The HMW1 and HMW2 Adhesins Enhance the Ability of Nontypeable Haemophilus influenzae To Colonize the Upper Respiratory Tract of Rhesus Macaques

NontypeableHaemophilus influenzae(NTHi) initiates infection by colonizing the upper respiratory tract and is a common cause of localized respiratory tract disease. Previous work has established that the NTHi HMW1 and HMW2 proteins are potent adhesins that mediate efficientin vitroadherence to cultured human respiratory epithelial cells. In this study, we used a rhesus macaque model to assess the contributions of HMW1 and HMW2 toin vivocolonization. In experiments involving inoculation of individual isogenic derivatives of NTHi strain 12, the parent strain expressing both HMW1 and HMW2 and the mutant strains expressing either HMW1 or HMW2 were able to colonize more frequently than the double mutant strain lacking HMW1 and HMW2. In competition experiments, the parent strain efficiently outcompeted the double mutant lacking HMW1 and HMW2. Colonization with strains expressing HMW2 resulted in development of antibody against HMW2 in a number of the animals, demonstrating that colonization can stimulate an antibody response. In conclusion, we have established that the HMW1 and HMW2 adhesins play a major role in facilitating colonization of the upper respiratory tract of rhesus macaques, in some cases associated with stimulation of an immune response.

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VapC-1 of Nontypeable Haemophilus influenzae Is a Ribonuclease

Journal of Bacteriology ◽

10.1128/jb.00290-07 ◽

2007 ◽

Vol 189 (14) ◽

pp. 5041-5048 ◽

Cited By ~ 52

Author(s):

Dayle A. Daines ◽

Mack H. Wu ◽

Sarah Y. Yuan

Keyword(s):

Haemophilus Influenzae ◽

Growth Inhibition ◽

Gene Pair ◽

Gene Families ◽

Upper Respiratory Tract ◽

Nontypeable Haemophilus Influenzae ◽

E Coli ◽

Conserved Gene

ABSTRACT Nontypeable Haemophilus influenzae (NTHi) organisms are obligate parasites of the human upper respiratory tract that can exist as commensals or pathogens. Toxin-antitoxin (TA) loci are highly conserved gene pairs that encode both a toxin and antitoxin moiety. Seven TA gene families have been identified to date, and NTHi carries two alleles of the vapBC family. Here, we have characterized the function of one of the NTHi alleles, vapBC-1. The gene pair is transcribed as an operon in two NTHi clinical isolates, and promoter fusions display an inverse relationship to culture density. The antitoxin VapB-1 forms homomultimers both in vitro and in vivo. The expression of the toxin VapC-1 conferred growth inhibition to an Escherichia coli expression strain and was successfully purified only when cloned in tandem with its cognate antitoxin. Using total RNA isolated from both E. coli and NTHi, we show for the first time that VapC-1 is an RNase that is active on free RNA but does not degrade DNA in vitro. Preincubation of the purified toxin and antitoxin together results in the formation of a protein complex that abrogates the activity of the toxin. We conclude that the NTHi vapBC-1 gene pair functions as a classical TA locus and that the induction of VapC-1 RNase activity leads to growth inhibition via the mechanism of mRNA cleavage.

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Antiviral Properties of Food Plants Could Help to Reduce Contagion and Severity in SARS-CoV-2 Infections

Current Traditional Medicine ◽

10.2174/2215083807666210917144039 ◽

2021 ◽

Vol 07 ◽

Author(s):

Betina Cardoso

Keyword(s):

Respiratory Tract ◽

Literature Search ◽

Food Plants ◽

Upper Respiratory Tract ◽

Site Specific ◽

In Vivo Experiments ◽

Upper Respiratory ◽

Novel Coronavirus

Introduction: The importance of an immediate tool to help patients and prevent viral diffusion of new pneumonia caused by 2019 novel coronavirus (2019-nCoV or SARS-CoV-2) that causes the disease COVID-19 becomes evident. Recent articles have reported on body site-specific SARS-CoV-2 infection, showing very active replication in the throat and upper respiratory tract when symptoms were still mild, and thus being efficient in viral transmission in sputum. Material and Methods: An alternative that may be feasible is to resort to scientific studies that demonstrate the antiviral potential of medicinal plants species through in-vitro and in-vivo experiments to alleviate symptoms and prevent the spread of contagion. A literature search in Scopus and PubMed on herbs and foods with antiviral properties was performed. Results: Herbs and foods with demonstrated antiviral potential have been identified, which could limit SARS-CoV-2 spreading by interfering on ACE2 protein on infection sites. The analysis of transdisciplinary knowledge allows us to connect previous research on the action of common plants and foods on viruses to limit the replication of SARS-CoV-2 in the throat and upper respiratory tract. Conclusions: Herbs and foods with demonstrated antiviral potential have been identified, which could limit SARS-CoV-2 spreading by interfering on ACE2 protein on infection sites. The analysis of transdisciplinary knowledge allows us to connect previous research on the action of common plants and foods on viruses to limit the replication of SARS-CoV-2 in the throat and upper respiratory tract.

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A rat nasal epithelial model for predicting upper respiratory tract toxicity: in vivo–in vitro correlations

Toxicology ◽

10.1016/s0300-483x(99)00180-8 ◽

2000 ◽

Vol 145 (1) ◽

pp. 39-49 ◽

Cited By ~ 8

Author(s):

J.D Kilgour ◽

S.A Simpson ◽

D.J Alexander ◽

C.J Reed

Keyword(s):

Respiratory Tract ◽

Upper Respiratory Tract ◽

Upper Respiratory

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Demonstration of N , N -Dimethyldithiocarbamate as a Copper-Dependent Antibiotic against Multiple Upper Respiratory Tract Pathogens

Microbiology Spectrum ◽

10.1128/spectrum.00778-21 ◽

2021 ◽

Author(s):

Sanjay V. Menghani ◽

Angela Rivera ◽

Miranda Neubert ◽

James R. Hagerty ◽

Lourdes Lewis ◽

...

Keyword(s):

Antibiotic Resistance ◽

Streptococcus Pneumoniae ◽

Respiratory Tract ◽

Dependent Manner ◽

Upper Respiratory Tract ◽

Coccidioides Posadasii ◽

Content Type ◽

Upper Respiratory

With the rise of antibiotic resistance, approaches that add new antimicrobials to the current repertoire are vital. Here, we investigate putative and known copper ionophores in an attempt to intoxicate bacteria and use ionophore/copper synergy, and we ultimately find success with N , N -dimethyldithiocarbamate (DMDC). We show that DMDC has in vitro efficacy in a copper-dependent manner and kills pathogens across three different kingdoms, Streptococcus pneumoniae ( Sr. pneumoniae ), Coccidioides posadasii , and Schistosoma mansoni , and in vivo efficacy against Sr . pneumoniae .

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Cross-sectional study of adenoidal biofilms in a paediatric population and its clinical implications

Otolaryngologia Polska ◽

10.5604/01.3001.0012.5278 ◽

2018 ◽

Vol 72 (5) ◽

pp. 1-5

Author(s):

Joao Subtil ◽

Maria Paula Bajanka-Lavado ◽

Joao Rodrigues ◽

Aida Duarte ◽

Lucia Reis ◽

...

Keyword(s):

Respiratory Tract ◽

Clinical Sample ◽

Paediatric Population ◽

Cross Sectional Study ◽

Upper Respiratory Tract ◽

Cross Sectional ◽

Relevant Role ◽

Upper Respiratory

INTRODUCTION: Adenoids are nasopharyngeal lymphoid tissue with a relevant role in host defence against infection of upper respiratory tract. Nevertheless, adenoids are also a reservoir of microorganisms that can cause infections of upper respiratory tract and otitis particularly in children. OBJECTIVE: Evaluate and compare the association between biofilm assembly on adenoids and the incidence of recurrent infections in a paediatric population submitted to adenoidectomy by either infectious or non-infectious indication. METHODS: Scanning electron microscopy was used to assess biofilms on adenoid surface; biofilm assembly in vitro was monitored by crystal violet assay; antibiotic susceptibility was assessed following EUCAST guidelines; Hinfluenzae capsular typing was performed by PCR. RESULTS: Biofilms were present in 27.4% of adenoid samples and no statistical difference was found between infectious and non-infectious groups. In vitro, the most clinically relevant bacteria, H.influenzae, S.aureus, S.pyogenes, S.pneumoniae and M.catarrhalis, were mostly moderate biofilm assemblers (71.7%). 55.3% of these bacteria were intermediate/resistant to at least one of the tested antibiotics. No association was found between the ability to assemble biofilms in vitro and the presence of biofilms on adenoids nor antibiotic resistance. All H.influenzae were characterized as non-typeable. CONCLUSION: The presence of biofilms on adenoid surface was independent from clinical sample background. Bacterial ability to assemble biofilms in vitro cannot be used to predict biofilm assembly in vivo. The lack of correlation between biofilm formation and infectious respiratory diseases found contributes to question the relevance of biofilms on the pathogenesis of infectious diseases.

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Comparison of In Vitro Deposition of Pharmaceutical Aerosols in an Idealized Child Throat with In Vivo Deposition in the Upper Respiratory Tract of Children

Pharmaceutical Research ◽

10.1007/s11095-013-1258-2 ◽

2014 ◽

Vol 31 (6) ◽

pp. 1525-1535 ◽

Cited By ~ 18

Author(s):

Conor A. Ruzycki ◽

Laleh Golshahi ◽

Reinhard Vehring ◽

Warren H. Finlay

Keyword(s):

Respiratory Tract ◽

Upper Respiratory Tract ◽

Pharmaceutical Aerosols ◽

Upper Respiratory

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In Vivo Tropism of Attenuated and Pathogenic Measles Virus Expressing Green Fluorescent Protein in Macaques

Journal of Virology ◽

10.1128/jvi.02633-09 ◽

2010 ◽

Vol 84 (9) ◽

pp. 4714-4724 ◽

Cited By ~ 72

Author(s):

Rory D. de Vries ◽

Ken Lemon ◽

Martin Ludlow ◽

Stephen McQuaid ◽

Selma Yüksel ◽

...

Keyword(s):

Green Fluorescent Protein ◽

Respiratory Tract ◽

Measles Virus ◽

Fluorescent Protein ◽

Lymphoid Tissues ◽

Upper Respiratory Tract ◽

Upper Respiratory ◽

Green Fluorescent

ABSTRACT The global increase in measles vaccination has resulted in a significant reduction of measles mortality. The standard route of administration for the live-attenuated measles virus (MV) vaccine is subcutaneous injection, although alternative needle-free routes, including aerosol delivery, are under investigation. In vitro, attenuated MV has a much wider tropism than clinical isolates, as it can use both CD46 and CD150 as cellular receptors. To compare the in vivo tropism of attenuated and pathogenic MV, we infected cynomolgus macaques with pathogenic or attenuated recombinant MV expressing enhanced green fluorescent protein (GFP) (strains IC323 and Edmonston, respectively) via the intratracheal or aerosol route. Surprisingly, viral loads and cellular tropism in the lungs were similar for the two viruses regardless of the route of administration, and CD11c-positive cells were identified as the major target population. However, only the pathogenic MV caused significant viremia, which resulted in massive virus replication in B and T lymphocytes in lymphoid tissues and viral dissemination to the skin and the submucosa of respiratory epithelia. Attenuated MV was rarely detected in lymphoid tissues, and when it was, only in isolated infected cells. Following aerosol inhalation, attenuated MV was detected at early time points in the upper respiratory tract, suggesting local virus replication. This contrasts with pathogenic MV, which invaded the upper respiratory tract only after the onset of viremia. This study shows that despite in vitro differences, attenuated and pathogenic MV show highly similar in vivo tropism in the lungs. However, systemic spread of attenuated MV is restricted.

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Immunization with HMW1 and HMW2 adhesins protects against colonization by heterologous strains of nontypeable Haemophilus influenzae

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2019923118 ◽

2021 ◽

Vol 118 (32) ◽

pp. e2019923118

Author(s):

Nadia A. Kadry ◽

Eric A. Porsch ◽

Hao Shen ◽

Joseph W. St. Geme

Keyword(s):

Antibody Response ◽

Respiratory Tract ◽

Haemophilus Influenzae ◽

Rhesus Macaques ◽

Critical Role ◽

Upper Respiratory Tract ◽

Nontypeable Haemophilus Influenzae ◽

Nasopharyngeal Colonization ◽

Vaccine Potential ◽

Tract Disease

Nontypeable Haemophilus influenzae (NTHi) is a common cause of localized respiratory tract disease and results in significant morbidity. The pathogenesis of NTHi disease begins with nasopharyngeal colonization, and therefore, the prevention of colonization represents a strategy to prevent disease. The NTHi HMW1 and HMW2 proteins are a family of conserved adhesins that are present in 75 to 80% of strains and have been demonstrated to play a critical role in colonization of the upper respiratory tract in rhesus macaques. In this study, we examined the vaccine potential of HMW1 and HMW2 using a mouse model of nasopharyngeal colonization. Immunization with HMW1 and HMW2 by either the subcutaneous or the intranasal route resulted in a strain-specific antibody response associated with agglutination of bacteria and restriction of bacterial adherence. Despite the specificity of the antibody response, immunization resulted in protection against colonization by both the parent NTHi strain and heterologous strains expressing distinct HMW1 and HMW2 proteins. Pretreatment with antibody against IL-17A eliminated protection against heterologous strains, indicating that heterologous protection is IL-17A dependent. This work demonstrates the vaccine potential of the HMW1 and HMW2 proteins and highlights the importance of IL-17A in protection against diverse NTHi strains.

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Nontypeable Haemophilus influenzae infection impedes Pseudomonas aeruginosa colonization and persistence in mouse respiratory tract

Infection and Immunity ◽

10.1128/iai.00568-21 ◽

2021 ◽

Author(s):

Natalie Lindgren ◽

Lea Novak ◽

Benjamin C. Hunt ◽

Melissa S. McDaniel ◽

W. Edward Swords

Keyword(s):

Pseudomonas Aeruginosa ◽

Respiratory Tract ◽

Haemophilus Influenzae ◽

Respiratory Infections ◽

Bacterial Species ◽

Young Patients ◽

Nontypeable Haemophilus Influenzae ◽

Potential Significance ◽

And Diffusion

Patients with cystic fibrosis (CF) experience lifelong respiratory infections which are a significant cause of morbidity and mortality. These infections are polymicrobial in nature, and the predominant bacterial species undergo a predictable series of changes as patients age. Young patients have populations dominated by opportunists that are typically found within the microbiome of the human nasopharynx, such as nontypeable Haemophilus influenzae (NTHi); these are eventually supplanted and the population within the CF lung is later dominated by pathogens such as Pseudomonas aeruginosa ( Pa ). In this study, we investigated how initial colonization with NTHi impacts colonization and persistence of Pa in the respiratory tract. Analysis of polymicrobial biofilms in vitro by confocal microscopy revealed that NTHi promoted greater levels of Pa biofilm volume and diffusion. However, sequential respiratory infection of mice with NTHi followed by Pa resulted in significantly lower Pa as compared to infection with Pa alone. Coinfected mice also had reduced airway tissue damage and lower levels of inflammatory cytokines as compared with Pa infected mice. Similar results were observed after instillation of heat-inactivated NTHi bacteria or purified NTHi lipooligosaccharide (LOS) endotoxin prior to Pa introduction. Based on these results, we conclude that NTHi significantly reduces susceptibility to subsequent Pa infection, most likely due to priming of host innate immunity rather than a direct competitive interaction between species. These findings have potential significance with regard to therapeutic management of early life infections in patients with CF.

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