Enumeration of Naturally Occurring Enteroviruses in the Water Samples

Get Complete Project Material File(s) Now! »

HE MICROBIOLOGICAL QUALITY OF WATER

Water supplies in developing countries are devoid of treatment and the communities have to make use of the most convenient supply (Sobsey, 2002; Moyo et al., 2004). Many of these water supplies are unprotected and susceptible to external contamination from surface runoff, windblown debris, human and animal faecal pollution and unsanitary collection methods (Chidavaenzi et al., 1998; WHO, 2000; Moyo et al., 2004). Detection of each pathogenic microorganism in water is technically difficult, time consuming and expensive and therefore not used for routine water testing procedures (Grabow, 1996). Instead, indicator organisms are routinely used to assess the Chapter 2 9 microbiological quality of water and provide an easy, rapid and reliable indication of the microbiological quality of water supplies (Grabow, 1996).

Heterotrophic plate counts

Heterotrophic microorganisms or heterotrophs are naturally present in the environment and can be found in soil, sediment, food, water and in human and animal faeces (Collin et al., 1988; Olson et al., 1991; Standard Methods, 1995; Lillis and Bissonnette, 2001). Broadly defined, heterotrophs include bacteria, yeasts and molds that require organic carbon for growth (WHO, 2002c). Although generally considered harmless, some heterotrophic microorganisms are opportunistic pathogens, which have virulence factors that could affect the health of consumers with suppressed immune systems (Lye and Dufour, 1991; Bartram et al., 2003). Heterotrophic microorganisms can also survive in biofilms inside water distribution systems, water reservoirs and inside household storage containers (Momba and Kaleni, 2002; Jagals et al., 2003). Therefore, heterotrophic plate counts can also be used to measure the re-growth of organisms that may or may not be a health risk (WHO, 2002c). Heterotrophic Plate Count, also known as Total or Standard Plate Count includes simple culture based tests intended to recover a wide range of heterotrophic microorganisms from water environments (Bartram et al., 2003).

otal coliform bacteria

Total coliform bacteria are defined as aerobic or facultative anaerobic, Gram negative, non-spore forming, rod shaped bacteria, which ferments lactose and produce gas at 35°C (Standard Methods, 1995). Total coliforms include bacteria of known faecal origin such as E.

Faecal coliform bacteria

Faecal coliform bacteria are Gram negative bacteria, also known as thermotolerant coliforms or presumptive E. coli (Standard Methods, 1995). The faecal coliform group includes other organisms, such as Klebsiella spp, Enterobacter spp and Citrobacter spp, which are not exclusively of faecal origin (Standard Methods, 1995). Escherichia coli are specifically of faecal origin from birds, humans and other warm blooded animals (WHO, 1996a; Maier et al., 2000). Faecal coliform bacteria are therefore considered to be a more specific indicator of the presence of faeces (Maier et al., 2000). The recommended test for the enumeration of faecal coliforms is membrane filtration using mFC agar and incubation at 44.5°C for 24 h to produce blue colored colonies (Standard Methods, 1995). Faecal coliforms are generally used to indicate unacceptable microbial water quality and could be used as an indicator in the place of E. coli (SABS, 2001).

Escherichia coli bacteria

Globally E. coli is used as the preferred indicator of faecal pollution (Edberg et al., 2000). It is a Gram negative bacterium and predominantly an inhabitant of the intestines of warm blooded animals and humans, which is used to indicate recent faecal pollution of water samples (Rice et al., 1990; Rice et al., 1991; WHO, 1996a; Edberg et al., 2000). Confirmation tests for E. coli include testing for the presence of the enzyme β-glucuronidase, Gram staining, absence of urease activity, production of acid and gas from lactose and indole production (Mac Faddin, 1980; Rice et al., 1991; Standard Methods, 1995). Commercially available growth media containing the fluorogenic substrate 4-methylumbelliferyl-β-D-glucuronidase (MUG) is used for the isolation and identification of E. coli from water samples (Shadix and Rice, 1991; Covert et al., 1992). The E. coli bacteria hydrolyse the MUG in the media, which then fluoresces under ultraviolet light (Shadix and Rice, 1991; Covert et al., 1992).

Faecal enterococci bacteria

Faecal enterococci bacteria are found in the genus Enterococcus and include species like Enterococcus faecalis, Enterococcus faecium, Enterococcus durans and Enterococcus hirae (Standard Methods, 1995; WHO, 1996a). The genus Enterococcus are differentiated from the genus Streptococcus by their ability to grow in 6.5% sodium chloride, pH 9.6, temperatures of 45ºC and their tolerance for adverse growth conditions (Maier et al., 2000). Faecal enterococci are spherical, Gram positive bacteria, which are highly specific for human and animal faecal pollution (Standard Methods, 1995).

TABLE OF CONTENTS :

• DEDICATION
• ACKNOWLEDGEMENTS
• SUMMARY
• OPSOMMING
• LIST OF ABBREVIATIONS
• LIST OF FIGURES
• LIST OF TABLES
• LIST OF PUBLICATIONS AND CONFERENCE CONTRIBUTIONS
• CHAPTER 1: INTRODUCTION
• CHAPTER 2: LITERATURE REVIEW
  • 2.1 INTRODUCTION
  • 2.2 WATERBORNE DISEASES
  • 2.3 THE MICROBIOLOGICAL QUALITY OF WATER
  • 2.4 HUMAN AND ANIMAL FAECAL POLLUTION OF WATER
  • 2.4.1 The Use of Microorganisms to Determine the Origin of Faecal Pollution
  • 2.4.2 The Use of Chemicals to Determine the Origin of Faecal Pollution
  • 2.5 SOURCE WATER SUPPLIES
  • 2.5.1 Water collection from the Source Water Supply
  • 2.5.2 Interventions to Improve Source Water Supplies
  • 2.6 POINT-OF-USE WATER SUPPLIES IN THE HOUSEHOLD
  • 2.6.2 Sustainability of point-of-use interventions
  • 2.7 SUMMARY
• CHAPTER 3: MATERIALS AND METHODS
  • 3.1 INFORMED AND ETHICAL CONSENT
  • 3.2 SCHEMATIC OUTLINE OF STUDY DESIGN
  • 3.3 OBJECTIVE ONE: TO ASSESS AN INTERVENTION STRATEGY TO IMPROVE THE DRINKING WATER QUALITY IN RURAL HOUSEHOLDS
  • 3.3.1 Study Site and Household Selection
  • 3.3.2 Assessment of the Effectiveness, Compliance and Sustainability of a Household Intervention using an Improved Storage Container and a Sodium Hypochlorite Solution
  • 3.3.3 Statistical Analyses of Intervention Study Data
  • 3.4 OBJECTIVE TWO: TO DISTINGUISH BETWEEN FAECAL POLLUTION OF ANIMAL OR HUMAN ORIGIN USING MOLECULAR TYPING OF MALE SPECIFIC F-RNA BACTERIOPHAGE SUBGROUPS
  • 3.5 OBJECTIVE THREE: TO DETERMINE THE SURVIVAL OF INDICATOR MICROORGANISMS AND WATERBORNE PATHOGENS IN THE IMPROVED CDC SAFE STORAGE CONTAINER
  • 3.5.1 Water Samples
  • 3.5.2 Laboratory Based Survival Study Outline
  • 3.5.3 Physico-chemical Analyses of Water Samples
  • 3.5.4 Enumeration of Naturally Occurring Indicator Bacteria and Bacteriophages in the Water Samples (Container 1)
  • 3.5.5 Enumeration of Naturally Occurring Enteroviruses in the Water Samples (Container 1)
  • 3.5.6 Enumeration of Selected Seeded Pathogenic Bacteria and Bacteriophages in the Water Samples (Container 2 or 3)
  • 3.5.7 Enumeration of Seeded Enteroviruses in the Water Samples (Container 3)
  • 3.5.8 Statistical Analysis of the Laboratory Based Survival Study
• CHAPTER 4: RESULTS AND DISCUSSION
  • 4.1 AN INTERVENTION STRATEGY TO IMPROVE THE DRINKING WATER QUALITY IN RURAL HOUSEHOLDS
  • 4.2 DETERMINATION OF FAECAL SOURCE ORIGIN IN STORED DRINKING WATER FROM RURAL HOUSEHOLDS IN SOUTH AFRICA USING MALE SPECIFIC F-RNA BACTERIO PHAGE SUBGROUP TYPING
  • 4.2.1 Prevalence of Male Specific F-RNA Bacteriophages in the Primary Water Sources and the Household Water Storage Containers in Rural Households
  • 4.2.2 Origin of Male Specific F-RNA Bacteriophage Subgroups in the Primary Water Sources
  • 4.2.3 Origin of Male Specific F-RNA Bacteriophage Subgroups in the Stored Household Water at the Point-of-use in the Traditional and CDC Safe Water Storage Containers in Rural Households
  • 4.2.4 Summary of the use of Male Specific F-RNA Bacteriophage Subgroup Typing to Determine the Faecal Source Origin in Primary Water Sources and Drinking Water Stored in Traditional and CDC Safe Storage Containers in Rural Households
  • 4.3 SURVIVAL OF INDICATOR AND PATHOGENIC MICROORGANISMS IN DRINKING WATER STORED IN AN IMPROVED HOUSEHOLD STORAGE CONTAINER WITH OR WITHOUT THE ADDITION OF A SODIUM HYPOCHLORITE SOLUTION
  • 4.3.1 Physical Quality of Improved and Unimproved Water Sources inside the CDC Safe Storage Container over a Period of 5 Days
  • 4.3.2 Free Chlorine Residuals in the Improved CDC Safe Storage Containers after addition of 1% or 3.5% Sodium Hypochlorite Solutions
  • 4.3.3 Survival of Naturally Occurring Indicator and Pathogenic Microorganisms in the CDC Safe Storage Containers Before and After the Addition of a Sodium Hypochlorite Solution
  • 4.3.4 Survival of Seeded Indicator and Pathogenic Microorganisms in the CDC Safe Storage Containers Before and After the Addition of a Sodium Hypochlorite Solution
  • 4.3.5 Summary of the Survival of Selected Indicator and Pathogenic Microorganisms in Drinking Water Stored in an Improved Household Storage Container with or without the addition of a Sodium Hypochlorite Solution
• CHAPTER 5: GENERAL CONCLUSIONS AND RECOMMENDATIONS
  • 5.1 INTRODUCTION
  • 5.2 AN INTERVENTION STRATEGY TO IMPROVE THE DRINKING WATER QUALITY IN RURAL HOUSEHOLDS
  • 5.3 TO DISTINGUISH BETWEEN FAECAL POLLUTION OF ANIMAL OR HUMAN ORIGIN USING MOLECULAR TYPING OF MALE SPECIFIC F-RNA BACTERIOPHAGE SUBGROUPS
  • 5.4 TO DETERMINE THE SURVIVAL OF INDICATOR AND PATHOGENIC WATERBORNE PATHOGENS IN THE IMPROVED CDC SAFE STORAGE CONTAINER
  • 5.5 FUTURE RESEARCH NEEDS
• CHAPTER 6: REFERENCES
  • APPENDIX A: Household Consent Form
  • APPENDIX B: Pamphlets Distributed by the Department of Health and the Department of Water Affairs on the Use of Jik in South Africa
  • APPENDIX C: Questionnaire

GET THE COMPLETE PROJECT
WATER STORAGE IN RURAL HOUSEHOLDS: INTERVENTION STRATEGIES TO PREVENT WATERBORNE DISEASES