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Zahid A, Wilson JC, Grice ID, Peak IR. Otitis media: recent advances in otitis media vaccine development and model systems. Front Microbiol 2024; 15:1345027. [PMID: 38328427 PMCID: PMC10847372 DOI: 10.3389/fmicb.2024.1345027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/08/2024] [Indexed: 02/09/2024] Open
Abstract
Otitis media is an inflammatory disorder of the middle ear caused by airways-associated bacterial or viral infections. It is one of the most common childhood infections as globally more than 80% of children are diagnosed with acute otitis media by 3 years of age and it is a common reason for doctor's visits, antibiotics prescriptions, and surgery among children. Otitis media is a multifactorial disease with various genetic, immunologic, infectious, and environmental factors predisposing children to develop ear infections. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are the most common culprits responsible for acute otitis media. Despite the massive global disease burden, the pathogenesis of otitis media is still unclear and requires extensive future research. Antibiotics are the preferred treatment to cure middle ear infections, however, the antimicrobial resistance rate of common middle ear pathogens has increased considerably over the years. At present, pneumococcal and influenza vaccines are administered as a preventive measure against otitis media, nevertheless, these vaccines are only beneficial in preventing carriage and/or disease caused by vaccine serotypes. Otitis media caused by non-vaccine serotype pneumococci, non-typeable H. influenza, and M. catarrhalis remain an important healthcare burden. The development of multi-species vaccines is an arduous process but is required to reduce the global burden of this disease. Many novel vaccines against S. pneumoniae, non-typeable H. influenza, and M. catarrhalis are in preclinical trials. It is anticipated that these vaccines will lower the disease burden and provide better protection against otitis media. To study disease pathology the rat, mouse, and chinchilla are commonly used to induce experimental acute otitis media to test new therapeutics, including antibiotics and vaccines. Each of these models has its advantages and disadvantages, yet there is still a need to develop an improved animal model providing a better correlated mechanistic understanding of human middle ear infections, thereby underpinning the development of more effective otitis media therapeutics. This review provides an updated summary of current vaccines against otitis media, various animal models of otitis media, their limitations, and some future insights in this field providing a springboard in the development of new animal models and novel vaccines for otitis media.
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Affiliation(s)
- Ayesha Zahid
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Jennifer C. Wilson
- School of Pharmacy and Medical Science, Griffith University, Gold Coast, QLD, Australia
| | - I. Darren Grice
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
- School of Pharmacy and Medical Science, Griffith University, Gold Coast, QLD, Australia
| | - Ian R. Peak
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
- School of Pharmacy and Medical Science, Griffith University, Gold Coast, QLD, Australia
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Muralidharan C, Quinteros JA, Anwar A, Wilson TB, Scott PC, Moore RJ, Van TTH. The use of filamentous hemagglutinin adhesin to detect immune responses to Campylobacter hepaticus infections in layer hens. Front Vet Sci 2022; 9:1082358. [PMID: 36619951 PMCID: PMC9811313 DOI: 10.3389/fvets.2022.1082358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Campylobacter hepaticus is the aetiological agent of Spotty Liver Disease (SLD). SLD can cause significant production loss and mortalities among layer hens at and around peak of lay. We previously developed an enzyme linked immunosorbent assay (ELISA), SLD-ELISA1, to detect C. hepaticus specific antibodies from bird sera using C. hepaticus total proteins and sera pre-absorbed with Campylobacter jejuni proteins. The high specificity achieved with SLD-ELISA1 indicated the presence of C. hepaticus specific antibodies in sera of infected birds. However, some of the reagents used in SLD-ELISA1 are time consuming to prepare and difficult to quality control. This understanding led to the search for C. hepaticus specific immunogenic proteins that could be used in recombinant forms as antibody capture antigens in immunoassay design. In this study, an immunoproteomic approach that combined bioinformatics analysis, western blotting, and LC MS/MS protein profiling was used, and a fragment of filamentous hemagglutinin adhesin (FHA), FHA1,628-1,899 with C. hepaticus specific antigenicity was identified. Recombinant FHA1,628-1,899 was used as antigen coating on ELISA plates to capture FHA1,628-1,899 specific antibodies in sera of infected birds. SLD-ELISA2, based on the purified recombinant FHA fragment, is more user-friendly and standardizable than SLD-ELISA1 for screening antibody responses to C. hepaticus exposure in hens. This study is the first report of the use of FHA from a Campylobacter species in immunoassays, and it also opens future research directions to investigate the role of FHA in C. hepaticus pathogenesis and its effectiveness as a vaccine candidate.
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Affiliation(s)
| | | | - Arif Anwar
- Scolexia Pty Ltd., Moonee Ponds, VIC, Australia
| | | | | | - Robert J. Moore
- School of Science, Royal Melbourne Institute of Technology University, Bundoora, VIC, Australia
| | - Thi Thu Hao Van
- School of Science, Royal Melbourne Institute of Technology University, Bundoora, VIC, Australia,*Correspondence: Thi Thu Hao Van ✉
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Paudel G, Amatya N, Saud B, Wagle S, Shrestha V, Adhikari B. Nasal colonization by potential bacterial pathogens in healthy kindergarten children of Nepal: a prevalence study. Germs 2022; 12:86-98. [PMID: 35601953 PMCID: PMC9113680 DOI: 10.18683/germs.2022.1309] [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: 10/04/2021] [Revised: 01/10/2022] [Accepted: 01/18/2022] [Indexed: 09/29/2023]
Abstract
INTRODUCTION In low- and middle-income countries including Nepal, respiratory tract infection (RTI) is considered as one of the most prominent public health problems in children. Multiple carriage of respiratory pathogens is common in children, especially in preschoolers as they are easily transmitted through close contact and poor hygienic condition. Thus, this research is based on the study of prevalence, co-existence, associated factors and antibiogram of nasal isolates among healthy preschoolers. METHODS The study was conducted in four randomly selected kindergarten schools (two government run and two private run) of Bhaktapur Municipality. Out of a total 140 students, 136 eligible participants of age group 2-5 years old were involved in the study. Nasal swab was collected for the isolation of five target isolates (Staphylococcus aureus, Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae and Haemophilus parainfluenzae) and their antibiotic resistance determination. RESULTS Of 136 participants involved, 128 (94.5%) were positive for carriage of at least one of the target bacteria. The most common isolate was M. catarrhalis 62.5% (80/128) followed by S. aureus 43.0% (55/128). There was a significant difference in bacterial carriage with respect to type of school (p value<0.05, OR=0.50, CI=0.20-0.90). Regarding bacterial co-existence, the most common co-existence was of S. aureus and M. catarrhalis & S. pneumoniae and M. catarrhalis 48.8%. Multiple logistic regression analysis showed that S. aureus was negatively associated with S. pneumoniae, M. catarrhalis and H. influenzae and S. pneumoniae was positively associated with M. catarrhalis and H. influenzae. Multidrug resistance was seen in 63 isolates (29.4%). CONCLUSIONS Nepalese kindergarten children are at a high risk of respiratory tract infection by multidrug resistant bacteria.
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Affiliation(s)
- Govinda Paudel
- MSc, Assistant Prof, Department of Medical Laboratory Technology, Janamaitri Foundation Institute of Health Sciences (JFIHS), GPO Box 8322, Kathmandu, Nepal
| | - Neetu Amatya
- BSc, Clinical Laboratory Instructor, Department of Medical Laboratory Technology, Janamaitri Foundation Institute of Health Sciences (JFIHS), GPO Box 8322, Kathmandu, Nepal
| | - Bhuvan Saud
- MSc, Associate Professor, Department of Medical Laboratory Technology, Janamaitri Foundation Institute of Health Sciences (JFIHS), GPO Box 8322, Kathmandu, Nepal
| | - Sunita Wagle
- MSc, Laboratory Technician, Dhading Hospital Dhading, Government of Nepal. GPO box 4512, Dhading, Nepal
| | - Vikram Shrestha
- MSc, Assistant Professor, Department of Medical Laboratory Technology, Janamaitri Foundation Institute of Health Sciences (JFIHS), GPO Box 8322, Kathmandu, Nepal
| | - Bibhav Adhikari
- MM, Lecturer, College of Management, Little Angels’ College of Higher Studies, GPO Box 8322, Hattiban, Lalitpur, Nepal
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Alderson MR, Murphy T, Pelton SI, Novotny LA, Hammitt LL, Kurabi A, Li JD, Thornton RB, Kirkham LAS. Panel 8: Vaccines and immunology. Int J Pediatr Otorhinolaryngol 2020; 130 Suppl 1:109839. [PMID: 31948716 PMCID: PMC7153269 DOI: 10.1016/j.ijporl.2019.109839] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To review and highlight significant advances made towards vaccine development and understanding of the immunology of otitis media (OM) since the 19th International Symposium on Recent Advances in Otitis Media (ISOM) in 2015, as well as identify future research directions and knowledge gaps. DATA SOURCES PubMed database, National Library of Medicine. REVIEW METHODS Key topics were assigned to each panel member for detailed review. Draft reviews were collated, circulated, and thoroughly discussed when the panel met at the 20th ISOM in June 2019. The final manuscript was prepared with input from all panel members. CONCLUSIONS Since 2015 there have been a number of studies assessing the impact of licensed pneumococcal vaccines on OM. While these studies have confirmed that these vaccines are effective in preventing carriage and/or disease caused by vaccine serotypes, OM caused by non-vaccine serotype pneumococci and other otopathogens remains a significant health care burden globally. Development of multi-species vaccines is challenging but essential to reducing the global burden of OM. Influenza vaccination has been shown to prevent acute OM, and with novel vaccines against nontypeable Haemophilus influenzae (NTHi), Moraxella catarrhalis and Respiratory Syncytial Virus (RSV) in clinical trials, the potential to significantly prevent OM is within reach. Research into alternative vaccine delivery strategies has demonstrated the power of maternal and mucosal vaccination for OM prevention. Future OM vaccine trials must include molecular diagnostics of middle ear effusion, for detection of viruses and bacteria that are persisting in biofilms and to enable accurate assessment of vaccine impact on OM etiology. Understanding population differences in natural and vaccine-induced immune responses to otopathogens is also important for development of the most effective OM vaccines. Improved understanding of the interaction between otopathogens will also advance development of effective therapies and encourage the assessment of the indirect benefits of vaccination. IMPLICATIONS FOR PRACTICE While NTHi and M. catarrhalis are the predominant otopathogens, funding opportunities to drive vaccine development for these species are limited due to a focus on prevention of childhood mortality rather than morbidity. Delivery of a comprehensive report on the high financial and social costs of OM, including the potential for OM vaccines to reduce antibiotic use and subsequent development of antimicrobial resistance (AMR), would likely assist in engaging stakeholders to recognize the value of prevention of OM and increase support for efforts on OM vaccine development. Vaccine trials with OM prevention as a clinical end-point are challenging, however a focus on developing assays that measure functional correlates of protection would facilitate OM vaccine development.
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Affiliation(s)
| | - Tim Murphy
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Stephen I Pelton
- Boston University School of Public Health, Boston University, Boston, MA, USA
| | - Laura A Novotny
- The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Laura L Hammitt
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Arwa Kurabi
- Division of Otolaryngology, Department of Surgery, University of California, San Diego, CA, USA
| | - Jian-Dong Li
- Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, GA, USA
| | - Ruth B Thornton
- School of Biomedical Sciences, University of Western Australia, Australia and Wesfarmers Centre for Vaccines and Infectious Diseases Research, Telethon Kids Institute, Perth, Australia
| | - Lea-Ann S Kirkham
- Wesfarmers Centre for Vaccines and Infectious Diseases Research, Telethon Kids Institute, Australia and Centre for Child Health Research, University of Western Australia, Perth, Australia
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Martonos CO, Damian A, Alexandru G, Viorel M, Rus V, Stan FG. Morphological and morphometrical aspects of intima and media of the common, external and internal iliac arteries in Chinchilla lanigera (Rodentia, Chinchillidae) bred in captivity. THE EUROPEAN ZOOLOGICAL JOURNAL 2020. [DOI: 10.1080/24750263.2020.1815876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- C. O. Martonos
- Department of Anatomy, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - A. Damian
- Department of Anatomy, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - G. Alexandru
- Department of Anatomy, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - M. Viorel
- Department of Histology, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - V. Rus
- Department of Histology, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
| | - F. G. Stan
- Department of Anatomy, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Cluj-Napoca, Romania
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Perez AC, Murphy TF. A Moraxella catarrhalis vaccine to protect against otitis media and exacerbations of COPD: An update on current progress and challenges. Hum Vaccin Immunother 2017; 13:2322-2331. [PMID: 28853985 PMCID: PMC5647992 DOI: 10.1080/21645515.2017.1356951] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/16/2017] [Accepted: 07/12/2017] [Indexed: 01/03/2023] Open
Abstract
Moraxella catarrhalis is a major cause of morbidity and mortality worldwide, especially causing otitis media in young children and exacerbations of chronic obstructive pulmonary disease in adults. This pathogen uses several virulence mechanisms to colonize and survive in its host, including adherence and invasion of host cells, formation of polymicrobial biofilms with other bacterial pathogens, and production of β-lactamase. Given the global impact of otitis media and COPD, an effective vaccine to prevent M. catarrhalis infection would have a huge impact on the quality of life in both patient populations by preventing disease, thus reducing morbidity and health care costs. A number of promising vaccine antigens have been identified for M. catarrhalis. The development of improved animal models of M. catarrhalis disease and identification of a correlate of protection are needed to accelerate vaccine development. This review will discuss the current state of M. catarrhalis vaccine development, and the challenges that must be addressed to succeed.
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Affiliation(s)
- Antonia C. Perez
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA
- Division of Infectious Diseases, Department of Medicine, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Timothy F. Murphy
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA
- Division of Infectious Diseases, Department of Medicine, University at Buffalo, The State University of New York, Buffalo, NY, USA
- Department of Microbiology, University at Buffalo, The State University of New York, Buffalo, NY, USA
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Antibodies against In Vivo-Expressed Antigens Are Sufficient To Protect against Lethal Aerosol Infection with Burkholderia mallei and Burkholderia pseudomallei. Infect Immun 2017; 85:IAI.00102-17. [PMID: 28507073 DOI: 10.1128/iai.00102-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Burkholderia mallei, a facultative intracellular bacterium and tier 1 biothreat, causes the fatal zoonotic disease glanders. The organism possesses multiple genes encoding autotransporter proteins, which represent important virulence factors and targets for developing countermeasures in pathogenic Gram-negative bacteria. In the present study, we investigated one of these autotransporters, BatA, and demonstrate that it displays lipolytic activity, aids in intracellular survival, is expressed in vivo, elicits production of antibodies during infection, and contributes to pathogenicity in a mouse aerosol challenge model. A mutation in the batA gene of wild-type strain ATCC 23344 was found to be particularly attenuating, as BALB/c mice infected with the equivalent of 80 median lethal doses cleared the organism. This finding prompted us to test the hypothesis that vaccination with the batA mutant strain elicits protective immunity against subsequent infection with wild-type bacteria. We discovered that not only does vaccination provide high levels of protection against lethal aerosol challenge with B. mallei ATCC 23344, it also protects against infection with multiple isolates of the closely related organism and causative agent of melioidosis, Burkholderia pseudomallei Passive-transfer experiments also revealed that the protective immunity afforded by vaccination with the batA mutant strain is predominantly mediated by IgG antibodies binding to antigens expressed exclusively in vivo Collectively, our data demonstrate that BatA is a target for developing medical countermeasures and that vaccination with a mutant lacking expression of the protein provides a platform to gain insights regarding mechanisms of protective immunity against B. mallei and B. pseudomallei, including antigen discovery.
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Pettigrew MM, Alderson MR, Bakaletz LO, Barenkamp SJ, Hakansson AP, Mason KM, Nokso-Koivisto J, Patel J, Pelton SI, Murphy TF. Panel 6: Vaccines. Otolaryngol Head Neck Surg 2017; 156:S76-S87. [PMID: 28372533 DOI: 10.1177/0194599816632178] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Objective To review the literature on progress regarding (1) effectiveness of vaccines for prevention of otitis media (OM) and (2) development of vaccine antigens for OM bacterial and viral pathogens. Data Sources PubMed database of the National Library of Science. Review Methods We performed literature searches in PubMed for OM pathogens and candidate vaccine antigens, and we restricted the searches to articles in English that were published between July 2011 and June 2015. Panel members reviewed literature in their area of expertise. Conclusions Pneumococcal conjugate vaccines (PCVs) are somewhat effective for the prevention of pneumococcal OM, recurrent OM, OM visits, and tympanostomy tube insertions. Widespread use of PCVs has been associated with shifts in pneumococcal serotypes and bacterial pathogens associated with OM, diminishing PCV effectiveness against AOM. The 10-valent pneumococcal vaccine containing Haemophilus influenzae protein D (PHiD-CV) is effective for pneumococcal OM, but results from studies describing the potential impact on OM due to H influenzae have been inconsistent. Progress in vaccine development for H influenzae, Moraxella catarrhalis, and OM-associated respiratory viruses has been limited. Additional research is needed to extend vaccine protection to additional pneumococcal serotypes and other otopathogens. There are likely to be licensure challenges for protein-based vaccines, and data on correlates of protection for OM vaccine antigens are urgently needed. Implications for Practice OM continues to be a significant health care burden globally. Prevention is preferable to treatment, and vaccine development remains an important goal. As a polymicrobial disease, OM poses significant but not insurmountable challenges for vaccine development.
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Affiliation(s)
- Melinda M Pettigrew
- 1 Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven Connecticut, USA
| | | | - Lauren O Bakaletz
- 3 Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | | | | | - Kevin M Mason
- 3 Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, and Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | | | - Janak Patel
- 7 University of Texas Medical Branch, Galveston, Texas, USA
| | - Stephen I Pelton
- 8 Boston University School of Medicine, Boston, Massachusetts, USA
| | - Timothy F Murphy
- 9 University at Buffalo, The State University of New York, Buffalo, New York, USA
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Perez AC, Murphy TF. Potential impact of a Moraxella catarrhalis vaccine in COPD. Vaccine 2017; 37:5551-5558. [PMID: 28185742 DOI: 10.1016/j.vaccine.2016.12.066] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/28/2016] [Indexed: 12/27/2022]
Abstract
Moraxella catarrhalis is the second most common cause of exacerbations in adults with COPD, resulting in enormous morbidity and mortality in this clinical setting. Vaccine development for M. catarrhalis has lagged behind the other two important causes of exacerbations in COPD, nontypeable Haemophilus influenzae and Streptococcus pneumoniae. While no licensed vaccine is currently available for M. catarrhalis, several promising candidate vaccine antigens have been identified and characterized and are close to entering clinical trials. Key steps that are required to advance vaccines for M. catarrhalis along the translational pipeline include standardization of assay systems to assess candidate antigens, identification of a reliable correlate of protection and expansion of partnerships between industry, academia and government to overcome regulatory hurdles. A vaccine to prevent M. catarrhalis infections in COPD would have a major impact in reducing morbidity, mortality and healthcare costs in COPD.
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Affiliation(s)
- Antonia C Perez
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA; Division of Infectious Diseases, Department of Medicine, University at Buffalo, The State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA
| | - Timothy F Murphy
- Clinical and Translational Research Center, University at Buffalo, The State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA; Division of Infectious Diseases, Department of Medicine, University at Buffalo, The State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA; Department of Microbiology, University at Buffalo, The State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA.
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Karner A, Gesslbauer B, Spreitzer A, Almer J, Smidt M, Schüler W, Fartmann B, Zimmermann W, Meinke A, Kungl AJ. Profiling the Membrane and Glycosaminoglycan-Binding Proteomes of Moraxella catarrhalis. J Proteome Res 2016; 15:3055-97. [DOI: 10.1021/acs.jproteome.6b00187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Anita Karner
- Institute
of Pharmaceutical Sciences, University of Graz, Universitaetsplatz
1, A-8010 Graz, Austria
| | - Bernd Gesslbauer
- Institute
of Pharmaceutical Sciences, University of Graz, Universitaetsplatz
1, A-8010 Graz, Austria
| | - Anton Spreitzer
- Institute
of Pharmaceutical Sciences, University of Graz, Universitaetsplatz
1, A-8010 Graz, Austria
| | - Johannes Almer
- Institute
of Pharmaceutical Sciences, University of Graz, Universitaetsplatz
1, A-8010 Graz, Austria
| | | | | | | | | | | | - Andreas J. Kungl
- Institute
of Pharmaceutical Sciences, University of Graz, Universitaetsplatz
1, A-8010 Graz, Austria
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Zimmerman SM, Michel F, Hogan RJ, Lafontaine ER. The Autotransporter BpaB Contributes to the Virulence of Burkholderia mallei in an Aerosol Model of Infection. PLoS One 2015; 10:e0126437. [PMID: 25993100 PMCID: PMC4438868 DOI: 10.1371/journal.pone.0126437] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/02/2015] [Indexed: 02/06/2023] Open
Abstract
Burkholderia mallei is a highly pathogenic bacterium that causes the zoonosis glanders. Previous studies indicated that the genome of the organism contains eight genes specifying autotransporter proteins, which are important virulence factors of Gram-negative bacteria. In the present study, we report the characterization of one of these autotransporters, BpaB. Database searches identified the bpaB gene in ten B. mallei isolates and the predicted proteins were 99-100% identical. Comparative sequence analyses indicate that the gene product is a trimeric autotransporter of 1,090 amino acids with a predicted molecular weight of 105-kDa. Consistent with this finding, we discovered that recombinant bacteria expressing bpaB produce a protein of ≥300-kDa on their surface that is reactive with a BpaB-specific monoclonal antibody. Analysis of sera from mice infected with B. mallei indicated that animals produce antibodies against BpaB during the course of disease, thus establishing production of the autotransporter in vivo. To gain insight on its role in virulence, we inactivated the bpaB gene of B. mallei strain ATCC 23344 and determined the median lethal dose of the mutant in a mouse model of aerosol infection. These experiments revealed that the bpaB mutation attenuates virulence 8-14 fold. Using a crystal violet-based assay, we also discovered that constitutive production of BpaB on the surface of B. mallei promotes biofilm formation. To our knowledge, this is the first report of a biofilm factor for this organism.
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Affiliation(s)
- Shawn M. Zimmerman
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
| | - Frank Michel
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Robert J. Hogan
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- Department of Veterinary Biosciences and Diagnostic Imaging, University of Georgia College of Veterinary Medicine, Athens, GA, United States of America
| | - Eric R. Lafontaine
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, United States of America
- * E-mail:
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Lafontaine ER, Balder R, Michel F, Hogan RJ. Characterization of an autotransporter adhesin protein shared by Burkholderia mallei and Burkholderia pseudomallei. BMC Microbiol 2014; 14:92. [PMID: 24731253 PMCID: PMC4021183 DOI: 10.1186/1471-2180-14-92] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 04/08/2014] [Indexed: 12/21/2022] Open
Abstract
Background Autotransporters form a large family of outer membrane proteins specifying diverse biological traits of Gram-negative bacteria. In this study, we report the identification and characterization of a novel autotransporter gene product of Burkholderia mallei (locus tag BMA1027 in strain ATCC 23344). Results Database searches identified the gene in at least seven B. mallei isolates and the encoded proteins were found to be 84% identical. Inactivation of the gene encoding the autotransporter in the genome of strain ATCC 23344 substantially reduces adherence to monolayers of HEp-2 laryngeal cells and A549 type II pneumocytes, as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, expression of the autotransporter on the surface of recombinant E. coli bacteria increases adherence to these cell types by 5–7 fold. The gene specifying the autotransporter was identified in the genome of 29 B. pseudomallei isolates and disruption of the gene in strain DD503 reduced adherence to NHBE cultures by 61%. Unlike B. mallei, the mutation did not impair binding of B. pseudomallei to A549 or HEp-2 cells. Analysis of sera from mice infected via the aerosol route with B. mallei and B. pseudomallei revealed that animals inoculated with as few as 10 organisms produce antibodies against the autotransporter, therefore indicating expression in vivo. Conclusions Our data demonstrate that we have identified an autotransporter protein common to the pathogenic species B. mallei and B. pseudomallei which mediates adherence to respiratory epithelial cells and is expressed in vivo during the course of aerosol infection.
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Affiliation(s)
- Eric R Lafontaine
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, 30602 Athens, GA, USA.
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