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European Respiratory Review : An... Sep 2019Bronchiectasis is increasing in prevalence worldwide, yet current treatments available are limited to those alleviating symptoms and reducing exacerbations. The... (Review)
Review
Bronchiectasis is increasing in prevalence worldwide, yet current treatments available are limited to those alleviating symptoms and reducing exacerbations. The pathogenesis of the disease and the inflammatory, infective and molecular drivers of disease progression are not fully understood, making the development of novel treatments challenging. Understanding the role bacteria play in disease progression has been enhanced by the use of next-generation sequencing techniques such as 16S rRNA sequencing. The microbiome has not been extensively studied in bronchiectasis, but existing data show lung bacterial communities dominated by , and , while exhibiting intraindividual stability and large interindividual variability. and -dominated microbiomes have been shown to be linked to severe disease and frequent exacerbations. Studies completed to date are limited in size and do not fully represent all clinically observed disease subtypes. Further research is required to understand the microbiomes role in bronchiectasis disease progression. This review discusses recent developments and future perspectives on the lung microbiome in bronchiectasis.
Topics: Animals; Anti-Bacterial Agents; Bronchiectasis; Disease Progression; Haemophilus; Host-Pathogen Interactions; Humans; Lung; Microbiota; Pseudomonas; Risk Factors; Streptococcus
PubMed: 31484665
DOI: 10.1183/16000617.0048-2019 -
Frontiers in Cellular and Infection... 2011Autotransporters are a large class of proteins that are found in the outer membrane of Gram-negative bacteria and are almost universally implicated in virulence. These... (Review)
Review
Autotransporters are a large class of proteins that are found in the outer membrane of Gram-negative bacteria and are almost universally implicated in virulence. These proteins consist of a C-terminal β-domain that is embedded in the outer membrane and an N-terminal domain that is exposed on the bacterial surface and is endowed with effector function. In this article, we review and compare the structural and functional characteristics of the Haemophilus influenzae IgA1 protease and Hap monomeric autotransporters and the H. influenzae Hia and Hsf trimeric autotransporters. All of these proteins play a role in colonization of the upper respiratory tract and in the pathogenesis of H. influenzae disease.
Topics: Adhesins, Bacterial; Bacterial Adhesion; Bacterial Outer Membrane Proteins; Haemophilus Infections; Haemophilus influenzae; Humans; Models, Molecular; Protein Structure, Quaternary; Protein Structure, Tertiary; Serine Endopeptidases; Virulence
PubMed: 22919571
DOI: 10.3389/fcimb.2011.00005 -
The FEBS Journal Feb 2014The glycerophosphodiester phosphodiesterases are evolutionarily conserved proteins that have been linked to several patho/physiological functions, comprising bacterial... (Review)
Review
The glycerophosphodiester phosphodiesterases are evolutionarily conserved proteins that have been linked to several patho/physiological functions, comprising bacterial pathogenicity and mammalian cell proliferation or differentiation. The bacterial enzymes do not show preferential substrate selectivities among the glycerophosphodiesters, and they are mainly dedicated to glycerophosphodiester hydrolysis, producing glycerophosphate and alcohols as the building blocks that are required for bacterial biosynthetic pathways. In some cases, this enzymatic activity has been demonstrated to contribute to bacterial pathogenicity, such as with Hemophilus influenzae. Mammalian glyerophosphodiesterases have high substrate specificities, even if the number of potential physiological substrates is continuously increasing. Some of these mammalian enzymes have been directly linked to cell differentiation, such as GDE2, which triggers motor neuron differentiation, and GDE3, the enzymatic activity of which is necessary and sufficient to induce osteoblast differentiation. Instead, GDE5 has been shown to inhibit skeletal muscle development independent of its enzymatic activity.
Topics: Animals; Cell Differentiation; Escherichia coli; Haemophilus influenzae; Humans; Phosphoric Diester Hydrolases; Substrate Specificity
PubMed: 24373430
DOI: 10.1111/febs.12699 -
Microbiological Reviews Dec 1989The etiological agent of the sexually transmitted genital ulcer disease chancroid was first described in 1889 by Auguste Ducrey following repeated autoinoculation of... (Review)
Review
The etiological agent of the sexually transmitted genital ulcer disease chancroid was first described in 1889 by Auguste Ducrey following repeated autoinoculation of purulent ulcer material from a series of patients. The organism was isolated on artificial media a decade later but has remained difficult to isolate consistently, resulting in controversy over its characteristics and role as the causative agent of chancroid. Because of its fastidious growth requirements, including unknown components in blood, the organism was included in the original description of the genus Haemophilus. Requirement for exogenous hemin and limited phenotypic characteristics, including structural and antigenic properties, suggested that Haemophilus ducreyi was a valid member of the genus Haemophilus. Recent studies of respiratory quinones, deoxyribonucleic acid hybridization, and competition for homologous transformation of the type species, H. influenzae, suggest that H. ducreyi is unrelated to any of the present species of the family Pasteurellaceae, which includes members of the genera Haemophilus, Actinobacillus, and Pasteurella. This review summarizes the early studies with H. ducreyi and our current knowledge of the microbiology of this important human pathogen.
Topics: Chancroid; Haemophilus ducreyi; Humans; Microscopy, Electron
PubMed: 2687678
DOI: 10.1128/mr.53.4.377-389.1989 -
Revista Chilena de Infectologia :... Dec 2013
Topics: Haemophilus influenzae
PubMed: 24522312
DOI: 10.4067/S0716-10182013000600015 -
Critical Reviews in Microbiology Mar 2021is the most common cause of bacterial infection in the lungs of chronic obstructive pulmonary disease (COPD) patients and contributes to episodes of acute exacerbation... (Review)
Review
is the most common cause of bacterial infection in the lungs of chronic obstructive pulmonary disease (COPD) patients and contributes to episodes of acute exacerbation which are associated with increased hospitalization and mortality. Due to the ability of to adhere to host epithelial cells, initial colonization of the lower airways can progress to a persistent infection and biofilm formation. This is characterized by changes in bacterial behaviour such as reduced cellular metabolism and the production of an obstructive extracellular matrix (ECM). Herein we discuss the multiple mechanisms by which contributes to the pathogenesis of COPD. In particular, mechanisms that facilitate bacterial adherence to host airway epithelial cells, biofilm formation, and microbial persistence through immune system evasion and antibiotic tolerance will be discussed.
Topics: Animals; Bacterial Adhesion; Haemophilus Infections; Haemophilus influenzae; Humans; Lung; Pulmonary Disease, Chronic Obstructive
PubMed: 33455514
DOI: 10.1080/1040841X.2020.1863330 -
Frontiers in Cellular and Infection... 2012Haemophilus influenzae is a commensal of the human upper respiratory tract. H. influenzae can, however, move out of its commensal niche and cause multiple respiratory... (Review)
Review
Haemophilus influenzae is a commensal of the human upper respiratory tract. H. influenzae can, however, move out of its commensal niche and cause multiple respiratory tract diseases. Such diseases include otitis media in young children, as well as exacerbations of chronic obstructive pulmonary disease (COPD), sinusitis, conjunctivitis, and bronchitis. During the course of colonization and infection, H. influenzae must withstand oxidative stress generated by multiple reactive oxygen species produced endogenously, by other co-pathogens and by host cells. H. influenzae has, therefore, evolved multiple mechanisms that protect the cell against oxygen-generated stresses. In this review, we will describe these systems relative to the well-described systems in Escherichia coli. Moreover, we will compare how H. influenzae combats the effect of oxidative stress as a necessary phenotype for its roles as both a successful commensal and pathogen.
Topics: Haemophilus influenzae; Humans; Oxidative Stress; Reactive Oxygen Species; Stress, Physiological
PubMed: 22919631
DOI: 10.3389/fcimb.2012.00040 -
The European Respiratory Journal Oct 2021
Topics: Haemophilus; Haemophilus influenzae; Humans; Inflammation; Interleukin-6; Pulmonary Disease, Chronic Obstructive
PubMed: 34649972
DOI: 10.1183/13993003.02143-2021 -
The Western Journal of Medicine Feb 1978Ampicillin-resistant Hemophilus influenzae had not been identified in Fresno, California, before June 1976. In the 12 months that followed, eight resistant type B...
Ampicillin-resistant Hemophilus influenzae had not been identified in Fresno, California, before June 1976. In the 12 months that followed, eight resistant type B strains and three resistant nontypable isolates were cultured from patients treated at two hospitals that provide nearly all of the acute pediatric inpatient care for the area. Two of the resistant strains were obtained from patients with invasive infections and represented 4.2 percent of Hemophilus influenzae isolated from blood, cerebrospinal fluid or joint aspirates during the 12 months. The remaining six resistant type B strains were obtained from 117 patients, and were the predominant organism in cultures of other sites, primarily respiratory secretions. In two of three patients infected with nontypable organisms, resistance appeared to emerge during therapy with ampicillin. Measurement of beta lactamase was a practical and accurate method for differentiating between ampicillin-sensitive and resistant strains. All ten of the beta lactamase-positive isolates tested had minimal inhibitory concentrations (MIC) for ampicillin of 15 mug per ml, or less. In contrast 30 beta lactamase-negative strains had MIC's of 1.5 mug per ml, or less, of ampicillin. Our results indicate that ampicillin resistance has become a significant problem in the Central Valley of California and probably the entire state.
Topics: Adolescent; Ampicillin; California; Child; Haemophilus influenzae; Humans; Infant; Middle Aged; Penicillin Resistance
PubMed: 305157
DOI: No ID Found -
International Microbiology : the... Dec 2012The human respiratory tract contains a highly adapted microbiota including commensal and opportunistic pathogens. Noncapsulated or nontypable Haemophilus influenzae... (Review)
Review
The human respiratory tract contains a highly adapted microbiota including commensal and opportunistic pathogens. Noncapsulated or nontypable Haemophilus influenzae (NTHi) is a human-restricted member of the normal airway microbiota in healthy carriers and an opportunistic pathogen in immunocompromised individuals. The duality of NTHi as a colonizer and as a symptomatic infectious agent is closely related to its adaptation to the host, which in turn greatly relies on the genetic plasticity of the bacterium and is facilitated by its condition as a natural competent. The variable genotype of NTHi accounts for its heterogeneous gene expression and variable phenotype, leading to differential host-pathogen interplay among isolates. Here we review our current knowledge of NTHi diversity in terms of genotype, gene expression, antigenic variation, and the phenotypes associated with colonization and pathogenesis. The potential benefits of NTHi diversity studies discussed herein include the unraveling of pathogenicity clues, the generation of tools to predict virulence from genomic data, and the exploitation of a unique natural system for the continuous monitoring of long-term bacterial evolution in human airways exposed to noxious agents. Finally, we highlight the challenge of monitoring both the pathogen and the host in longitudinal studies, and of applying comparative genomics to clarify the meaning of the vast NTHi genetic diversity and its translation to virulence phenotypes.
Topics: Adaptation, Biological; Antigenic Variation; Gene Expression; Genetic Variation; Genotype; Haemophilus Infections; Haemophilus influenzae; Humans; Phenotype; Respiratory System; Respiratory Tract Infections; Virulence
PubMed: 23844475
DOI: 10.2436/20.1501.01.169