Pasteurellaceae: Biology, Genomics and Molecular Aspects | Book
Caister Academic Press
and Henrik Christensen2
1Institute of Veterinary Bacteriology, Vetsuisse Faculty University of Bern, Länggass-Str. 122, 3001 Bern, Switzerland and 2Department of Veterinary Pathobiology, Faculty of Life Science, Copenhagen University, Dyrlaegevej 88, 1870 Frederiksberg, Denmark
viii + 267
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Pasteurellaceae comprise a large and diverse family of Gram-negative bacteria with members ranging from important pathogens such as Haemophilus influenzae to commensals of the animal and human mucosa. Information on the biology of these organisms has mushroomed in recent years, driven by the development of novel genetic and molecular methodologies. Since 1995, the family has been expanded from three genera to the current thirteen through the use of new genetic-based classification and identification technologies. Many members of the Pasteurellaceae family make excellent natural models for the study of bacterial pathogenesis and host-pathogen-interactions thus giving valuable insights into related human diseases. Research in this area is at a very exciting stage. In this timely book, leading international Pasteurellaceae scientists critically review the most important current research providing an up-to-date review of the molecular biology, genomics and virulence of these fascinating organisms. Topics covered include taxonomy and biodiversity, phylogeny, comparative genomics, competence, DNA uptake and transformation, proteomics and protein secretion, RTX toxins, lipopolysaccharides, biofilms, quorum sensing, antimicrobial resistance, diagnosis, and OMP and iron uptake. Each chapter is independent and can be read in isolation and as a whole the book provides an important resource summarising our current knowledge of Pasteurellaceae genomics and molecular biology. Essential reading for everyone working on Pasteurellaceae and related organisms.
"This broad overview of many aspects of the family Pasteurellaceae provides excellent coverage of the current status of taxonomy and phylogeny of this diverse group of bacteria. ... This is a much needed information resource for researchers. ... This is a rich source of information and provides well balanced coverage of relevant topics. It is a comprehensive guide that provides critical insight into the current understanding of molecular and genomic aspects of Pasteurellaceae." from Doodys (2009)
"The book covers a broad remit with its field ... well-written and covering the various areas very well" from Microbiology Today (2009)
Table of contents
1 . Taxonomy and biodiversity of members of Pasteurellaceae
Henrik Christensen and Magne Bisgaard
The family Pasteurellaceae Pohl 1981 includes 38 properly classified species in addition to 24 misclassified species. The majority of taxa have been isolated from disease conditions in warm blooded animals and in particular in farm animals. These bacteria are obligate parasites or commensals of vertebrates, colonizing mainly the mucosal surfaces of the upper respiratory tract, oropharynx, and reproductive tracts and possibly also parts of the intestinal tract. Most taxa represent potential pathogens although mechanisms of virulence have remained unknown or doubtful until recent years. Both systemic and local infections have been reported for most taxa involved in diseases. However, pneumonia has been reported most frequently out of a number of other disease manifestations. Fossil remnants of members of Pasteurellaceae have never been reported and information on the diversification of taxa within the family can only be obtained by phylogenetic reconstruction. Most likely the current members of Pasteurellaceae might have been present as common ancestors of for example birds and dinosaurs. For marsupials, monotremes and reptiles information is very limited and further insight from these groups would be very helpful to test the hypothesis of co-evolution of host and parasite.
2 . Phylogeny of Pasteurellaceae
Bozena M. Korczak and Peter Kuhnert
This chapter provides an overview on the DNA based phylogeny of the family Pasteurellaceae and the genetic relatedness between taxa taking into account the various gene targets and approaches applied in the literature. The classical 16S rRNA gene based phylogeny as well as phylogenies based on house-keeping genes are described. Moreover, strength and weakness of the different trees and their topology are discussed based on the phylogenetic groups resolved. The data should help to get a clearer picture on the recent, current and future classification and also provide information to genetic characterization of members of the family. The history of phylogeny applied to the family as well as the phylogenetic history of the family is thereby presented. In this way it is the story of the search for the optimal phylogenetic marker without giving a final conclusive suggestion but it is also a resource for choosing the appropriate gene target(s) for people investigating the phylogeny of groups of Pasteurellaceae.
3 . Comparative Genomics of Pasteurellaceae
Jean F. Challacombe and Thomas J. Inzana
The family Pasteurellaceae contains diverse members, including opportunistic pathogens, human and animal pathogens as well as avirulent commensal strains. Although they are related, the diversity of the bacteria comprising this family makes them ideal candidates for comparative genome analysis. In this chapter we review and compare the available genomic information on the sequenced Pasteurellaceae members: Aggregatibacter actinomycetemcomitans strain HK1651, Actinobacillus pleuropneumoniae strains L20 and sv1 4074, [ Haemophilus ] ducreyi strain 35000HP, Haemophilus influenzae strains 86-028NP, R2846, R2866, and Rd, Histophilus somni strains 129Pt and 2336, Mannheimia haemolytica A1 strain ATCC BAA-410, ' Mannheimia succiniciproducens ' strain MBEL55E, and Pasteurella multocida strain Pm70. We also present some example comparisons to demonstrate the utility of the comparative genomics approach for studying this family of bacteria.
4 . Competence, DNA Uptake and Transformation in Pasteurellaceae
Heather Maughan, Sunita Sinha, Lindsay Wilson and Rosemary Redfield
The ability to take up DNA from the environment and recombine it into the chromosome appears to be ancestral to the Pasteurellaceae, although only some isolates do this efficiently under laboratory conditions. Studies of readily transformable isolates have shown that competence for DNA uptake is regulated by the cyclic AMP-dependent regulatory protein CRP and by Sxy, a competence-specific transcriptional activator. Once cells are competent, DNA uptake is promoted by recognition of an uptake signal sequence motif that is highly over-represented in the genomes of all Pasteurellaeae, including those that cannot be transformed. Transport of the DNA across the cell envelope uses components of the type 4 pilus machinery, homologous to those used by other naturally competent bacteria. Once in the cytoplasm this DNA may be degraded or, if sequence similarity permits, it may be recombined into the chromosome. Although such recombination can have important evolutionary consequences, DNA uptake is likely to serve primarily as a source of nucleotides for the cell.
5 . Proteomic analyses in Pasteurellaceae
John D. Boyce and Ben Adler
Proteomics is the simultaneous identification and/or analysis of large groups of proteins expressed by an organism. Here we review the range of proteomic analyses which have been reported for members of the family Pasteurellaceae. These include the non-quantitative identification of proteins from whole organisms or from sub-cellular fractions, as well as the quantitative analysis of how the expression of certain proteins changes in response to particular growth conditions. As many members of the Pasteurellaceae are important pathogens, studies have focussed primarily on protein expression under conditions likely to be encountered during natural infections. The large variation in experimental techniques used and the conditions analysed has made it difficult to make meaningful comparisons about protein expression across the species within the Pasteurellaceae.
6 . Protein Secretion in Pasteurellaceae
Scott C. Kachlany and Nataliya V. Balashova
Protein secretion is an essential process for all cells. Gram negative bacteria use different secretion systems to transport a variety of proteins across their double membrane and into the extracellular environment. In general, bacterial protein secretion systems are complex machineries made up of many components that act together to transport molecules out of the cell. There are essentially three classes of proteins that the members of the Pasteurellaceae secrete: Toxins, Adhesins, and Proteases. Toxins produced by the members of the Pasteurellaceae include the highly host-specific RTX toxins and cytolethal distending toxins. Adhesins include the self-secreting autotransporters, the widespread Flp pili, and type IV pili. The proteases produced by these members include the antibody-cleaving immunoglobulin and bi-functional HAP proteases.
7 . RTX Toxin Determined Virulence of Pasteurellaceae
RTX toxins are bacterial pore forming toxins that are particularly abundant among pathogenic species of Pasteurellaceae where they play a major role in virulence. RTX toxins of several primary pathogens of the family of Pasteurellaceae are directly involved in causing necrotic lesions of the target organs. Many RTX toxins are mainly known as haemolysins due to their capacity to lyse erythrocytes in vitro, an effect that seems to be non-specific. It is now known for many RTX toxins that their specific targets are leukocytes, where RTX toxins bind to the corresponding β subunit (CD18) of β2 integrons and then cause a cytotoxic effect. For several RTX toxins the binding to CD18 was shown to be host specific and seems to be the basis determining the host range of a given RTX toxin. Observations on very closely related species of the Pasteurellaceae family with different RTX toxins indicate that these latter contribute to a significant part to the host specificity of the pathogen itself. RTX toxins induce a strong immunologic response generating neutralizing antibodies. They therefore constitute important antigens in modern subunit vaccines.
8 . Outer Membrane Proteins and Iron Uptake of Actinobacillus pleuropneumoniae
Jacqueline W. Chung, Mario Jacques and James W. Coulton
Essential for the integrity and selective permeability of the membrane, outer membrane (OM) proteins of Gram-negative bacteria have critical roles in adaptation and infection within a host niche. With prominent roles in the pathogenesis of several bacterial pathogens, OM proteins have growing appeal as novel targets for anti-infectives and therapeutics. Members of the Pasteurellaceae family represent important human and animal pathogens that include Haemophilus , Actinobacillus , Pasteurella , and more recently, the newly added Mannheimia genera of organisms. Characterization of cell surface proteins has highlighted several redundant iron acquisition receptors for transferrin, siderophores, and heme/heme-containing proteins in Pasteurellaceae. In addition, the identification of several immunogenic lipoproteins and OM proteins has driven research for an effective cross-protective vaccine for these organisms. This chapter will review OM proteins and iron uptake systems of the swine pathogen, Actinobacillus pleuropneumoniae , causative agent of porcine pleuropneumonia, with reference to homologues in other members of Pasteurellaceae.
9 . Lipopolysaccharides, Biofilms, and Quorum Sensing in Pasteurellaceae
Thomas J. Inzana, W. Edward Swords, Indra Sandal, and Shivakumara Siddaramappa
The endotoxin of the Pasteurellaceae is an essential component of the bacterial cell surface, as it is for all gram-negative bacteria. However, the Pasteurellaceae are unusual in that some members make an endotoxin that is a lipopolysaccharide (LPS) while others make a lipooligosaccharide (LOS). The LOS can be a relatively simple antigen, or a deceptively complex molecule that can be decorated with a variety of components that influence host response and interactions, contain structures that mimic host antigens, and phase vary in the expression of these antigenic epitopes. In this chapter, we will give a brief summary of what is known regarding LPS/LOS structure and genetics for different members of the Pasteurellaceae, and discuss how the glycose and other associated components affect persistence and virulence in vivo . Furthermore, we will discuss the formation of biofilms, which are produced by many members of this group, and how these surface-attached biofilm communities may promote bacterial persistence in vivo, even in the face of immune effectors and antimicrobial treatment. Finally, we will describe a related field of bacterial quorum sensing, which is an area of much recent work for these and other bacterial species.
10 . Mechanisms of Antimicrobial Resistance in Pasteurellaceae
Members of the family Pasteurellaceae cause a wide variety of diseases in humans and animals. Antimicrobial agents represent the most powerful tools to control such infections. Acquisition of resistance genes as well as development of resistance-mediating mutations, however, strongly reduce the efficacy of the antimicrobial agents. In this chapter, a review of the current knowledge of the genetic basis of resistance to antimicrobial agents is given with particular reference to resistances to β-lactam antibiotics, tetracyclines, amino-glycosides/aminocyclitols, phenicols, sulfonamides, trimethoprim, macrolides, and quinolones. Moreover, the role of plasmids and transposons in the spread of the resistance genes among Pasteurellaceae and members of other bacterial families is highlighted to provide insight into the possibilities of horizontal dissemination, co-selection and persistence of antimicrobial resistance genes.
11 . Pasteurellaceae: The View from the Diagnostic Laboratory
Pat Blackall and Niels Nørskov-Lauritsen
This chapter provides a centralised, organised overview of the isolation and identification of those members of the Pasteurellaceae that are commonly encountered in the clinical and veterinary diagnostic laboratories. The chapter covers both traditional methodologies as well as the modern molecular methods. Where possible, alternative methods are critically reviewed and recommendations on which methods are relevant for particular applications are provided. The chapter does not provide detailed methodologies but does provide identification tables that laboratories using the phenotypic identification approach should find useful.
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(EAN: 9781904455349 Subjects: [bacteriology] [microbiology] [medical microbiology] [molecular microbiology] [genomics] )