029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 11/17/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a significant respiratory tract pathogen responsible for infections that collectively pose a substantial health and socioeconomic burden. The clinical course of these infections is largely dictated by NTHi interactions with host respiratory epithelia, and thus, approaches that disrupt colonisation and invasion may have significant therapeutic potential. Survival, successful host–cell interactions, and pathogenesis are reliant on NTHi’s ability to sequester host-derived haem. Previously, we demonstrated the therapeutic potential of exploiting this haem-dependence using a closely related competitor bacterium, Haemophilus haemolyticus (Hh). Hh strains capable of producing the novel haem-binding protein haemophilin (Hpl) possessed potent inhibitory activity by restricting NTHi access to haem in a broth co-culture environment. Here, we extend this work to cell culture models that more closely represent the human respiratory epithelium and show that Hh strains with high levels of hpl expression protect epithelial cell line monolayers against adhesion and invasion by NTHi. Inhibitory activity was dependent on the level of Hpl production, which was stimulated by NTHi challenge and nasopharyngeal cell exposure. Provided these protective benefits translate to in vivo applications, Hpl-producing Hh may have probiotic utility against NTHi infections by inhibiting requisite nasopharyngeal colonisation.
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7
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Wen S, Feng D, Chen D, Yang L, Xu Z. Molecular epidemiology and evolution of Haemophilus influenzae. INFECTION GENETICS AND EVOLUTION 2020; 80:104205. [DOI: 10.1016/j.meegid.2020.104205] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 10/25/2022]
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In Vitro Anti-NTHi Activity of Haemophilin-Producing Strains of Haemophilus haemolyticus. Pathogens 2020; 9:pathogens9040243. [PMID: 32218184 PMCID: PMC7238096 DOI: 10.3390/pathogens9040243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/18/2020] [Accepted: 03/22/2020] [Indexed: 12/21/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a leading causative organism of opportunistic respiratory tract infections. However, there are currently no effective vaccination strategies, and existing treatments are compromised by antibiotic resistance. We previously characterized Haemophilus haemolyticus (Hh) strains capable of producing haemophilin (HPL), a heme-binding protein that restricts NTHi growth by limiting its access to an essential growth factor, heme. Thus, these strains may have utility as a probiotic therapy against NTHi infection by limiting colonization, migration and subsequent infection in susceptible individuals. Here, we assess the preliminary feasibility of this approach by direct in vitro competition assays between NTHi and Hh strains with varying capacity to produce HPL. Subsequent changes in NTHi growth rate and fitness, in conjunction with HPL expression analysis, were employed to assess the NTHi-inhibitory capacity of Hh strains. HPL-producing strains of Hh not only outcompeted NTHi during short-term and extended co-culture, but also demonstrated a growth advantage compared with Hh strains unable to produce the protein. Additionally, HPL expression levels during competition correlated with the NTHi-inhibitory phenotype. HPL-producing strains of Hh demonstrate significant probiotic potential against NTHi colonization in the upper respiratory tract, however, further investigations are warranted to demonstrate a range of other characteristics that would support the eventual development of a probiotic.
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9
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Latham RD, Torrado M, Atto B, Walshe JL, Wilson R, Guss JM, Mackay JP, Tristram S, Gell DA. A heme-binding protein produced by Haemophilus haemolyticus inhibits non-typeable Haemophilus influenzae. Mol Microbiol 2019; 113:381-398. [PMID: 31742788 DOI: 10.1111/mmi.14426] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 01/02/2023]
Abstract
Commensal bacteria serve as an important line of defense against colonisation by opportunisitic pathogens, but the underlying molecular mechanisms remain poorly explored. Here, we show that strains of a commensal bacterium, Haemophilus haemolyticus, make hemophilin, a heme-binding protein that inhibits growth of the opportunistic pathogen, non-typeable Haemophilus influenzae (NTHi) in culture. We purified the NTHi-inhibitory protein from H. haemolyticus and identified the hemophilin gene using proteomics and a gene knockout. An x-ray crystal structure of recombinant hemophilin shows that the protein does not belong to any of the known heme-binding protein folds, suggesting that it evolved independently. Biochemical characterisation shows that heme can be captured in the ferrous or ferric state, and with a variety of small heme-ligands bound, suggesting that hemophilin could function under a range of physiological conditions. Hemophilin knockout bacteria show a limited capacity to utilise free heme for growth. Our data suggest that hemophilin is a hemophore and that inhibition of NTHi occurs by heme starvation, raising the possibility that competition from hemophilin-producing H. haemolyticus could antagonise NTHi colonisation in the respiratory tract.
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Affiliation(s)
- Roger D Latham
- School of Medicine, University of Tasmania, Hobart, Australia
| | - Mario Torrado
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Brianna Atto
- School of Health Sciences, University of Tasmania, Launceston, Australia
| | - James L Walshe
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, Australia
| | - J Mitchell Guss
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Joel P Mackay
- School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Stephen Tristram
- School of Health Sciences, University of Tasmania, Launceston, Australia
| | - David A Gell
- School of Medicine, University of Tasmania, Hobart, Australia
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Rodríguez-Arce I, Al-Jubair T, Euba B, Fernández-Calvet A, Gil-Campillo C, Martí S, Törnroth-Horsefield S, Riesbeck K, Garmendia J. Moonlighting of Haemophilus influenzae heme acquisition systems contributes to the host airway-pathogen interplay in a coordinated manner. Virulence 2019; 10:315-333. [PMID: 30973092 PMCID: PMC6550540 DOI: 10.1080/21505594.2019.1596506] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/18/2019] [Accepted: 03/12/2019] [Indexed: 01/30/2023] Open
Abstract
Nutrient iron sequestration is the most significant form of nutritional immunity and causes bacterial pathogens to evolve strategies of host iron scavenging. Cigarette smoking contains iron particulates altering lung and systemic iron homeostasis, which may enhance colonization in the lungs of patients suffering chronic obstructive pulmonary disease (COPD) by opportunistic pathogens such as nontypeable. NTHi is a heme auxotroph, and the NTHi genome contains multiple heme acquisition systems whose role in pulmonary infection requires a global understanding. In this study, we determined the relative contribution to NTHi airway infection of the four heme-acquisition systems HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF that are located at the bacterial outer membrane or the periplasm. Our computational studies provided plausible 3D models for HbpA, SapA, PE, and HxuA interactions with heme. Generation and characterization of single mutants in the hxuCBA, hpe, sapA, and hbpA genes provided evidence for participation in heme binding-storage and inter-bacterial donation. The hxuA, sapA, hbpA, and hpe genes showed differential expression and responded to heme. Moreover, HxuCBA, PE, SapABCDFZ, and HbpA-DppBCDF presented moonlighting properties related to resistance to antimicrobial peptides or glutathione import, together likely contributing to the NTHi-host airway interplay, as observed upon cultured airway epithelia and in vivo lung infection. The observed multi-functionality was shown to be system-specific, thus limiting redundancy. Together, we provide evidence for heme uptake systems as bacterial factors that act in a coordinated and multi-functional manner to subvert nutritional- and other sources of host innate immunity during NTHi airway infection.
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Affiliation(s)
| | - Tamim Al-Jubair
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Begoña Euba
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | | | | | - Sara Martí
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
- Departamento Microbiología, Hospital Universitari Bellvitge, University of Barcelona, IDIBELL, Barcelona, Spain
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, Lund, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden
| | - Junkal Garmendia
- Instituto de Agrobiotecnología, CSIC-Gobierno, Navarra, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Harrison A, Hardison RL, Wallace RM, Fitch J, Heimlich DR, Bryan MO, Dubois L, John-Williams LS, Sebra RP, White P, Moseley MA, Thompson JW, Justice SS, Mason KM. Reprioritization of biofilm metabolism is associated with nutrient adaptation and long-term survival of Haemophilus influenzae. NPJ Biofilms Microbiomes 2019; 5:33. [PMID: 31700653 PMCID: PMC6831627 DOI: 10.1038/s41522-019-0105-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/03/2019] [Indexed: 01/14/2023] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) is a human-restricted pathogen with an essential requirement for heme-iron acquisition. We previously demonstrated that microevolution of NTHI promotes stationary phase survival in response to transient heme-iron restriction. In this study, we examine the metabolic contributions to biofilm formation using this evolved NTHI strain, RM33. Quantitative analyses identified 29 proteins, 55 transcripts, and 31 metabolites that significantly changed within in vitro biofilms formed by RM33. The synthesis of all enzymes within the tryptophan and glycogen pathways was significantly increased in biofilms formed by RM33 compared with the parental strain. In addition, increases were observed in metabolite transport, adhesin production, and DNA metabolism. Furthermore, we observed pyruvate as a pivotal point in the metabolic pathways associated with changes in cAMP phosphodiesterase activity during biofilm formation. Taken together, changes in central metabolism combined with increased stores of nutrients may serve to counterbalance nutrient sequestration.
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Affiliation(s)
- Alistair Harrison
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Rachael L. Hardison
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Rachel M. Wallace
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
| | - James Fitch
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, The Steve and Cindy Rasmussen Institute for Genomic Medicine, 575 Children’s Crossroad, Columbus, OH 43215 USA
| | - Derek R. Heimlich
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Meghan O’ Bryan
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Laura Dubois
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, 701 West Main Street, Durham, NC 27701 USA
| | - Lisa St. John-Williams
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, 701 West Main Street, Durham, NC 27701 USA
| | - Robert P. Sebra
- Icahn School of Medicine at Mount Sinai, Icahn Institute and Department of Genetics & Genomic Sciences, 1 Gustave L. Levy Place, New York, NY 10029 USA
| | - Peter White
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, The Steve and Cindy Rasmussen Institute for Genomic Medicine, 575 Children’s Crossroad, Columbus, OH 43215 USA
| | - M. Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, 701 West Main Street, Durham, NC 27701 USA
| | - J. Will Thompson
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, 701 West Main Street, Durham, NC 27701 USA
| | - Sheryl S. Justice
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
- Infectious Diseases Institute, The Ohio State University College of Medicine, 700 Children’s Drive, Columbus, OH 43205 USA
| | - Kevin M. Mason
- The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Center for Microbial Pathogenesis, 700 Children’s Drive, Columbus, OH 43205 USA
- Infectious Diseases Institute, The Ohio State University College of Medicine, 700 Children’s Drive, Columbus, OH 43205 USA
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12
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Discovery and Contribution of Nontypeable Haemophilus influenzae NTHI1441 to Human Respiratory Epithelial Cell Invasion. Infect Immun 2019; 87:IAI.00462-19. [PMID: 31427451 DOI: 10.1128/iai.00462-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/25/2019] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is the primary cause of bacterially induced acute exacerbations of chronic obstructive pulmonary disease (COPD). NTHi adheres to and invades host respiratory epithelial cells as a means to persist in the lower airways of adults with COPD. Therefore, we mined the genomes of NTHi strains isolated from the airways of adults with COPD to identify novel proteins to investigate their role in adherence and invasion of human respiratory epithelial cells. An isogenic knockout mutant of the open reading frame NTHI1441 showed a 76.6% ± 5.5% reduction in invasion of human bronchial and alveolar epithelial cells at 1, 3, and 6 h postinfection. Decreased invasion of the NTHI1441 mutant was independent of either intracellular survival or adherence to cells. NTHI1441 is conserved among NTHi genomes. Results of whole-bacterial-cell enzyme-linked immunosorbent assay (ELISA) and flow cytometry experiments identified that NTHI1441 has epitopes expressed on the bacterial cell surface. Adults with COPD develop increased serum IgG against NTHI1441 after experiencing an exacerbation with NTHi. This study reveals NTHI1441 as a novel NTHi virulence factor expressed during infection of the COPD lower airways that contributes to invasion of host respiratory epithelial cells. The role in host cell invasion, conservation among strains, and expression of surface-exposed epitopes suggest that NTHI1441 is a potential target for preventative and therapeutic interventions for disease caused by NTHi.
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13
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Tanaka KJ, Pinkett HW. Oligopeptide-binding protein from nontypeable Haemophilus influenzae has ligand-specific sites to accommodate peptides and heme in the binding pocket. J Biol Chem 2018; 294:1070-1082. [PMID: 30455346 DOI: 10.1074/jbc.ra118.004479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/14/2018] [Indexed: 11/06/2022] Open
Abstract
In nontypeable Haemophilus influenzae (NTHi), the oligopeptide-binding protein (OppA) serves as the substrate-binding protein (SBP) of the oligopeptide transport system responsible for the import of peptides. We solved the crystal structure of nthiOppA in complex with hydrophobic peptides of various sizes. Our novel hexapeptide complex demonstrates the flexibility of the nthiOppA-binding cavity to expand and accommodate the longer peptide while maintaining similar protein-peptide interactions of smaller peptide complexes. In addition to acquiring peptides from the host environment, as a heme auxotroph NTHi utilizes host hemoproteins as a source of essential iron. OppA is a member of the Cluster C SBP family, and unlike other SBP families, some members recognize two distinctly different substrates. DppA (dipeptide), MppA (murein tripeptide), and SapA (antimicrobial peptides) are Cluster C proteins known to also transport heme. We observed nthiOppA shares this heme-binding characteristic and established heme specificity and affinity by surface plasmon resonance (SPR) of the four Cluster C proteins in NTHi. Ligand-docking studies predicted a distinct heme-specific cleft in the binding pocket, and using SPR competition assays, we observed that heme does not directly compete with peptide in the substrate-binding pocket. Additionally, we identified that the individual nthiOppA domains differentially contribute to substrate binding, with one domain playing a dominant role in heme binding and the other in peptide binding. Our results demonstrate the multisubstrate specificity of nthiOppA and the role of NTHi Cluster C proteins in the heme-uptake pathway for this pathogen.
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Affiliation(s)
- Kari J Tanaka
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
| | - Heather W Pinkett
- From the Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208
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14
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Hardison RL, Heimlich DR, Harrison A, Beatty WL, Rains S, Moseley MA, Thompson JW, Justice SS, Mason KM. Transient Nutrient Deprivation Promotes Macropinocytosis-Dependent Intracellular Bacterial Community Development. mSphere 2018; 3:3/5/e00286-18. [PMID: 30209128 PMCID: PMC6135960 DOI: 10.1128/msphere.00286-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Nutrient limitation restricts bacterial growth in privileged sites such as the middle ear. Transient heme-iron restriction of nontypeable Haemophilus influenzae (NTHI), the major causative agent of chronic and recurrent otitis media (OM), promotes new and diverse phenotypes that can influence planktonic, biofilm, and intracellular lifestyles of NTHI. However, the bacterial responses to nutrient restriction that impact intracellular fate and survival of NTHI are unknown. In this work, we provide evidence for the role of transient heme-iron restriction in promoting the formation of intracellular bacterial communities (IBCs) of NTHI both in vitro and in vivo in a preclinical model of OM. We show that transient heme-iron restriction of NTHI results in significantly increased invasion and intracellular populations that escape or evade the endolysosomal pathway for increased intracellular survival. In contrast, NTHI continuously exposed to heme-iron traffics through the endolysosomal pathway for degradation. The use of pharmacological inhibitors revealed that prior heme-iron status does not appear to influence NTHI internalization through endocytic pathways. However, inhibition of macropinocytosis altered the intracellular fate of transiently restricted NTHI for degradation in the endolysosomal pathway. Furthermore, prevention of macropinocytosis significantly reduced the number of IBCs in cultured middle ear epithelial cells, providing evidence for the feasibility of this approach to reduce OM persistence. These results reveal that microenvironmental cues can influence the intracellular fate of NTHI, leading to new mechanisms for survival during disease progression.IMPORTANCE Otitis media is the most common bacterial infection in childhood. Current therapies are limited in the prevention of chronic or recurrent otitis media which leads to increased antibiotic exposure and represents a significant socioeconomic burden. In this study, we delineate the effect of nutritional limitation on the intracellular trafficking pathways used by nontypeable Haemophilus influenzae (NTHI). Moreover, transient limitation of heme-iron led to the development of intracellular bacterial communities that are known to contribute to persistence and recurrence in other diseases. New approaches for therapeutic interventions that reduce the production of intracellular bacterial communities and promote trafficking through the endolysosomal pathway were revealed through the use of pharmacological inhibition of macropinocytosis. This work demonstrates the importance of an intracellular niche for NTHI and provides new approaches for intervention for acute, chronic, and recurring episodes of otitis media.
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Affiliation(s)
- Rachael L Hardison
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Derek R Heimlich
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Alistair Harrison
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sarah Rains
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, USA
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, USA
| | - J Will Thompson
- Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, USA
| | - Sheryl S Justice
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Kevin M Mason
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
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15
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Cephalosporin-3'-Diazeniumdiolate NO Donor Prodrug PYRRO-C3D Enhances Azithromycin Susceptibility of Nontypeable Haemophilus influenzae Biofilms. Antimicrob Agents Chemother 2017; 61:AAC.02086-16. [PMID: 27919896 DOI: 10.1128/aac.02086-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/26/2016] [Indexed: 01/12/2023] Open
Abstract
PYRRO-C3D is a cephalosporin-3-diazeniumdiolate nitric oxide (NO) donor prodrug designed to selectively deliver NO to bacterial infection sites. The objective of this study was to assess the activity of PYRRO-C3D against nontypeable Haemophilus influenzae (NTHi) biofilms and examine the role of NO in reducing biofilm-associated antibiotic tolerance. The activity of PYRRO-C3D on in vitro NTHi biofilms was assessed through CFU enumeration and confocal microscopy. NO release measurements were performed using an ISO-NO probe. NTHi biofilms grown on primary ciliated respiratory epithelia at an air-liquid interface were used to investigate the effects of PYRRO-C3D in the presence of host tissue. Label-free liquid chromatography-mass spectrometry (LC/MS) proteomic analyses were performed to identify differentially expressed proteins following NO treatment. PYRRO-C3D specifically released NO in the presence of NTHi, while no evidence of spontaneous NO release was observed when the compound was exposed to primary epithelial cells. NTHi lacking β-lactamase activity failed to trigger NO release. Treatment significantly increased the susceptibility of in vitro NTHi biofilms to azithromycin, causing a log fold reduction (10-fold reduction or 1-log-unit reduction) in viability (P < 0.05) relative to azithromycin alone. The response was more pronounced for biofilms grown on primary respiratory epithelia, where a 2-log-unit reduction was observed (P < 0.01). Label-free proteomics showed that NO increased expression of 16 proteins involved in metabolic and transcriptional/translational functions. NO release from PYRRO-C3D enhances the efficacy of azithromycin against NTHi biofilms, putatively via modulation of NTHi metabolic activity. Adjunctive therapy with NO mediated through PYRRO-C3D represents a promising approach for reducing biofilm-associated antibiotic tolerance.
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16
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Choby JE, Skaar EP. Heme Synthesis and Acquisition in Bacterial Pathogens. J Mol Biol 2016; 428:3408-28. [PMID: 27019298 PMCID: PMC5125930 DOI: 10.1016/j.jmb.2016.03.018] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis.
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Affiliation(s)
- Jacob E Choby
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA; Tennessee Valley Healthcare System, U.S. Department of Veterans Affairs, Nashville, TN, USA.
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17
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Duell BL, Su YC, Riesbeck K. Host-pathogen interactions of nontypeable Haemophilus influenzae: from commensal to pathogen. FEBS Lett 2016; 590:3840-3853. [PMID: 27508518 DOI: 10.1002/1873-3468.12351] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/01/2016] [Accepted: 08/05/2016] [Indexed: 11/09/2022]
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a commensal microbe often isolated from the upper and lower respiratory tract. This bacterial species can cause sinusitis, acute otitis media in preschool children, exacerbations in patients suffering from chronic obstructive pulmonary disease, as well as conjunctivitis and bacteremia. Since the introduction of a vaccine against H. influenzae serotype b in the 1990s, the burden of H. influenzae-related infections has been increasingly dominated by NTHi. Understanding the ability of NTHi to cause infection is currently an expanding area of study. NTHi is able to exert differential binding to the host tissue through the use of a broad range of adhesins. NTHi survival in the host is multifaceted, that is, using virulence factors involved in complement resistance, biofilm, modified immunoglobulin responses, and, finally, formation and utilization of host proteins as a secondary strategy of increasing the adhesive ability.
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Affiliation(s)
- Benjamin Luke Duell
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Yu-Ching Su
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
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18
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Harrison A, Dubois LG, St John-Williams L, Moseley MA, Hardison RL, Heimlich DR, Stoddard A, Kerschner JE, Justice SS, Thompson JW, Mason KM. Comprehensive Proteomic and Metabolomic Signatures of Nontypeable Haemophilus influenzae-Induced Acute Otitis Media Reveal Bacterial Aerobic Respiration in an Immunosuppressed Environment. Mol Cell Proteomics 2015; 15:1117-38. [PMID: 26711468 DOI: 10.1074/mcp.m115.052498] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 12/31/2022] Open
Abstract
A thorough understanding of the molecular details of the interactions between bacteria and host are critical to ultimately prevent disease. Recent technological advances allow simultaneous analysis of host and bacterial protein and metabolic profiles from a single small tissue sample to provide insight into pathogenesis. We used the chinchilla model of human otitis media to determine, for the first time, the most expansive delineation of global changes in protein and metabolite profiles during an experimentally induced disease. After 48 h of infection with nontypeable Haemophilus influenzae, middle ear tissue lysates were analyzed by high-resolution quantitative two-dimensional liquid chromatography-tandem mass spectrometry. Dynamic changes in 105 chinchilla proteins and 66 metabolites define the early proteomic and metabolomic signature of otitis media. Our studies indicate that establishment of disease coincides with actin morphogenesis, suppression of inflammatory mediators, and bacterial aerobic respiration. We validated the observed increase in the actin-remodeling complex, Arp2/3, and experimentally showed a role for Arp2/3 in nontypeable Haemophilus influenzae invasion. Direct inhibition of actin branch morphology altered bacterial invasion into host epithelial cells, and is supportive of our efforts to use the information gathered to modify outcomes of disease. The twenty-eight nontypeable Haemophilus influenzae proteins identified participate in carbohydrate and amino acid metabolism, redox homeostasis, and include cell wall-associated metabolic proteins. Quantitative characterization of the molecular signatures of infection will redefine our understanding of host response driven developmental changes during pathogenesis. These data represent the first comprehensive study of host protein and metabolite profiles in vivo in response to infection and show the feasibility of extensive characterization of host protein profiles during disease. Identification of novel protein targets and metabolic biomarkers will advance development of therapeutic and diagnostic options for treatment of disease.
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Affiliation(s)
- Alistair Harrison
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Laura G Dubois
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Lisa St John-Williams
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - M Arthur Moseley
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Rachael L Hardison
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Derek R Heimlich
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | | | - Joseph E Kerschner
- ‖Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226; **Division of Pediatric Otolaryngology, Children's Hospital of Wisconsin, Milwaukee, Wisconsin 53226
| | - Sheryl S Justice
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; §The Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio 43210
| | - J Will Thompson
- ‡‡Duke Proteomics and Metabolomics Core Facility, Duke Center for Genomic and Computational Biology, Duke University, Medical Center, Durham, North Carolina 27710
| | - Kevin M Mason
- From the ‡The Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205; §The Center for Microbial Interface Biology and Department of Pediatrics, The Ohio State University, Columbus, Ohio 43210;
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19
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Shteinberg M, Rivlin J, Gur M, Konopnicki M, Stein N, Tunney MM, Elborn JS, Downey DG, Johnston E, Shalom H, Levy A. Lack of Association Between Haptoglobin Phenotype and Cystic Fibrosis Outcomes. Lung 2015; 193:1017-21. [PMID: 26370551 DOI: 10.1007/s00408-015-9801-z] [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: 04/15/2015] [Accepted: 09/07/2015] [Indexed: 11/25/2022]
Abstract
Haptoglobin (Hp), a heme-Iron chelator, has different isoforms which are associated with variable tendency toward infections: Hp 1-1, Hp 2-1, and Hp 2-2. Cystic fibrosis (CF) outcomes are variable and influenced by genetic and environmental factors. The aim of this study was to determine whether Hp phenotype influenced disease severity in CF. One hundred forty-two CF patients from two centers were analyzed for Haptoglobin phenotype using gel electrophoresis of hemoglobin enriched serum. Clinical and microbiological data including bacterial colonization status, lung function, presence of CF-related diabetes and liver disease, rate of exacerbation, and mortality were compared between Hp phenotype groups. We found a trend toward less mucoid PA among Hp 2-2 (20.4 %) compared with Hp 1-1 and Hp 2-1 individuals (33.3 %), p = 0.317. Hp 2-2 individuals also had less antibiotic courses, and lower inflammatory markers without statistical significance. Haptoglobin phenotype is unlikely to be an important modifier of CF phenotype.
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Affiliation(s)
- Michal Shteinberg
- CF Center, Carmel Medical Center, Haifa, Israel. .,Queens University Belfast, Belfast, UK. .,The B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel. .,Pulnonary Institute, Carmel Medical Center, 7 Michal St., 3463209, Haifa, Israel.
| | | | - Michal Gur
- CF Center, Carmel Medical Center, Haifa, Israel
| | | | - Nili Stein
- CF Center, Carmel Medical Center, Haifa, Israel
| | | | | | | | | | - Hadar Shalom
- The B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Andrew Levy
- The B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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20
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Tikhomirova A, Trappetti C, Paton JC, Kidd SP. The outcome of H. influenzae and S. pneumoniae inter-species interactions depends on pH, nutrient availability and growth phase. Int J Med Microbiol 2015; 305:881-92. [PMID: 26481153 DOI: 10.1016/j.ijmm.2015.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/07/2015] [Accepted: 09/10/2015] [Indexed: 01/16/2023] Open
Abstract
Haemophilus influenzae and Streptococcus pneumoniae exist together as common commensals of the healthy human nasopharynx, but both are important aetiological agents of different diseases, including the paediatric disease otitis media. It was recently shown that the formation of a multispecies biofilm of H. influenzae and S. pneumoniae is the cause of chronic forms of otitis media. However, the interactions between the two species are not clearly defined. Using a defined and kinetic analysis, our study has shown that while co-existence of the two species occurs, S. pneumoniae is also able to convert H. influenzae to a non-culturable state. We determined that this process was dependent on growth phase and pH. To analyse the H. influenzae/S. pneumoniae interactions in more depth, we investigated the growth and transcriptional profile in a pH-defined batch culture model, as well as in a growth phase independent flow cell system. Transcriptomics has shown that there are changes in gene expression in each of the species when grown in co-culture, intriguingly inducing the S. pneumoniae bacteriocin transport genes, and phage-associated genes in both species. Importantly, we have shown vast changes in gene expression in a group of S. pneumoniae metabolic genes, including those encoding lactose utilisation, glycerol utilisation and sugar transport proteins; we have shown that the expression of these genes depends not only on the presence of H. influenzae, but also on the growth system utilised.
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Affiliation(s)
- Alexandra Tikhomirova
- Research Centre for Infectious Disease, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Claudia Trappetti
- Research Centre for Infectious Disease, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Disease, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Stephen P Kidd
- Research Centre for Infectious Disease, School of Biological Sciences, The University of Adelaide, Adelaide, Australia.
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21
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Haemophilus influenzae: recent advances in the understanding of molecular pathogenesis and polymicrobial infections. Curr Opin Infect Dis 2015; 27:268-74. [PMID: 24699388 DOI: 10.1097/qco.0000000000000056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW Non-typeable Haemophilus influenzae (NTHi) is a human-specific mucosal pathogen and one of the most common causes of bacterial infections in children and patients with chronic obstructive pulmonary disease. It is also frequently found in polymicrobial superinfections. Great strides have recently been made in the understanding of the molecular mechanisms underlying NTHi pathogenesis. RECENT FINDINGS By using new methodology, such as experimental human colonization models and whole-genome approaches, investigators have shed light upon the various strategies of NTHi that are involved in pathogenesis. These include the escape of the mucociliary elevator, evasion of host immunity, survival in environments with scarce nutrients, and finally participation in polymicrobial infections. Lipooligosaccharide branching, proteinous adhesins, metabolic adaption to nutrient availability and many scavenging systems are implicated in these processes. Interestingly, genome-based studies comparing virulent and commensal strains have identified many hypothetical proteins as virulence determinants, suggesting that much regarding the molecular pathogenesis of NTHi remains to be solved. SUMMARY NTHi is an opportunistic pathogen and highly specialized colonizer of the human respiratory tract that has developed intricate mechanisms to establish growth and survival in the human host. Continued research is needed to further elucidate NTHi host-pathogen and pathogen-pathogen interactions.
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22
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Overlapping and complementary oxidative stress defense mechanisms in nontypeable Haemophilus influenzae. J Bacteriol 2014; 197:277-85. [PMID: 25368297 DOI: 10.1128/jb.01973-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative commensal bacterium nontypeable Haemophilus influenzae (NTHI) can cause respiratory tract diseases that include otitis media, sinusitis, exacerbations of chronic obstructive pulmonary disease, and bronchitis. During colonization and infection, NTHI withstands oxidative stress generated by reactive oxygen species produced endogenously, by the host, and by other copathogens and flora. These reactive oxygen species include superoxide, hydrogen peroxide (H2O2), and hydroxyl radicals, whose killing is amplified by iron via the Fenton reaction. We previously identified genes that encode proteins with putative roles in protection of the NTHI isolate strain 86-028NP against oxidative stress. These include catalase (HktE), peroxiredoxin/glutaredoxin (PgdX), and a ferritin-like protein (Dps). Strains were generated with mutations in hktE, pgdX, and dps. The hktE mutant and a pgdX hktE double mutant were more sensitive than the parent to killing by H2O2. Conversely, the pgdX mutant was more resistant to H2O2 due to increased catalase activity. Supporting the role of killing via the Fenton reaction, binding of iron by Dps significantly mitigated the effect of H2O2-mediated killing. NTHI thus utilizes several effectors to resist oxidative stress, and regulation of free iron is critical to this protection. These mechanisms will be important for successful colonization and infection by this opportunistic human pathogen.
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23
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Justice SS, Harrison A, Becknell B, Mason KM. Bacterial differentiation, development, and disease: mechanisms for survival. FEMS Microbiol Lett 2014; 360:1-8. [PMID: 25228010 DOI: 10.1111/1574-6968.12602] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/04/2014] [Accepted: 09/11/2014] [Indexed: 12/27/2022] Open
Abstract
Bacteria have the exquisite ability to maintain a precise diameter, cell length, and shape. The dimensions of bacteria size and shape are a classical metric in the distinction of bacterial species. Much of what we know about the particular morphology of any given species is the result of investigations of planktonic cultures. As we explore deeper into the natural habitats of bacteria, it is increasingly clear that bacteria can alter their morphology in response to the environment in which they reside. Specific morphologies are also becoming recognized as advantageous for survival in hostile environments. This is of particular importance in the context of both colonization and infection in the host. There are multiple examples of bacterial pathogens that use morphological changes as a mechanism for evasion of host immune responses and continued persistence. This review will focus on two systems where specific morphological changes are essential for persistence in animal models of human disease. We will also offer insight into the mechanism underlying the morphological changes and how these morphotypes aid in persistence. Additional examples of morphological changes associated with survival will be presented.
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Affiliation(s)
- Sheryl S Justice
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; The Ohio State University School of Medicine, Columbus, OH, USA
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24
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Su YC, Resman F, Hörhold F, Riesbeck K. Comparative genomic analysis reveals distinct genotypic features of the emerging pathogen Haemophilus influenzae type f. BMC Genomics 2014; 15:38. [PMID: 24438474 PMCID: PMC3928620 DOI: 10.1186/1471-2164-15-38] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The incidence of invasive disease caused by encapsulated Haemophilus influenzae type f (Hif) has increased in the post-H. influenzae type b (Hib) vaccine era. We previously annotated the first complete Hif genome from a clinical isolate (KR494) that caused septic shock and necrotizing myositis. Here, the full genome of Hif KR494 was compared to sequenced reference strains Hib 10810, capsule type d (Hid) Rd Kw20, and finally nontypeable H. influenzae 3655. The goal was to identify possible genomic characteristics that may shed light upon the pathogenesis of Hif. RESULTS The Hif KR494 genome exhibited large regions of synteny with other H. influenzae, but also distinct genome rearrangements. A predicted Hif core genome of 1390 genes was shared with the reference strains, and 6 unique genomic regions comprising half of the 191 unique coding sequences were revealed. The majority of these regions were inserted genetic fragments, most likely derived from the closely-related Haemophilus spp. including H. aegyptius, H. haemolyticus and H. parainfluenzae. Importantly, the KR494 genome possessed several putative virulence genes that were distinct from non-type f strains. These included the sap2 operon, aef3 fimbriae, and genes for kanamycin nucleotidyltranserase, iron-utilization proteins, and putative YadA-like trimeric autotransporters that may increase the bacterial virulence. Furthermore, Hif KR494 lacked a hisABCDEFGH operon for de novo histidine biosynthesis, hmg locus for lipooligosaccharide biosynthesis and biofilm formation, the Haemophilus antibiotic resistance island and a Haemophilus secondary molybdate transport system. We confirmed the histidine auxotrophy and kanamycin resistance in Hif by functional experiments. Moreover, the pattern of unique or missing genes of Hif KR494 was similar in 20 Hif clinical isolates obtained from different years and geographical areas. A cross-species comparison revealed that the Hif genome shared more characteristics with H. aegyptius than Hid and NTHi. CONCLUSIONS The genomic comparative analyses facilitated identification of genotypic characteristics that may be related to the specific virulence of Hif. In relation to non-type f H. influenzae strains, the Hif genome contains differences in components involved in metabolism and survival that may contribute to its invasiveness.
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Affiliation(s)
| | | | | | - Kristian Riesbeck
- Medical Microbiology, Department of Laboratory Medicine Malmö, Lund University, Jan Waldenströms gata 59, SE-205 02 Malmö, Sweden.
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Haemophilus responses to nutritional immunity: epigenetic and morphological contribution to biofilm architecture, invasion, persistence and disease severity. PLoS Pathog 2013; 9:e1003709. [PMID: 24130500 PMCID: PMC3795038 DOI: 10.1371/journal.ppat.1003709] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 08/30/2013] [Indexed: 12/18/2022] Open
Abstract
In an effort to suppress microbial outgrowth, the host sequesters essential nutrients in a process termed nutritional immunity. However, inflammatory responses to bacterial insult can restore nutritional resources. Given that nutrient availability modulates virulence factor production and biofilm formation by other bacterial species, we hypothesized that fluctuations in heme-iron availability, particularly at privileged sites, would similarly influence Haemophilus biofilm formation and pathogenesis. Thus, we cultured Haemophilus through sequential heme-iron deplete and heme-iron replete media to determine the effect of transient depletion of internal stores of heme-iron on multiple pathogenic phenotypes. We observed that prior heme-iron restriction potentiates biofilm changes for at least 72 hours that include increased peak height and architectural complexity as compared to biofilms initiated from heme-iron replete bacteria, suggesting a mechanism for epigenetic responses that participate in the changes observed. Additionally, in a co-infection model for human otitis media, heme-iron restricted Haemophilus, although accounting for only 10% of the inoculum (90% heme-iron replete), represented up to 99% of the organisms recovered at 4 days. These data indicate that fluctuations in heme-iron availability promote a survival advantage during disease. Filamentation mediated by a SulA-related ortholog was required for optimal biofilm peak height and persistence during experimental otitis media. Moreover, severity of disease in response to heme-iron restricted Haemophilus was reduced as evidenced by lack of mucosal destruction, decreased erythema, hemorrhagic foci and vasodilatation. Transient restriction of heme-iron also promoted productive invasion events leading to the development of intracellular bacterial communities. Taken together, these data suggest that nutritional immunity, may, in fact, foster long-term phenotypic changes that better equip bacteria for survival at infectious sites. Clinical management of upper and lower respiratory tract diseases caused by nontypeable Haemophilus influenzae (NTHI) is a significant socioeconomic burden. Therapies targeting the pathogenic lifestyle of NTHI remain non-existent due to a lack of understanding of host microenvironmental cues and bacterial responses that dictate NTHI persistence. Iron availability influences bacterial virulence traits and biofilm formation; yet, host sequestration of iron serves to restrict bacterial growth. We predicted that fluctuations in availability of iron-containing compounds, typically associated with infection, would impact NTHI pathogenesis. We demonstrated that transient restriction of heme-iron triggered an epigenetic developmental program that enhanced NTHI biofilm architecture, directly influenced by induced morphological changes in bacterial length. Heme-iron restricted bacteria were primed for survival in the mammalian middle ear, due in part to an observed reduction in host inflammation coinciding with a striking reduction in host mucosal epithelial damage, compared to that observed in response to heme-iron replete NTHI. Moreover, transiently restricted NTHI were more invasive of epithelial cells resulting in formation of intracellular bacterial communities. Our findings significantly advance our understanding of how host immune pressure and nutrient availability influence pathogenic behaviors that impact disease severity.
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Frirdich E, Gaynor EC. Peptidoglycan hydrolases, bacterial shape, and pathogenesis. Curr Opin Microbiol 2013; 16:767-78. [PMID: 24121030 DOI: 10.1016/j.mib.2013.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/08/2013] [Accepted: 09/11/2013] [Indexed: 01/29/2023]
Abstract
Bacterial shape has always been hypothesized to play an important role in the biology of a species and in the ability of certain bacteria to influence human health. The recent discovery of peptidoglycan hydrolases that modulate shape has now allowed this hypothesis to be addressed directly. Genetic, biochemical, and phenotypic studies have found that changes in shape and underlying peptidoglycan structure influence many pathogenic attributes including surviving unfavorable conditions, predation, transmission, colonization, and host interactions. The diversity of bacterial shapes, niches, and lifestyles is also reflected in diverse mechanisms of hydrolase regulation, critical for maintaining peptidoglycan integrity and biological properties of the cell. Future studies will build on the current work described and further elucidate the intersection of peptidoglycan hydrolase activity, shape, and disease outcome.
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Affiliation(s)
- Emilisa Frirdich
- Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T1Z3
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The Haemophilus influenzae Sap transporter mediates bacterium-epithelial cell homeostasis. Infect Immun 2012; 81:43-54. [PMID: 23071138 DOI: 10.1128/iai.00942-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) is a commensal inhabitant of the human nasopharynx and a causative agent of otitis media and other diseases of the upper and lower human airway. During colonization within the host, NTHI must acquire essential nutrients and evade immune attack. We previously demonstrated that the NTHI Sap transporter, an inner membrane protein complex, mediates resistance to antimicrobial peptides and is required for heme homeostasis. We hypothesized that Sap transporter functions are critical for NTHI interaction with the host epithelium and establishment of colonization. Thus, we cocultured the parent or the sapA mutant on polarized epithelial cells grown at an air-liquid interface, as a physiological model of NTHI colonization, to determine the contribution of the Sap transporter to bacterium-host cell interactions. Although SapA-deficient NTHI was less adherent to epithelial cells, we observed a significant increase in invasive bacteria compared to the parent strain. Upon internalization, the sapA mutant appeared free in the cytoplasm, whereas the parent strain was primarily found in endosomes, indicating differential subcellular trafficking. Additionally, we observed reduced inflammatory cytokine production by the epithelium in response to the sapA mutant strain compared to the parental strain. Furthermore, chinchilla middle ears challenged with the sapA mutant demonstrated a decrease in disease severity compared to ears challenged with the parental strain. Collectively, our data suggest that NTHI senses host environmental cues via Sap transporter function to mediate interaction with host epithelial cells. Epithelial cell invasion and modulation of host inflammatory cytokine responses may promote NTHI colonization and access to essential nutrients.
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