CHAPTER ONE
INTRODUCTION AND LITERATURE REVIEW
1.0 Introduction
Water is a natural resource and is essential to sustain life. Accessibility and availability of fresh clean water do not only play a crucial role in economic development and social welfare (Odonkorand Ampofo,2013) but also, it is an indispensable liquid. Many do not have access to safe and clean water and many dies of waterborne bacterial infections. Hence, having it available in sufficient quantity and quality contributes to the maintenance of health (Nougang et al., 2011). According to WHO (2004), about 80% of all diseases and over one-third of deaths in developing countries are caused by drinking contaminated water.
Water is essential to human life, for basic health and survival, as well as food production and economic activities. Presently, the world is facing a global emergency in which over one billion people lack access to a basic supply of clean water and over 2billion do not have access to adequate sanitation which is the primary cause of the waterborne disease (WHO, 2003). Water aids in digestion and is essential in almost all other body processes. It makes up more than two-thirds of human body weight, and without water, there is no life. The human brain is made up of 95% water, blood is 82%, and lungs 90%. Water helps in maintaining the moisture of internal organs of the body, the normal volume and consistency of fluids such as blood and lymph as well as in the regulation of body temperature, removal of poisons or toxins from the body through urine, sweat and breathing; and the regulation of the normal structure and functions of the skin. The body loses about four litres of water every day. It is, therefore, necessary to replenish this volume daily by drinking at least the equivalent amount of quality water. In developing countries with deteriorating environments, the demand for clean drinking water supply is growing rapidly in recent times(Odonkor and Ampofo,2013).
Most of the infections (like cholera, typhoid, hepatitis, poliomyelitis etc.) in developing countries can be attributed to lack of safe drinking water. This owing to the fact that water is obtained from various untreated sources, among which are streams, lakes, rivers, ponds, rain, springs and wells (Okonko et al., 2008). Large percentage of the population in developing countries are not adequately supplied with potable water and is thus compelled to use water from sources like shallow wells, boreholes, springs and streams that render the water unsafe for domestic and drinking purposes due to high possibilities of contamination (Welch et al., 2000; Jamielson et al., 2004; WHO, 2006). Faecal contamination of water is established by the presence of faecal organisms because they do not occur freely in nature. The presence of Escherichia Coli, Clostridiumperfringes and Streptococcusfaecalis in water is sufficient evidence that the water is not safe since enteric pathogens are confirmed present (Ohanu et al., 2012).
Aims and Objectives
The aim of the study is to isolate and identify Escherichia coli as an indicator of faecal pollution in streams on Obafemi Awolowo University (O.A.U) campus, Ile-Ife, Osun state.
Objectives of the study
To isolate and identify Escherichia coli in O.A.U streams, Osun state, Nigeria.
To determine the antimicrobial susceptibility pattern of the strains in the samples analysed.
1.1 Literature Review
1.1.1 Water
Potable water is defined as water that is free from disease-producing microorganisms and chemical substances deleterious to health (Ihekoronye and Ngoddy, 1985). Before water can be described as being potable, it has to comply with certain physical, chemical and microbiological standards designed to ensure that the water is potable and safe for drinking (Tebutt, 1983).
Ensuring standard quality of environmental water used as a source of recreational or drinking water is an important worldwide problem. Meanwhile, the presence of these organisms may cause gastroenteritis in humans (Ratajczak et al., 2010). According to the World Health Organization and European guidelines, Escherichiacoli indicates faecal contamination of water (Ratajczak et al., 2010).
1.1.2 Pollution of Water
Surface water such as rivers, streams can be choked with sediments, hazardous substances or poorly treated effluents accruing from industrial activities, which in turn renders the water bodies unsuitable for use. Polluted surface water can contain a wide variety of pathogenic microorganisms including bacteria and viruses. Unfortunately, clean, pure and safe water can exist only briefly in nature and immediately polluted by prevailing environmental factors aided by human activities. Water from most sources is therefore unfit for immediate consumption without some sort of treatment (Okonko et al., 2008).
During the early history of various countries, epidemics of diseases such as typhoid, shigellosis, cholera and amoebiasis were common threats (Tyagi et al., 2006). It was subsequently discovered that sewage was the primary source. Human faecal pollution enters water bodies in a number of ways- from point sources (discharges from municipal sewage treatment plant and leaking sewage pipes) and non-point sources (such as runoff, landfills, failing septic systems and improper sewage disposal). Wastewater effluents are a major source of faecal contamination of aquatic ecosystems (George et al., 2002).
The presence of poisonous chemical substances, pathogenic organisms (infective and parasitic agents), industrial or other wastes or sewage in water makes it contaminated or polluted. To ensure safe consumption and use, water has to be examined microbiologically to determine its sanitary and its suitability for general use (Ohanu et al., 2012).
1.1.3 Quality of Water
The quality of water influences the health status of any populace, hence, analysis of water for physical, biological and chemical properties including trace element contents are very important for public health studies. Shortage of infrastructure for effective treatment and distribution of water accounts for the incidence of high morbidity and mortality rate associated with water-borne diseases in developing countries. One of the targets of the millennium development goals (MDG) in terms of healthy living for the masses can be achieved through the supply of safe and available water (Orewole et al., 2007). The availability of good quality water sources is, therefore, getting more and more limited, and the effect of water-borne pathogens on human health is expected to be of great concern. It is, therefore, important to understand the significance of natural and drinking water contribution to the transmission of pathogenic microorganisms (Suresh and Smith, 2004).
The quality of water may be described according to its physicochemical and microbiological characteristics (Muniyan and Ambedkar, 2011).
1.1.3.1 Physicochemical parameters
The pH is the measurement of the acid/base activity in solution. In natural waters, the pH scale runs from 0 to 14 and it is the most important parameter in determining the corrosive nature of water. The lower the pH value, the higher the corrosive nature of water (Gupta, 2009). The water temperature plays an important role in the solubility of salts and gases. It is one of the most significant parameters which control inherent physical qualities of water (Hamaidi-Chergui et al., 2013). The TDS are the total concentration of dissolved solids in water, and sometimes also influences the salinity behaviour of river water. It is composed of inorganic salts and some inorganic materials as well as dissolved organic matter. The presence of these minerals in the water would come from a number of natural sources as well as from the result of human activities.
1.1.3.2 Microbiological Quality
The microbiological quality of treated wastewater is a concern to customers, water suppliers, regulators and public health authority alike (Odonkor and Ampofo 2013). The increasing industrialization and the growing water demand has led to a global deterioration of surface water quality (Tyagi et al., 2006). Thus, the need to assess the microbiological safety of these waters by analysing them for the presence of specific pathogens and, directing efforts to the removal of indicator microbes of faecal origin (George et al., 2002; Tyagi et al., 2006).
Maintenance of the microbiological quality and safety of water systems used for drinking, recreation, and in the harvesting of seafood is imperative, as contamination of these systems can exert high risks to human health as well as result in significant economic losses due to closures of beaches and shellfish harvesting areas. Water contaminated with human faeces is generally considered as a greater risk to human health, as they are more likely to contain human-specific enteric pathogens, including Salmonellaenterica serovar Typhi, Shigella spp., hepatitis A virus, and Norwalk-group viruses. Animals can also serve as reservoirs for a variety of enteric pathogens (various serotypes of Salmonella, Escherichia Coli, and Cryptosporidium spp.). Understanding the origin of faecal pollution is paramount in assessing associated health risks as well as the actions necessary to remedy the problem while it still exists (Griffin et al., 2000; Scott et al., 2002).
Monitoring the microbiological quality of drinking water relies largely on the examination of indicator bacteria such as coliforms, Escherichia coli and Pseudomonas aeruginosa (Odonkor and Ampofo, 2013). The presence of Escherichia coli in water is a strong indication of recent sewage contamination. It is important to note that Escherichia coli and wastes can get into the water in many different ways. For example, during rainfall and snowmelt, Escherichia coli may be washed into creeks, rivers, streams, lakes or groundwater (Griffith et al., 2003; Roslev and Bukh, 2011) from a land surface (Rock and Rivera, 2014).