1
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Liu YL, Ding R, Jia XM, Huang JJ, Yu S, Chan HT, Li W, Mao LL, Zhang L, Zhang XY, Wu W, Ni AP, Xu YC. Correlation of Moraxella catarrhalis macrolide susceptibility with the ability to adhere and invade human respiratory epithelial cells. Emerg Microbes Infect 2022; 11:2055-2068. [PMID: 35904140 PMCID: PMC9448378 DOI: 10.1080/22221751.2022.2108341] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recently, the prevalence of macrolide-resistant Moraxella catarrhalis has been reported, especially among Chinese children. The fitness cost of resistance is reported to render the resistant bacteria less virulent. To investigate the correlation between macrolide susceptibility of M. catarrhalis and pathogenicity, the whole genome of 70 M. catarrhalis isolates belonging to four clonal complexes with different macrolide susceptibilities was sequenced. The gene products were annotated with the Gene Ontology terms. Based on 46 extracted essential virulence genes, 19 representative isolates were selected to infect type II alveolar cells (A549 cells). The ability of these isolates to adhere and invade human epithelial cells and to produce cytokines was comparatively analysed. Furthermore, mice were infected with a pair of M. catarrhalis isolates with different pathogenic behaviours and macrolide susceptibilities to examine pulmonary clearance, histological findings, and the production of cytokines. The percentages of annotations for binding, metabolic process, cellular process, and cell were non-significantly different between the macrolide-resistant and macrolide-susceptible groups. The presence of uspA2, uspA2H, pilO, lbpB, lex1, modM, mboIA, and mboIB significantly differed among the four clonal complexes and macrolide susceptibility groups. Furthermore, compared with those in macrolide-susceptible isolates, the adhesion ability was stronger (P = 0.0019) and the invasion ability was weaker (P < 0.0001) in the macrolide-resistant isolates. Mouse experiments revealed that pulmonary macrophages elicit immune responses against M. catarrhalis infection by significantly upregulating the Csf2, Il4, Il13, Il1b, Il6, Tnf, and Il18. Therefore, M. catarrhalis populations exhibited diverse pathogenicity in vitro and in vivo.
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Affiliation(s)
- Ya-Li Liu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107).,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing 100730, China
| | - Rui Ding
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Xin-Miao Jia
- Medical Research Center, State Key laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, China
| | - Jing-Jing Huang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107).,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing 100730, China
| | - Shuying Yu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107).,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing 100730, China
| | - Hiu Tat Chan
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Wei Li
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Lei-Li Mao
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Li Zhang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Xin-Yao Zhang
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Wei Wu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - An-Ping Ni
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107)
| | - Ying-Chun Xu
- Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100730, China (Li Zhang, Employee ID: 10107).,Graduate School, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing 100730, China
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2
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Hijacking host components for bacterial biofilm formation: An advanced mechanism. Int Immunopharmacol 2021; 103:108471. [PMID: 34952466 DOI: 10.1016/j.intimp.2021.108471] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022]
Abstract
Biofilm is a community of bacteria embedded in the extracellular matrix that accounts for 80% of bacterial infections. Biofilm enables bacterial cells to provide particular conditions and produce virulence determinants in response to the unavailability of micronutrients and local oxygen, resulting in their resistance to various antibacterial agents. Besides, the human immune reactions are not completely competent in the elimination of biofilm. Most importantly, the growing body of evidence shows that some bacterial spp. use a variety of mechanisms by which hijack the host components to form biofilm. In this regard, host components, such as DNA, hyaluronan, collagen, fibronectin, mucin, oligosaccharide moieties, filamentous polymers (F-actin), plasma, platelets, keratin, sialic acid, laminin, vitronectin, C3- and C4- binding proteins, antibody, proteases, factor I, factor H, and acidic proline-rich proteins have been reviewed. Hence, the characterization of interactions between bacterial biofilm and the host would be critical to effectively address biofilm-associated infections. In this paper, we review the latest information on the hijacking of host factors by bacteria to form biofilm.
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3
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Ysebaert C, Castado C, Mortier MC, Rioux S, Feron C, Di Paolo E, Weynants V, Blais N, Devos N, Hermand P. UspA2 is a cross-protective Moraxella catarrhalis vaccine antigen. Vaccine 2021; 39:5641-5649. [PMID: 34446318 DOI: 10.1016/j.vaccine.2021.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022]
Abstract
Moraxella catarrhalis (Mcat) is a key pathogen associated with exacerbations of chronic obstructive pulmonary disease (COPD) in adults and playing a significant role in otitis media in children. A vaccine would help to reduce the morbidity and mortality associated with these diseases. UspA2 is an Mcat surface antigen considered earlier as vaccine candidate before the interest in this molecule vanished due to sequence variability. However, the observation that some conserved domains are the target of bactericidal antibodies prompted us to reconsider UspA2 as a potential vaccine antigen. We first determined its prevalence among the COPD patients from the AERIS study, as the prevalence of UspA2 in a COPD-restricted population had yet to be documented. The gene was found in all Mcat isolates either as UspA2 or UspA2H variant. The percentage of UspA2H variant was higher than in any report so far, reaching 51%. A potential link between the role of UspA2H in biofilm formation and this high prevalence is discussed. To study further UspA2 as a vaccine antigen, recombinant UspA2 molecules were designed and used in animal models and bactericidal assays. We showed that UspA2 is immunogenic and that UspA2 immunization clears Mcat pulmonary challenge in a mouse model. In a serum bactericidal assay, anti-UspA2 antibodies generated in mice, guinea pigs or rabbits were able to kill Mcat strains of various origins, including a subset of isolates from the AERIS study, cross-reacting with UspA2H and even UspA1, a closely related Mcat surface protein. In conclusion, UspA2 is a cross-reactive Mcat antigen presenting the characteristics of a vaccine candidate.
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4
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Yu M, Zhao Y. Cell permeability, β-lactamase activity, and transport contribute to high level of resistance to ampicillin in Lysobacter enzymogenes. Appl Microbiol Biotechnol 2019; 104:1149-1161. [PMID: 31822985 DOI: 10.1007/s00253-019-10266-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/12/2019] [Accepted: 11/22/2019] [Indexed: 11/26/2022]
Abstract
Discovery of multidrug resistance (MDR) in environmental microorganisms provides unique resources for uncovering antibiotic resistomes, which could be vital to predict future emergence of MDR pathogens. Our previous studies indicated that Lysobacter sp. conferred intrinsic resistance to multiple antibiotics at high levels, especially ampicillin, the first broad-spectrum β-lactam antibiotics against both Gram-positive and Gram-negative bacteria. However, the underlying molecular mechanisms for resistance to ampicillin in Lysobacter enzymogenes strain C3 (LeC3) remain unknown. In this study, screening a Tn5 transposon mutant library of LeC3 recovered 12 mutants with decreased ampicillin resistance, and three mutants (i.e., tatC, lebla, and lpp) were selected for further characterization. Our results revealed that genes encoding β-lactamase (lebla) and twin-arginine translocation (tatC) system for β-lactamase transport played a pivotal role in conferring ampicillin resistance in L. enzymogenes. It was also demonstrated that the lpp gene was not only involved in resistance against β-lactams but also conferred resistance to multiple antibiotics in L. enzymogenes. Permeability assay results indicated that decreased MDR in the lpp mutant was in part due to its higher cellular permeability. Furthermore, our results showed that the difference of LeC3 and L. antibioticus strain LaATCC29479 in ampicillin susceptibility was partly due to their differences in cellular permeability, but not due to β-lactamase activities.
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Affiliation(s)
- Menghao Yu
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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5
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Silva MD, Sillankorva S. Otitis media pathogens – A life entrapped in biofilm communities. Crit Rev Microbiol 2019; 45:595-612. [DOI: 10.1080/1040841x.2019.1660616] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Maria Daniela Silva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
| | - Sanna Sillankorva
- CEB – Centre of Biological Engineering, LIBRO – Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Braga, Portugal
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6
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Utilization of Variant and Fusion Proteins To Functionally Map the Aggregatibacter actinomycetemcomitans Trimeric Autotransporter Protein ApiA. Infect Immun 2018; 86:IAI.00697-17. [PMID: 29229732 DOI: 10.1128/iai.00697-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/01/2017] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative bacterium Aggregatibacter actinomycetemcomitans is a causative agent of localized aggressive periodontitis. Critical to its infection process is the first and essential step of attachment, which is related to the coordinated functions of surface components comprised of proteins and extracellular polysaccharides. One such protein is the outer membrane trimeric autotransporter protein ApiA, a versatile virulence factor with numerous functions, including cell binding, invasion, serum resistance, autoaggregation, and induction of cytokine release. Here we report on the use of Escherichia coli strains expressing protein variants to define the separate functions ascribed to the N terminus and those related to the C terminus. Importantly, a hybrid protein that comprised the N terminus of trimeric ApiA and the β-barrel domain of monomeric autotransporter Aae was constructed, which allowed the expression of a monomer surface-exposed domain of ApiA. Functional and phenotypic analyses demonstrated that the C terminus of ApiA forms an independent domain that is crucial for general stability and trimer formation, which appears to be associated with autoaggregation, biofilm formation, and surface expression. Importantly, the results show that the monomeric form of the N-terminal passenger domain of ApiA, while surface exposed, is sufficient for binding to buccal epithelial cells; however, it is not sufficient to allow aggregation and biofilm formation, strengthening the importance of the role of trimerization in these phenotypes.
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7
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Blakeway LV, Tan A, Peak IRA, Seib KL. Virulence determinants of Moraxella catarrhalis: distribution and considerations for vaccine development. MICROBIOLOGY-SGM 2017; 163:1371-1384. [PMID: 28893369 DOI: 10.1099/mic.0.000523] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Moraxella catarrhalis is a human-restricted opportunistic bacterial pathogen of the respiratory mucosa. It frequently colonizes the nasopharynx asymptomatically, but is also an important causative agent of otitis media (OM) in children, and plays a significant role in acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults. As the current treatment options for M. catarrhalis infection in OM and exacerbations of COPD are often ineffective, the development of an efficacious vaccine is warranted. However, no vaccine candidates for M. catarrhalis have progressed to clinical trials, and information regarding the distribution of M. catarrhalis virulence factors and vaccine candidates is inconsistent in the literature. It is largely unknown if virulence is associated with particular strains or subpopulations of M. catarrhalis, or if differences in clinical manifestation can be attributed to the heterogeneous expression of specific M. catarrhalis virulence factors in the circulating population. Further investigation of the distribution of M. catarrhalis virulence factors in the context of carriage and disease is required so that vaccine development may be targeted at relevant antigens that are conserved among disease-causing strains. The challenge of determining which of the proposed M. catarrhalis virulence factors are relevant to human disease is amplified by the lack of a standardized M. catarrhalis typing system to facilitate direct comparisons of worldwide isolates. Here we summarize and evaluate proposed relationships between M. catarrhalis subpopulations and specific virulence factors in the context of colonization and disease, as well as the current methods used to infer these associations.
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Affiliation(s)
- Luke V Blakeway
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Aimee Tan
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Ian R A Peak
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.,School of Medical Science, Griffith University, Gold Coast, Queensland, Australia
| | - Kate L Seib
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
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8
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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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9
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A Moraxella catarrhalis two-component signal transduction system necessary for growth in liquid media affects production of two lysozyme inhibitors. Infect Immun 2014; 83:146-60. [PMID: 25312959 DOI: 10.1128/iai.02486-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
There are a paucity of data concerning gene products that could contribute to the ability of Moraxella catarrhalis to colonize the human nasopharynx. Inactivation of a gene (mesR) encoding a predicted response regulator of a two-component signal transduction system in M. catarrhalis yielded a mutant unable to grow in liquid media. This mesR mutant also exhibited increased sensitivity to certain stressors, including polymyxin B, SDS, and hydrogen peroxide. Inactivation of the gene (mesS) encoding the predicted cognate sensor (histidine) kinase yielded a mutant with the same inability to grow in liquid media as the mesR mutant. DNA microarray and real-time reverse transcriptase PCR analyses indicated that several genes previously shown to be involved in the ability of M. catarrhalis to persist in the chinchilla nasopharynx were upregulated in the mesR mutant. Two other open reading frames upregulated in the mesR mutant were shown to encode small proteins (LipA and LipB) that had amino acid sequence homology to bacterial adhesins and structural homology to bacterial lysozyme inhibitors. Inactivation of both lipA and lipB did not affect the ability of M. catarrhalis O35E to attach to a human bronchial epithelial cell line in vitro. Purified recombinant LipA and LipB fusion proteins were each shown to inhibit human lysozyme activity in vitro and in saliva. A lipA lipB deletion mutant was more sensitive than the wild-type parent strain to killing by human lysozyme in the presence of human apolactoferrin. This is the first report of the production of lysozyme inhibitors by M. catarrhalis.
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10
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Luke-Marshall NR, Mang TS, Hansen LA, Campagnari AA. Moraxella catarrhalisis susceptible to antimicrobial photodynamic therapy with Photofrin. Lasers Surg Med 2014; 46:712-7. [DOI: 10.1002/lsm.22287] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Nicole R. Luke-Marshall
- Department of Microbiology and Immunology; State University of New York at Buffalo; Buffalo New York
| | - Thomas S. Mang
- Department of Oral and Maxillofacial Surgery; State University of New York at Buffalo; Buffalo New York
| | - Lisa A. Hansen
- Department of Microbiology and Immunology; State University of New York at Buffalo; Buffalo New York
| | - Anthony A. Campagnari
- Department of Microbiology and Immunology; State University of New York at Buffalo; Buffalo New York
- Department of Medicine; State University of New York at Buffalo; Buffalo New York
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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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12
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Identification of an outer membrane lipoprotein involved in nasopharyngeal colonization by Moraxella catarrhalis in an animal model. Infect Immun 2014; 82:2287-99. [PMID: 24643539 DOI: 10.1128/iai.01745-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Colonization of the human nasopharynx by Moraxella catarrhalis is presumed to involve attachment of this bacterium to the mucosa. DNA microarray analysis was used to determine whether attachment of M. catarrhalis to human bronchial epithelial (HBE) cells in vitro affected gene expression in this bacterium. Attachment affected expression of at least 454 different genes, with 163 being upregulated and 291 being downregulated. Among the upregulated genes was one (ORF113) previously annotated as encoding a protein with some similarity to outer membrane protein A (OmpA). The protein encoded by ORF113 was predicted to have a signal peptidase II cleavage site, and globomycin inhibition experiments confirmed that this protein was indeed a lipoprotein. The ORF113 protein also contained a predicted peptidoglycan-binding domain in its C-terminal half. The use of mutant and recombinant M. catarrhalis strains confirmed that the ORF113 protein was present in outer membrane preparations, and this protein was also shown to be at least partially exposed on the bacterial cell surface. A mutant unable to produce the ORF113 protein showed little or no change in its growth rate in vitro, in its ability to attach to HBE cells in vitro, or in its autoagglutination characteristics, but it did exhibit a reduced ability to survive in the chinchilla nasopharynx. This is the first report of a lipoprotein essential to the ability of M. catarrhalis to persist in an animal model.
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13
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Moraxella catarrhalis uses a twin-arginine translocation system to secrete the β-lactamase BRO-2. BMC Microbiol 2013; 13:140. [PMID: 23782650 PMCID: PMC3695778 DOI: 10.1186/1471-2180-13-140] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/10/2013] [Indexed: 12/13/2022] Open
Abstract
Background Moraxella catarrhalis is a human-specific gram-negative bacterium readily isolated from the respiratory tract of healthy individuals. The organism also causes significant health problems, including 15-20% of otitis media cases in children and ~10% of respiratory infections in adults with chronic obstructive pulmonary disease. The lack of an efficacious vaccine, the rapid emergence of antibiotic resistance in clinical isolates, and high carriage rates reported in children are cause for concern. Virtually all Moraxella catarrhalis isolates are resistant to β-lactam antibiotics, which are generally the first antibiotics prescribed to treat otitis media in children. The enzymes responsible for this resistance, BRO-1 and BRO-2, are lipoproteins and the mechanism by which they are secreted to the periplasm of M. catarrhalis cells has not been described. Results Comparative genomic analyses identified M. catarrhalis gene products resembling the TatA, TatB, and TatC proteins of the well-characterized Twin Arginine Translocation (TAT) secretory apparatus. Mutations in the M. catarrhalis tatA, tatB and tatC genes revealed that the proteins are necessary for optimal growth and resistance to β-lactams. Site-directed mutagenesis was used to replace highly-conserved twin arginine residues in the predicted signal sequence of M. catarrhalis strain O35E BRO-2, which abolished resistance to the β-lactam antibiotic carbanecillin. Conclusions Moraxella catarrhalis possesses a TAT secretory apparatus, which plays a key role in growth of the organism and is necessary for secretion of BRO-2 into the periplasm where the enzyme can protect the peptidoglycan cell wall from the antimicrobial activity of β-lactam antibiotics.
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Murphy TF, Chonmaitree T, Barenkamp S, Kyd J, Nokso-Koivisto J, Patel JA, Heikkinen T, Yamanaka N, Ogra P, Swords WE, Sih T, Pettigrew MM. Panel 5: Microbiology and immunology panel. Otolaryngol Head Neck Surg 2013; 148:E64-89. [PMID: 23536533 DOI: 10.1177/0194599812459636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The objective is to perform a comprehensive review of the literature from January 2007 through June 2011 on the virology, bacteriology, and immunology related to otitis media. DATA SOURCES PubMed database of the National Library of Medicine. REVIEW METHODS Three subpanels with co-chairs comprising experts in the virology, bacteriology, and immunology of otitis media were formed. Each of the panels reviewed the literature in their respective fields and wrote draft reviews. The reviews were shared with all panel members, and a second draft was created. The entire panel met at the 10th International Symposium on Recent Advances in Otitis Media in June 2011 and discussed the review and refined the content further. A final draft was created, circulated, and approved by the panel. CONCLUSION Excellent progress has been made in the past 4 years in advancing an understanding of the microbiology and immunology of otitis media. Advances include laboratory-based basic studies, cell-based assays, work in animal models, and clinical studies. IMPLICATIONS FOR PRACTICE The advances of the past 4 years formed the basis of a series of short-term and long-term research goals in an effort to guide the field. Accomplishing these goals will provide opportunities for the development of novel interventions, including new ways to better treat and prevent otitis media.
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Affiliation(s)
- Timothy F Murphy
- Clinical and Translational Research Center, University at Buffalo, State University of New York, Buffalo, New York 14203, USA.
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Su YC, Hallström BM, Bernhard S, Singh B, Riesbeck K. Impact of sequence diversity in the Moraxella catarrhalis UspA2/UspA2H head domain on vitronectin binding and antigenic variation. Microbes Infect 2013; 15:375-87. [DOI: 10.1016/j.micinf.2013.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/15/2013] [Accepted: 02/11/2013] [Indexed: 12/31/2022]
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16
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de Vries SPW, Burghout P, Langereis JD, Zomer A, Hermans PWM, Bootsma HJ. Genetic requirements for Moraxella catarrhalis growth under iron-limiting conditions. Mol Microbiol 2012; 87:14-29. [PMID: 23163337 DOI: 10.1111/mmi.12081] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2012] [Indexed: 11/26/2022]
Abstract
Iron sequestration by the human host is a first line defence against respiratory pathogens like Moraxella catarrhalis, which consequently experiences a period of iron starvation during colonization. We determined the genetic requirements for M. catarrhalis BBH18 growth during iron starvation using the high-throughput genome-wide screening technology genomic array footprinting (GAF). By subjecting a large random transposon mutant library to growth under iron-limiting conditions, mutants of the MCR_0996-rhlB-yggW operon, rnd, and MCR_0457 were negatively selected. Growth experiments using directed mutants confirmed the GAF phenotypes with ΔyggW (putative haem-shuttling protein) and ΔMCR_0457 (hypothetical protein) most severely attenuated during iron starvation, phenotypes which were restored upon genetic complementation of the deleted genes. Deletion of yggW resulted in similar attenuated phenotypes in three additional strains. Transcriptional profiles of ΔyggW and ΔMCR_0457 were highly altered with 393 and 192 differentially expressed genes respectively. In all five mutants, expression of nitrate reductase genes was increased and of nitrite reductase decreased, suggesting an impaired aerobic respiration. Alteration of iron metabolism may affect nasopharyngeal colonization as adherence of all mutants to respiratory tract epithelial cells was attenuated. In conclusion, we elucidated the genetic requirements for M. catarrhalis growth during iron starvation and characterized the roles of the identified genes in bacterial growth and host interaction.
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Affiliation(s)
- Stefan P W de Vries
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Centre, Nijmegen, the Netherlands
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17
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Percival SL, Hill KE, Williams DW, Hooper SJ, Thomas DW, Costerton JW. A review of the scientific evidence for biofilms in wounds. Wound Repair Regen 2012; 20:647-57. [DOI: 10.1111/j.1524-475x.2012.00836.x] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - Katja E. Hill
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | | | - Samuel J. Hooper
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | - Dave W. Thomas
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | - John W. Costerton
- Center for Genomic Sciences; Allegheny-Singer Research Institute; Pittsburgh; Pennsylvania
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18
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Hu Q, Zhu Y, Tu J, Yin Y, Wang X, Han X, Ding C, Zhang B, Yu S. Identification of the genes involved in Riemerella anatipestifer biofilm formation by random transposon mutagenesis. PLoS One 2012; 7:e39805. [PMID: 22768127 PMCID: PMC3387259 DOI: 10.1371/journal.pone.0039805] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 05/27/2012] [Indexed: 01/13/2023] Open
Abstract
Riemerella anatipestifer causes epizootics of infectious disease in poultry that result in serious economic losses to the duck industry. Our previous studies have shown that some strains of R. anatipestifer can form a biofilm, and this may explain the intriguing persistence of R. anatipestifer on duck farms post infection. In this study we used strain CH3, a strong producer of biofilm, to construct a library of random Tn4351 transposon mutants in order to investigate the genetic basis of biofilm formation by R. anatipestifer on abiotic surfaces. A total of 2,520 mutants were obtained and 39 of them showed a reduction in biofilm formation of 47%–98% using crystal violet staining. Genetic characterization of the mutants led to the identification of 33 genes. Of these, 29 genes are associated with information storage and processing, as well as basic cellular processes and metabolism; the function of the other four genes is currently unknown. In addition, a mutant strain BF19, in which biofilm formation was reduced by 98% following insertion of the Tn4351 transposon at the dihydrodipicolinate synthase (dhdps) gene, was complemented with a shuttle plasmid pCP-dhdps. The complemented mutant strain was restored to give 92.6% of the biofilm formation of the wild-type strain CH3, which indicates that the dhdp gene is associated with biofilm formation. It is inferred that such complementation applies also to other mutant strains. Furthermore, some biological characteristics of biofilm-defective mutants were investigated, indicating that the genes deleted in the mutant strains function in the biofilm formation of R. anatipestifer. Deletion of either gene will stall the biofilm formation at a specific stage thus preventing further biofilm development. In addition, the tested biofilm-defective mutants had different adherence capacity to Vero cells. This study will help us to understand the molecular mechanisms of biofilm development by R. anatipestifer and to study the pathogenesis of R. anatipestifer further.
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Affiliation(s)
- Qinghai Hu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Yinyu Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Jing Tu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Yuncong Yin
- College of Veterinary Medicine, Nanjing Agricultural University,Nanjing, People’s Republic of China
| | - Xiaolan Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Xiangan Han
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Beimin Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
- China National Engineering Technology Research Centre for Poultry, Shanghai, People’s Republic of China
- * E-mail:
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Blanchette KA, Orihuela CJ. Future perspective on host-pathogen interactions during bacterial biofilm formation within the nasopharynx. Future Microbiol 2012; 7:227-39. [PMID: 22324992 DOI: 10.2217/fmb.11.160] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Nasopharyngeal colonization provides bacteria with a place of residence, a platform for person-to-person transmission and for many opportunistic pathogens it is a prerequisite event towards the development of invasive disease. Therefore, how host factors within the nasopharynx contribute to, inhibit or otherwise shape biofilm formation, the primary mode of existence for colonizing bacteria, and how biofilm bacteria subvert the acute inflammatory response that facilitates clearance, are important topics for future microbiological research. This review proposes the examination of host components as bridging molecules for bacterial interactions during biofilm formation, altered virulence determinant production and cell wall modification as a mechanism for immunoquiescence, and the role of host factors as signals and co-opted mechanisms for bacterial dissemination, together providing an opportunity for disease.
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Affiliation(s)
- Krystle A Blanchette
- The University of Texas Health Science Center at San Antonio, Department of Microbiology & Immunology, 7703 Floyd Curl Drive, MC7758, San Antonio, TX 78229-3900, USA
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Moraxella catarrhalis – Pathogen or Commensal? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 697:107-16. [DOI: 10.1007/978-1-4419-7185-2_9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Identification of gene products involved in the oxidative stress response of Moraxella catarrhalis. Infect Immun 2010; 79:745-55. [PMID: 21098105 DOI: 10.1128/iai.01060-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Moraxella catarrhalis is subjected to oxidative stress from both internal and environmental sources. A previous study (C. D. Pericone, K. Overweg, P. W. Hermans, and J. N. Weiser, Infect. Immun. 68:3990-3997, 2000) indicated that a wild-type strain of M. catarrhalis was very resistant to killing by exogenous hydrogen peroxide (H₂O₂). The gene encoding OxyR, a LysR family transcriptional regulator, was identified and inactivated in M. catarrhalis strain O35E, resulting in an increase in sensitivity to killing by H₂O₂ in disk diffusion assays and a concomitant aerobic serial dilution effect. Genes encoding a predicted catalase (KatA) and an alkyl hydroperoxidase (AhpCF) showed dose-dependent upregulation in wild-type cells exposed to H₂O₂. DNA microarray and real-time reverse transcription-PCR (RT-PCR) analyses identified M. catarrhalis genes whose expression was affected by oxidative stress in an OxyR-dependent manner. Testing of M. catarrhalis O35E katA and ahpC mutants for their abilities to scavenge exogenous H₂O₂ showed that the KatA catalase was responsible for most of this activity in the wild-type parent strain. The introduction of the same mutations into M. catarrhalis strain ETSU-4 showed that the growth of a ETSU-4 katA mutant was markedly inhibited by the addition of 50 mM H₂O₂ but that this mutant could still form a biofilm equivalent to that produced by its wild-type parent strain.
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Identification of Burkholderia mallei and Burkholderia pseudomallei adhesins for human respiratory epithelial cells. BMC Microbiol 2010; 10:250. [PMID: 20920184 PMCID: PMC2955633 DOI: 10.1186/1471-2180-10-250] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Accepted: 09/28/2010] [Indexed: 11/10/2022] Open
Abstract
Background Burkholderia pseudomallei and Burkholderia mallei cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which B. pseudomallei and B. mallei adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms. Results Comparative sequence analyses identified a gene product in the published genome of B. mallei strain ATCC23344 (locus # BMAA0649) that resembles the well-characterized Yersinia enterocolitica autotransporter adhesin YadA. The gene encoding this B. mallei protein, designated boaA, was expressed in Escherichia coli and shown to significantly increase adherence to human epithelial cell lines, specifically HEp2 (laryngeal cells) and A549 (type II pneumocytes), as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, disruption of the boaA gene in B. mallei ATCC23344 reduced adherence to all three cell types by ~50%. The genomes of the B. pseudomallei strains K96243 and DD503 were also found to contain boaA and inactivation of the gene in DD503 considerably decreased binding to monolayers of HEp2 and A549 cells and to NHBE cultures. A second YadA-like gene product highly similar to BoaA (65% identity) was identified in the published genomic sequence of B. pseudomallei strain K96243 (locus # BPSL1705). The gene specifying this protein, termed boaB, appears to be B. pseudomallei-specific. Quantitative attachment assays demonstrated that recombinant E. coli expressing BoaB displayed greater binding to A549 pneumocytes, HEp2 cells and NHBE cultures. Moreover, a boaB mutant of B. pseudomallei DD503 showed decreased adherence to these respiratory cells. Additionally, a B. pseudomallei strain lacking expression of both boaA and boaB was impaired in its ability to thrive inside J774A.1 murine macrophages, suggesting a possible role for these proteins in survival within professional phagocytic cells. Conclusions The boaA and boaB genes specify adhesins that mediate adherence to epithelial cells of the human respiratory tract. The boaA gene product is shared by B. pseudomallei and B. mallei whereas BoaB appears to be a B. pseudomallei-specific adherence factor.
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Molecular aspects of Moraxella catarrhalis pathogenesis. Microbiol Mol Biol Rev 2009; 73:389-406, Table of Contents. [PMID: 19721084 DOI: 10.1128/mmbr.00007-09] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In recent years, Moraxella catarrhalis has established its position as an important human mucosal pathogen, no longer being regarded as just a commensal bacterium. Further, current research in the field has led to a better understanding of the molecular mechanisms involved in M. catarrhalis pathogenesis, including mechanisms associated with cellular adherence, target cell invasion, modulation of the host's immune response, and metabolism. Additionally, in order to be successful in the host, M. catarrhalis has to be able to interact and compete with the commensal flora and overcome stressful environmental conditions, such as nutrient limitation. In this review, we provide a timely overview of the current understanding of the molecular mechanisms associated with M. catarrhalis virulence and pathogenesis.
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Attia AS, Sedillo JL, Hoopman TC, Liu W, Liu L, Brautigam CA, Hansen EJ. Identification of a bacteriocin and its cognate immunity factor expressed by Moraxella catarrhalis. BMC Microbiol 2009; 9:207. [PMID: 19781080 PMCID: PMC2761928 DOI: 10.1186/1471-2180-9-207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 09/25/2009] [Indexed: 12/23/2022] Open
Abstract
Background Bacteriocins are antimicrobial proteins and peptides ribosomally synthesized by some bacteria which can effect both intraspecies and interspecies killing. Results Moraxella catarrhalis strain E22 containing plasmid pLQ510 was shown to inhibit the growth of M. catarrhalis strain O35E. Two genes (mcbA and mcbB) in pLQ510 encoded proteins predicted to be involved in the secretion of a bacteriocin. Immediately downstream from these two genes, a very short ORF (mcbC) encoded a protein which had some homology to double-glycine bacteriocins produced by other bacteria. A second very short ORF (mcbI) immediately downstream from mcbC encoded a protein which had no significant similarity to other proteins in the databases. Cloning and expression of the mcbI gene in M. catarrhalis O35E indicated that this gene encoded the cognate immunity factor. Reverse transcriptase-PCR was used to show that the mcbA, mcbB, mcbC, and mcbI ORFs were transcriptionally linked. This four-gene cluster was subsequently shown to be present in the chromosome of several M. catarrhalis strains including O12E. Inactivation of the mcbA, mcbB, or mcbC ORFs in M. catarrhalis O12E eliminated the ability of this strain to inhibit the growth of M. catarrhalis O35E. In co-culture experiments involving a M. catarrhalis strain containing the mcbABCI locus and one which lacked this locus, the former strain became the predominant member of the culture after overnight growth in broth. Conclusion This is the first description of a bacteriocin and its cognate immunity factor produced by M. catarrhalis. The killing activity of the McbC protein raises the possibility that it might serve to lyse other M. catarrhalis strains that lack the mcbABCI locus, thereby making their DNA available for lateral gene transfer.
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Affiliation(s)
- Ahmed S Attia
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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25
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Hag mediates adherence of Moraxella catarrhalis to ciliated human airway cells. Infect Immun 2009; 77:4597-608. [PMID: 19667048 DOI: 10.1128/iai.00212-09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Moraxella catarrhalis is a human pathogen causing otitis media in infants and respiratory infections in adults, particularly patients with chronic obstructive pulmonary disease. The surface protein Hag (also designated MID) has previously been shown to be a key adherence factor for several epithelial cell lines relevant to pathogenesis by M. catarrhalis, including NCIH292 lung cells, middle ear cells, and A549 type II pneumocytes. In this study, we demonstrate that Hag mediates adherence to air-liquid interface cultures of normal human bronchial epithelium (NHBE) exhibiting mucociliary activity. Immunofluorescent staining and laser scanning confocal microscopy experiments demonstrated that the M. catarrhalis wild-type isolates O35E, O12E, TTA37, V1171, and McGHS1 bind principally to ciliated NHBE cells and that their corresponding hag mutant strains no longer associate with cilia. The hag gene product of M. catarrhalis isolate O35E was expressed in the heterologous genetic background of a nonadherent Haemophilus influenzae strain, and quantitative assays revealed that the adherence of these recombinant bacteria to NHBE cultures was increased 27-fold. These experiments conclusively demonstrate that the hag gene product is responsible for the previously unidentified tropism of M. catarrhalis for ciliated NHBE cells.
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Perez Vidakovics ML, Riesbeck K. Virulence mechanisms of Moraxella in the pathogenesis of infection. Curr Opin Infect Dis 2009; 22:279-85. [PMID: 19405217 DOI: 10.1097/qco.0b013e3283298e4e] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Moraxella catarrhalis is an emerging human-specific pathogen responsible for upper and lower respiratory tract infections. Understanding the events in the complex pathogenesis and underlying mechanisms during M. catarrhalis infection is a key to the development of novel therapeutics and vaccines. RECENT FINDINGS Several novel findings have been reported on Moraxella pathogenesis and, in parts, explain how the species stands as a commensal in preschool children and survives in the host. Molecular structures for different adhesins in addition to target ligands with respect to signalling and invasion have been defined. Evasion of the complement system allows Moraxella to survive in the mucosa and by neutralizing [alpha]1-antichymotrypsin the protease activity is increased, resulting in tissue destruction and thus promotion of bacterial attachment. Moraxella-dependent cell activation via immunoglobulin D in addition to toll-like receptors and specific epithelial cell inhibition by cross-linking of carcinoembryonic antigen-related cell adhesion molecule-1 in the early innate immune response and, finally, the ability of M. catarrhalis to form biofilms are other specific research areas of interest. SUMMARY Recent advances have allowed a more detailed picture of the processes involved in bacteria-host cell interactions, the cause of inflammatory processes and specific host defense responses against the intriguing species Moraxella.
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Affiliation(s)
- M Laura Perez Vidakovics
- Division of Medical Microbiology, Department of Laboratory Medicine, University Hospital Malmö, Lund University, Malmö, Sweden
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Balder R, Lafontaine ER. Laboratory Maintenance of Moraxella catarrhalis. ACTA ACUST UNITED AC 2008; Chapter 6:Unit 6B.1. [PMID: 19016443 DOI: 10.1002/9780471729259.mc06b01s11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Moraxella catarrhalis is a Gram-negative bacterium that has recently emerged as the third leading cause of bacterial ear infections in children. This organism is also responsible for a variety of upper respiratory tract illnesses in adults, including approximately 10% of all cases of respiratory exacerbations in patients with chronic obstructive pulmonary disease (COPD). There is interest in studying M. catarrhalis for vaccine development, and this unit provides guidelines for the laboratory maintenance of the organism. The three Basic Protocols presented in this unit describe how to culture and prepare M. catarrhalis cells for use in experiments pertaining to various biological aspects of this important respiratory pathogen.
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Affiliation(s)
- Rachel Balder
- University of Georgia, Department of Infectious Diseases, Athens, Georgia, USA
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Modular arrangement of allelic variants explains the divergence in Moraxella catarrhalis UspA protein function. Infect Immun 2008; 76:5330-40. [PMID: 18678659 DOI: 10.1128/iai.00573-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ubiquitous surface protein A molecules (UspAs) of Moraxella catarrhalis are large, nonfimbrial, autotransporter proteins that can be visualized as a "fuzzy" layer on the bacterial surface by transmission electron microscopy. Previous studies attributed a wide array of functions and binding activities to the closely related UspA1, UspA2, and/or UspA2H protein, yet the molecular and phylogenetic relationships among these activities remain largely unexplored. To address this issue, we determined the nucleotide sequence of the uspA1 genes from a variety of independent M. catarrhalis isolates and compared the deduced amino acid sequences to those of the previously characterized UspA1, UspA2, and UspA2H proteins. Rather than being conserved proteins, we observed a striking divergence of individual UspA1, UspA2, and UspA2H proteins resulting from the modular assortment of unrelated "cassettes" of peptide sequence. The exchange of certain variant cassettes correlates with strain-specific differences in UspA protein function and confers differing phenotypes upon these mucosal surface pathogens.
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Verhaegh SJC, Streefland A, Dewnarain JK, Farrell DJ, van Belkum A, Hays JP. Age-related genotypic and phenotypic differences in Moraxella catarrhalis isolates from children and adults presenting with respiratory disease in 2001-2002. MICROBIOLOGY-SGM 2008; 154:1178-1184. [PMID: 18375810 DOI: 10.1099/mic.0.2007/015057-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Moraxella catarrhalis is generally associated with upper respiratory tract infections in children and lower respiratory tract infections in adults. However, little is known regarding the population biology of isolates infecting these two age groups. To address this, a population-screening strategy was employed to investigate 195 worldwide M. catarrhalis isolates cultured from children (<5 years of age) and adults (>20 years of age) presenting with respiratory disease in the years 2001-2002. Parameters compared included: genotype analysis; autoagglutination/biofilm-forming ability; serum resistance; uspA1, uspA2, uspA2H, hag and mcaP incidence; copB/LOS/ompCD/16S rRNA types; and UspA1/Hag expression. A significant difference in biofilm formation (P=0.002), but not in autoagglutination or serum resistance, was observed, as well as significant differences in the incidence of uspA2- and uspA2H-positive isolates, and the distribution of lipooligosaccharide (LOS) types (P<0.0001 and P=0.01, respectively). Further, a significant decrease in the incidence of Hag expression (for isolates possessing the hag gene) was observed in adult isolates (P=0.001). Both uspA2H and LOS type B were associated with 16S rRNA type 1 isolates only, and two surrogate markers (copB and ompCD PCR RFLP types) for the two major M. catarrhalis 16S rRNA genetic lineages were identified. In conclusion, there are significant differences in phenotype and gene incidence between M. catarrhalis isolates from children and adults presenting with respiratory disease, possibly as a result of immune evasion in the adult age group. Our results should also be useful in the choice of effective vaccine candidates against M. catarrhalis.
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Affiliation(s)
- Suzanne J C Verhaegh
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - André Streefland
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Joy K Dewnarain
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | | | - Alex van Belkum
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - John P Hays
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
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