Concise Review of Veterinary Microbiology (eBook)

S. Fanning, E. S. FitzPatrick, F. C. Leonard, B. K. Markey, P. J. Quinn (Autoren)

eBook Download: EPUB

2015 | 2. Auflage
208 Seiten
Wiley (Verlag)
978-1-118-80269-4 (ISBN)

Infos

Updated to reflect the latest developments in the field, Concise Review of Veterinary Microbiology, 2nd Edition, presents essential information on veterinary microbiology for students and those requiring a refresher on key topics relating to microbial diseases in animals. Morphological, cultural and other descriptive features of pathogenic microorganisms are described, together with their habitats and aetiological roles in disease production in animals and, where appropriate, in the human population.

Key features:
• There are five sections covering bacteriology, mycology, virology, biosecurity and other aspects of infectious diseases
• Provides concise, yet comprehensive information on pathogenic microorganisms of importance in veterinary medicine, the diseases which they cause, their diagnosis and control
• The 79 short chapters in this book include 13 new chapters on antibacterial resistance, structure and function of the immune system, antifungal chemotherapy, antiviral chemotherapy, principles of biosecurity and a number of topics related to the control and prevention of infectious diseases
• This latest edition uses updated nomenclature and includes detailed diagrams now in full colour, and comprehensive tables

P.J. Quinn MVB, PhD, MRCVS is Professor Emeritus, School of Veterinary Medicine, University College Dublin. From 1985 to 2002 he was Professor of Veterinary Microbiology and Parasitology and head of that department. He is a senior co-author of a number of books and co-author of a text on veterinary embryology with E.S. FitzPatrick. In 2006, he was recipient of the Association of Veterinary Teachers and Research Workers outstanding teaching award.
B.K. Markey MVB, PhD, MRCVS, Dip. Stat is a Senior Lecturer in Veterinary Microbiology in the School of Veterinary Medicine, University College Dublin (UCD).  He qualified as a veterinary surgeon in 1985, joining the academic staff of the Department of Veterinary Microbiology and Parasitology, UCD a year later.  He served as Head of Department between 2002 and 2004.  In 2005 he was visiting professor at the College of Life Sciences, Queensland University of Technology, Brisbane.  He has contributed chapters and co-authored several books in the field of veterinary microbiology.
F.C. Leonard MVB, PhD, MRCVS is a Veterinary Surgeon and Senior Lecturer in Veterinary Microbiology in the School of Veterinary Medicine, University College Dublin.  She gained her PhD for research on leptospirosis in dairy cattle, and has been teaching veterinary microbiology since 1997.  Her research interests include zoonotic infections, and antimicrobial resistance.
E.S. Fitzpatrick FIBMS, FRMS is Former Chief Technical Officer in the School of Veterinary Medicine, University College Dublin.  He has taught veterinary anatomy and histology for over 25 years.  His research interests have included the interaction of microbial pathogens with epithelial surfaces, especially of the bovine and equine reproductive tracts.  He is, along with P.J. Quinn, co-author Veterinary Embryology, also published by Wiley Blackwell.
S. Fanning BSc, PhD is Professor of Food Safety and Zoonoses in the School of Public Health, Physiotherapy and Population Science, University College Dublin.  He was awarded a Fulbright Fellowship in 1995 and worked at Baylor College of Medicine, Houston.  His research interests include the application of molecular methods to food safety to aid in the control of zoonotic bacteria and tackling multiple drug resistance in food-borne pathogens. The UCD Centre for Food Safety, which he founded in 2002 and of which he is currently Director, was designated in 2009 as the World Health Organization (WHO) Collaborating Centre for Research, Reference and Training on Cronobacter.

Inhalt

Preface vi

Acknowledgements vi

Abbreviations and definitions vii

About the companion website viii

Section I Introductory Bacteriology

1. Structure of bacterial cells 2

2. Cultivation, preservation and inactivation of bacteria 4

3. Bacterial genetics and genetic variation 6

4. Molecular diagnostic methods 10

5. Laboratory diagnosis of bacterial disease 12

6. Molecular subtyping of bacteria 14

7. Antibacterial agents 18

8. Antimicrobial susceptibility testing 20

9. Bacterial resistance to antimicrobial drugs 22

10. Bacterial infections 24

11. Structure and components of the immune system 26

12. Adaptive immunity 30

13. Protective immune responses against infectious agents 32

Section II Pathogenic Bacteria

14. Staphylococcus species 36

15. Streptococci 38

16. Corynebacterium species and Rhodococcus equi 40

17. Actinobacteria 42

18. Listeria species 46

19. Erysipelothrix rhusiopathiae 47

20. Bacillus species 48

21. Clostridium species 50

22. Mycobacterium species 54

23. Enterobacteriaceae 58

24. Pseudomonas aeruginosa 62

25. Burkholderia mallei and Burkholderia pseudomallei 63

26. Actinobacillus species 64

27. Pasteurella species, Mannheimia haemolytica and Bibersteinia trehalosi 66

28. Histophilus, Haemophilus and Avibacterium species 68

29. Taylorella equigenitalis 70

30. Moraxella bovis 71

31. Francisella tularensis 72

32. Lawsonia intracellularis 73

33. Bordetella species 74

34. Brucella species 76

35. Campylobacter species 80

36. Spirochaetes 82

37. Pathogenic, anaerobic, non-spore-forming Gram-negative bacteria 86

38. Mycoplasmas 88

39. Chlamydiae 92

40. Rickettsiales and Coxiella burnetii 94

Section III Mycology

41. General features of fungi associated with disease in animals 98

42. Dermatophytes 100

43. Aspergillus species 102

44. Yeasts and disease production 104

45. Dimorphic fungi 106

46. Zygomycetes of veterinary importance 108

47. Mycotoxins and mycotoxicoses 110

48. Pathogenic algae and cyanobacteria 114

49. Antifungal chemotherapy 116

Section IV Viruses and Prions

50. Nature, structure and taxonomy of viruses 120

51. Replication of viruses 122

52. Laboratory diagnosis of viral disease 126

53. Antiviral chemotherapy 128

54. Herpesviridae 132

55. Papillomaviridae 136

56. Adenoviridae 138

57. Poxviridae 140

58. Asfarviridae 142

59. Bornaviridae 143

60. Parvoviridae 144

61. Circoviridae 146

62. Astroviridae 147

63. Retroviridae 148

64. Reoviridae 152

65. Orthomyxoviridae 154

66. Paramyxoviridae 156

67. Rhabdoviridae 160

68. Bunyaviridae 162

69. Birnaviridae 163

70. Picornaviridae 164

71. Caliciviridae 166

72. Coronaviridae 168

73. Arteriviridae 170

74. Togaviridae 171

75. Flaviviridae 172

76. Prions 176

Section V Prevention and Control of Infectious Disease

77. Biosecurity 180

78. Vaccination 184

79. Disinfection 188

Appendix: relevant websites 190

Index 191

Textauszug

    3       Bacterial genetics and genetic variation

 

Much of the genetic information in bacteria is contained on a single chromosome located in the cytoplasm of the cell. Bacterial genomes differ in size and express characteristic traits or phenotypes.

Properties of a bacterial cell, including those of veterinary interest such as antimicrobial resistance and virulence, are determined by the microbial genome. The genomic structure consists of three types of genetic information, the chromosome, plasmids and bacteriophages. A typical bacterium consists of a core genome, mainly composed of genes located on the chromosome consisting of double-stranded DNA, and an accessory genome comprising plasmid and bacteriophage DNA. In Escherichia coli K-12, the chromosome is a circular double-stranded DNA molecule of approximately 4.6 × 106 base pairs, containing 157 RNA-encoding genes including ribosomal and transfer RNA along with open reading frames (ORFs) coding for 4,126 bacterial proteins. Bacterial chromosomes typically contain sufficient DNA to encode between 1,000 and 4,000 different genes. Individual genes consist of a starting point, referred to as the start codon and composed of the nucleotides ATG, an ORF and a stop codon (TTA, TAG or TGA).

Although the bacterial chromosome exists free in the cytoplasm, it is compacted through supercoiling and looping of its structure. The central tenets of genetics consist of the expression of a gene from its locus on the chromosome or on a plasmid through transcription (production of messenger RNA or mRNA synthesis) and finally translation, decoding of the mRNA to produce a polypeptide. As the DNA is located in the bacterial cytoplasm, this facilitates the simultaneous transcription and translation of bacterial genes. The gene sequence and its subsequent expression through diverse biochemical pathways accounts for the phenotypic variation observed among bacteria. Recently, these specialized topics have given rise to defined areas of research, referred to as genomics, functional genomics or transcriptomics, and proteomics.

Bacteria replicate by binary fission and the daughter cells produced are usually indistinguishable genetically. Replication of the chromosome in bacteria begins at a specific location referred to as the origin of replication (or origin), at a locus referred to as ori. The two parental strands of the helical DNA unwind under the influence of the enzyme DNA helicase and two identical helical DNA molecules are formed through the action of the replicating enzyme, DNA polymerase. The ends of the newly synthesized strands are joined by DNA ligase, resulting in circular chromosomes.

Transcription and translation, the expression of genetic information

Transcription is an enzyme-mediated process that involves DNA being copied from the positive strand, forming an mRNA molecule. This process is mediated by the enzyme DNA-dependent RNA polymerase that binds to the promoter region of a gene, which is composed of two conserved DNA-binding sites referred to as the –35 and –10 promoter sequences. The two strands of DNA are partially unwound, and locally separate, following which mRNA is synthesized. The information encoded in the mRNA is translated into protein on a ribosome through the involvement of transfer RNA (tRNA), which delivers specific amino acids to the mRNA on the ribosome where the amino acids are enzymatically joined together, forming a peptide bond and extending the polypeptide chain.

Genetic variation may occur following mutation in which a change occurs in the nucleotide sequence of a gene, or by recombination, whereby new groups of genes are introduced into the genome. A stable inheritable alteration in any genome is termed a mutation. A bacterium carrying a mutation is referred to as a mutant. When the original parent and mutant are compared, their genotypes differ and their phenotype may also differ depending on the nature of the mutation. Spontaneous mutations are the result of rare mistakes in DNA replication and occur at a frequency of about one in every 106 cell divisions. Because a gene with altered base pairs may code incorrectly for an amino acid in a protein, the mutation introduced may result in a phenotypic change that may be beneficial or harmful for the organism. Under defined environmental conditions, selected mutations may provide a growth advantage for the mutant over the parent or wild-type bacterium. Mutations can also be experimentally induced by physical, chemical or biological mutagens.

Many viruses that infect animals have RNA genomes which may also undergo mutation. The spontaneous mutation rate associated with these genomes is approximately 1,000-fold higher than that occurring in the host chromosome.

DNA may become damaged following contact with mutagenic chemicals, exposure to UV irradiation and by other means. Different mechanisms are available within the cell to organize the repair of damaged DNA and the choice of the appropriate method depends on the type of damage requiring correction.

Recombination occurs when sequences of DNA from two separate sources are integrated. In bacteria, recombination induces an unexpected inheritable change due to the introduction of new genetic material from a different cell. This new genetic material may be introduced by conjugation, transduction or transformation.

The transfer of genetic material in the form of plasmids of various sizes during conjugation is a complex process that has been extensively studied in the enteric bacterium Escherichia coli. During conjugation, F+ (male) bacteria synthesize a modified pilus, the F or sex pilus. This pilus allows direct contact to occur between the male (F+) and a suitable female (F–) bacterium during the process and provides a conduit through which a plasmid or an F-factor can be transferred. One strand of plasmid DNA is unwound and passed to the recipient female (F–) bacterium in which a complementary strand is later synthesized. Once a new plasmid is formed, the recipient cell is converted into an F+ bacterium. Individual bacteria may contain several different types of compatible plasmids.

Plasmid transfer by conjugation has important ecological significance, particularly when antibiotic resistance-encoding genes are involved. A plasmid containing an antibiotic resistance gene in a bacterial cell can, under appropriate conditions, convert the amenable bacterial population into similar plasmid-containing bacterial cells.

DNA acquired either from the original bacterial chromosome or plasmid in a previously infected bacterial cell can be incorporated into phage nucleic acid and transferred by progeny of the phage to susceptible recipient cells in a process called transduction.

Transformation is a process involving the transfer of free or ‘naked’ DNA containing genes on a segment of chromosomal or plasmid DNA from a lysed donor bacterium to a competent recipient. Natural transformation is uncommon and occurs only in a few bacterial genera.

Examples of mobile genetic elements

Plasmids

Although most bacteria carry all the genes necessary for survival on their chromosome, many bacteria contain small additional genetic elements, termed plasmids, which are also located in the cytoplasm and can replicate independently of the host chromosome. Many different plasmids are known in Gram-positive and Gram-negative bacteria. Most are closed, circular, double-stranded DNA molecules but some linear plasmids have been identified in bacteria. Depending on their genetic content, the size of a plasmid can vary from 1 kbp to more than 1 Mbp. Plasmids can carry genes that confer a wide variety of properties on the host bacterial cell. Most are not essential for normal survival of the bacterium, but they may offer a selective advantage under certain conditions, such as the ability to conjugate and transfer genetic information, encode resistance to antibiotics, produce bacteriocins and synthesize proteins inhibitory to other bacteria (Table 3.1). All plasmids carry the genes required for their stable maintenance. In some pathogenic bacteria, plasmids encode virulence factors and antibiotic resistance.

Table 3.1 Virulence factors of pathogenic bacteria encoded by defined genetic elements.

Pathogen

Virulence factors / Genetic elements

Bacillus anthracis

Toxins, capsule / plasmids

Clostridium botulinum, types C, D and E

Neurotoxins / bacteriophages

Escherichia coli

Shiga-like toxin / bacteriophage Adherence factors, enterotoxins / plasmids Heat-stable toxin, siderophore production / transposons

Salmonella Dublin

Serum resistance factor / plasmid

Staphylococcus aureus

Enterotoxins (A, D, E), toxic shock syndrome factor-1 / bacteriophages Coagulase, exfoliating toxins, enterotoxins / plasmids

Yersinia pestis

Fibrinolysin, coagulase / plasmid

Plasmids that can...

Produkt-Details

• Erscheint lt. Verlag: 27.7.2015
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie
• Themenwelt: Veterinärmedizin ► Klinische Fächer ► Mikrobiologie / Immunologie
• Themenwelt: Veterinärmedizin ► Klinische Fächer ► Parasitologie
• Schlagworte: Mikrobiologie • Veterinärmedizin • Veterinärmedizinische Mikrobiologie • Veterinärmedizin / Mikrobiologie,Parasitologie,Infektionen,Immunologie • Veterinärmedizin • Veterinärmedizinische Mikrobiologie • Veterinärmedizin / Mikrobiologie,Parasitologie,Infektionen,Immunologie • Veterinary Medicine • Veterinary Microbiology, Parasitology,Infectious Diseases & Immunology
• ISBN-10: 1-118-80269-1 / 1118802691
• ISBN-13: 978-1-118-80269-4 / 9781118802694