Epidemiological and Molecular Aspects on Cholera (eBook)

Preface 5
Contents 7
Contributors 9
1 General Introduction 12
2 Asiatic Cholera: Mole Hills and Mountains 16
2.1 Introduction 16
2.2 Cholera in the Indian Subcontinent 17
2.3 Other Asian Countries 19
2.4 Association Between V. cholerae and Parasites 20
2.5 The O139 Cholera 20
2.6 Antimicrobial Resistance 22
2.7 Phage Typing of V. cholerae O1 and O139 23
2.8 Molecular Epidemiology 24
2.9 Seroepidemiology 27
2.10 Prospects of Cholera Vaccines in Asia 28
2.11 Traditional Medicine and Food Habits for Prevention of Cholera 29
2.12 Control Measures and Health-Care Systems 29
2.13 Conclusion 31
References 31
3 Endemic and Epidemic Cholera in Africa 41
3.1 Introduction 41
3.2 Epidemics and Outbreaks 42
3.3 Risk Factors and Modes of Transmission of Cholera 44
3.4 The Organism 49
3.5 Seroepidemiology 50
3.6 Use of Antimicrobials 50
3.7 Molecular Findings 52
3.8 Strategies to Curtail Cholera Outbreaks 52
3.9 Conclusions 53
References 54
4 Phenotypic and Molecular Characteristics of Epidemic and Non-epidemic Vibrio cholerae Strains Isolated in Russia and Certain Countriesof Commonwealth of Independent States (CIS) 61
4.1 Introduction 61
4.2 Toxigenic (CTX+) V. cholerae Strains 63
4.2.1 O1 Serogroup 63
4.2.1.1 Classical Strains 63
4.2.1.2 El Tor Strains 64
4.2.2 O139 Strains 68
4.2.3 CTX+ Non-O1, Non-O139 Strains 70
4.3 Non-choleragenic Strains 72
4.3.1 Pre-CTX+ O1 and Non-O1, Non-O139 Strains 72
4.3.2 CTX /Pre-CTX O1 Strains 73
4.3.3 CTX /Pre-CTX Non-O1, Non-O139 Strains 76
4.4 Environmental Strains: Harmless Refugees or Ambushing Bandits? 78
4.5 Conclusions 79
References 80
5 The Re-emergence of Cholera in the Americas 89
5.1 Introduction 89
5.2 Epidemiology of Cholera in Americas 90
5.3 The Environmental Aspects of Cholera 93
5.4 Management of Cholera and Other Related Diarrheal Infections 95
5.5 Molecular Characterization of V. cholerae 95
5.6 Vibrio cholerae Non-O1 Associated with Cholera-RelatedDiarrhea 101
References 102
6 The Evolution of Vibrio cholerae as a Pathogen 106
6.1 Introduction 106
6.2 Pathogenesis 107
6.3 Emergence of Endemic and Pandemic Vibrio cholerae 109
6.4 Horizontal Transfer of Vibrio cholerae Virulence Genes 110
6.5 Reactogenicity of Nontoxigenic Vaccine Prototypes in Humans 112
6.6 The Discovery of Zot and Ace 112
6.7 Other Toxins and Virulence Loci in the Evolution of Vibrio cholerae 115
6.8 Conclusion 117
References 118
7 Molecular Epidemiology of Toxigenic Vibrio cholerae 124
7.1 Introduction 124
7.2 Epidemiology of Cholera: Overview 126
7.3 Molecular Epidemiological Tools 126
7.4 Molecular Epidemiology of Cholera 127
7.4.1 Clonal Diversity of Epidemic Strains in Bangladesh and India 128
7.4.2 Changing Antibiotic Resistance Among Toxigenic Vibrio cholerae 130
7.5 Molecular Basis for Clonal Diversity 131
7.6 Influence of Clonal Diversity on the Epidemiology of Cholera 132
References 133
8 Diversity and Genetic Basis of Polysaccharide Biosynthesis in Vibrio cholerae 137
8.1 Introduction 138
8.2 Lipopolysaccharide (LPS) 139
8.2.1 Lipid A 139
8.2.1.1 Composition and Structure of Lipid A 139
8.2.1.2 Genetics of Lipid A Biosynthesis 140
8.2.2 Core Oligosaccharide 140
8.2.2.1 Composition and Structure of Core Oligosaccharide 140
8.2.2.2 Genetics of Core Biosynthesis 140
8.2.3 O-Polysaccharide (O-Antigen) 141
8.2.3.1 Serogroup O1 142
8.2.3.2 Serogroup O139 145
8.2.3.3 Serogroup O22 147
8.2.3.4 Serogroup O37 149
8.2.3.5 Serogroup O31 150
8.3 Horizontal Gene Transfer (HGT) in Creation of O-Antigen Diversity 151
8.3.1 Mechanism of HGT-Evidence for Homologous Recombination Events 154
8.3.2 Vehicles for HGT of O-Antigen/Capsule Regions 154
8.4 Exopolysaccharide (EPS)/Vibrio Polysaccharide (VPS)/Rugose Polysaccharide 155
8.4.1 V. cholerae Generates Colonial Variants Termed Smooth and Rugose 155
8.4.2 The Rugose Variant Has an Increased Capacity to Survive Biocides and Environmental Stresses 156
8.4.3 The Rugose Variant Has Increased Capacity to Form Biofilms 156
8.4.4 EPS/VPS Production 156
8.4.5 VPS Biosynthesis and Analysis of the Functions of the vps Genes 157
8.4.6 VPS Cluster Is Unique to V. cholerae 158
8.4.7 Regulators of VPS Production 158
8.4.8 Type II Secretion System in VPS Export 160
8.5 Concluding Remarks 161
References 162
9 Significance of the SXT/R391 Family of Integrating Conjugative Elements in Vibrio cholerae 169
9.1 Introduction 169
9.2 Discovery of SXTMO10 in a Novel Epidemic-CausingSerogroup of Vibrio cholerae 171
9.3 Apparent Dissemination of SXTMO10-Related ICEs inEpidemic Vibrio cholerae 172
9.4 The Origin of SXTMO10-Related ICEs 177
9.5 SXT/R391 Family Members Possess a Large Core Set of Conserved Genes 178
9.6 SXT/R391 Family Members Also Possess Variable Regions 179
9.7 Conjugative Transfer and Regulation of the ICEs of the SXT/R391 Family 180
9.7.1 Excision and Integration 180
9.7.2 Conjugative Transfer 181
9.7.3 Conjugative Transfer Entry Exclusion 182
9.7.4 Regulation 183
9.8 Do ICEs of the SXT/R391 Family Mobilize Vibrio cholerae Virulence Determinants? 184
9.9 Concluding Remarks 187
References 188
10 Small Molecule Signaling Systemsin Vibrio cholerae 193
10.1 Introduction 194
10.2 Intracellular Small Molecule Signaling Systems 194
10.2.1 Intracellular cAMP-Mediated Regulation in Vibrio cholerae 195
10.2.2 Guanosine 3'-Diphosphate 5'-Triphosphateand Guanosine 3',5'-Bis(diphosphate) [(p)ppGpp]as Cellular Alarmones in Vibrio cholerae 196
10.2.2.1 Role of (p)ppGpp in Vibrio cholerae 197
10.2.3 Bis-(3,5)-cyclic-di-guanosine Monophosphate (c-di-GMP) 198
10.2.3.1 c-di-GMP-Mediated Signaling in Vibrio cholerae 198
10.2.3.2 c-di-GMP and In Vivo Gene Expression in Vibrio cholerae 200
10.3 Extracellular Quorum Sensing in Vibrio cholerae 203
10.3.1 Quorum-Sensing Molecules and Pathways in Vibrio cholerae 203
10.3.2 Quorum Sensing-Regulated Virulence Gene Expression and Biofilm Formation in Vibrio cholerae 204
10.3.3 Relationship Between Quorum Sensing and c-di-GMP in Vibrio cholerae 205
10.4 Concluding Remarks 205
References 206
11 Vibrio cholerae Flagellar Synthesisand Virulence 210
11.1 Introduction 210
11.2 The Vibrio cholerae Flagellar Transcription Hierarchy 211
11.3 Motility and Virulence 214
11.4 Chemotaxis and Virulence 215
11.5 Motility and Biofilm Formation 216
11.6 Summary 216
References 217
12 Filamentous Phages of Vibrio choleraeO1 and O139 220
12.1 Introduction 220
12.2 Isolation of Filamentous Phages from Stool Samples 221
12.3 Typing and Subtyping of Filamentous Phages 221
12.4 Filamentous Phages as a Tool for Molecular Epidemiology of V. cholerae 221
12.5 Receptor for Filamentous Phages fs1 and fs2 222
12.6 Role of Filamentous Phages in Pathogenesis of V. cholerae 222
12.7 Genomic Organization of fs2 223
12.8 att Site-Containing Region of fs2 224
12.9 Strategies for Development of an Effective Cholera Vaccine Phase Variation of V. cholerae 224
12.10 Development of Hyperfimbriate Strains of V. cholerae O1 226
References 227
13 Pathogenic Potential of Non-O1, Non-O139 Vibrio cholerae 229
13.1 Introduction 229
13.2 Ecology and Epidemiology 230
13.3 Strain Diversity 231
13.4 Toxins and Toxigenic Factors 232
13.5 CTX Prophage (Genetic Element) and VPI 234
13.6 Pathogenic Potential 235
13.7 Evolutionary Perspective 237
13.8 Conclusion 240
References 241
14 Proteases Produced by Vibrio choleraeand Other Pathogenic Vibrios:Pathogenic Roles and Expression 250
14.1 Introduction 251
14.2 Vibrio cholerae Protease 251
14.2.1 Hemagglutinin/Protease (HA/P) 251
14.2.2 Quorum-Sensing Regulation of HA/P Production 254
14.2.3 Other Proteases of Vibrio cholerae 256
14.3 Proteases Produced by Other Vibrios 256
14.3.1 Vibrio vulnificus Protease (VVP) 256
14.3.2 Vibrio parahaemolyticus and Others 257
14.4 Conclusions 258
References 259
15 Toxins of Vibrio choleraeand Their Role in Inflammation,Pathogenesis, and Immunomodulation 264
15.1 Introduction 264
15.2 Cholera Enterotoxin 266
15.2.1 Immune Modulation by Cholera Toxin 267
15.2.1.1 B and T Cells 268
15.2.1.2 Monocytes and Macrophages 268
15.2.1.3 Dendritic Cells 268
15.3 The Other Toxins of Vibrio cholerae 269
15.3.1 Zona Occludens Toxin (Zot) 269
15.3.2 Accessory Cholera Enterotoxin (Ace) 269
15.3.3 WO7 Toxin 269
15.3.4 Hemolysin--Cytolysin 270
15.3.5 Non-membrane Damaging Cytotoxin (NMDCY) 271
15.3.6 Shiga-Like Toxin 271
15.3.7 Heat-Stable Enterotoxin (ST) 271
15.3.8 New Cholera Toxin (NCT) 272
15.3.9 Secreted CHO Cell-Elongating Protein (S-CEP) 272
15.3.10 Repeat in Toxin (RTX) 272
15.4 Role of Additional Toxins in Inflammation and Immunomodulation in Cholera Disease 273
References 275
16 Vibrio cholerae Hemolysin: An EnigmaticPore-Forming Toxin 281
16.1 Introduction 281
16.2 Expression, Isolation, and Purification 282
16.3 Structure and Biophysical Characteristics 283
16.4 Receptor Specificity, Membrane Binding, and Bilayer Insertion 287
16.5 Interaction of VCC with Nonerythroid Cells: Relevance to Disease 289
16.6 Conclusion 290
References 290
17 Integron-Mediated AntimicrobialResistance in Vibrio cholerae 294
17.1 Introduction 294
17.2 General Characteristics and Classes of Integrons 295
17.3 Mobile Integrons (MIs) 296
17.4 Superintegrons (SIs) 298
17.5 Epidemiology of Vibrio cholerae with Class 1 Integrons 299
17.5.1 South-east Asia 299
17.5.2 South Asia: India 301
17.5.3 Africa 303
17.5.4 Europe 305
17.5.5 South America 305
17.6 Complex Class 1 and Class 2 Integrons in Vibrio cholerae 305
17.7 Class 1 Integrons in Other Vibrios 306
17.8 Conclusion 307
References 308
18 Aquatic Realm and Cholera 314
18.1 History of Cholera 315
18.1.1 Old Beliefs and Myths About Cholera 315
18.1.2 Historical Background and Global Occurrence of Cholera 315
18.2 Ecology of Vibrio cholerae 317
18.2.1 Environmental Factors Affecting the Organism 317
18.2.2 Biological Factors Affecting the Organism 318
18.2.2.1 Viable but Non-culturable State 318
18.2.2.2 Biofilm Formation 320
18.2.2.3 Rugosity and Colonial Opacity 321
18.2.2.4 Quorum Sensing 322
18.2.2.5 Chitinase and Chitin Utilization 324
18.2.2.6 Intracellular Existence 325
18.3 Detection of Vibrio cholerae from the Environments 325
18.3.1 Conventional Bacteriological Culture Methods 325
18.3.2 Colony Blot Lift and Hybridization with DNA Probes 326
18.3.3 Immunological Methods 327
18.3.4 Direct Detection of Vibrio cholerae by PCR 327
18.4 Prediction and Prevention of Cholera 329
18.4.1 Climatological Models for Prediction 329
18.4.2 Simple Methods for Prevention and Intervention of Cholera 331
18.5 Summary 333
References 334
19 Management of Cholera 343
19.1 Background 343
19.2 Clinical Presentations 345
19.3 Management 346
19.3.1 Management of Patients with 'No' Dehydration 347
19.3.2 Management of Patient with 'Some' Dehydration 347
19.3.3 Oral Rehydration Salt (ORS) Solution 348
19.3.4 Management of Patient with Severe Dehydration 349
19.3.5 Management with Antibiotic 350
19.3.6 Management of Vomiting 350
19.4 Feeding 351
19.5 Other Drugs or Agents 351
19.6 Complications 351
References 352
Subject Index 356