CHAPTER ONE
Water is a simple molecule, consisting of two hydrogen atoms bonded to an oxygen atom with molecular formula H2O (Bassem, 2013). It is one of the most important chemical substances for the sustenance of life and is vital for all known forms of life on Earth; It constitutes about 75% of the Earth`s surface (UN, 2005; EL-Jakee et al., 2009; Hongyue et al., 2013). In terms of sheer volume, About 97.5% of all the water on Earth is salt water, only 2.5% of all the water on Earth is fresh water and 98.8% of that fresh water is frozen in Antarctica and Greenland icecaps or lies too deep underground to be accessible; only 1.2% of the Earth’s freshwater is available for withdrawal and human use (Shiklomanov, 2000; UN, 2005; Bassem, 2013). However, this is continually being polluted by various anthropogenic activities thereby further reducing the available freshwater for human use. The drinking water of most communities including Zaria in Nigeria is obtained from various sources: boreholes, rivers, streams, and well waters. Source water contamination poses a risk to public health and increases the cost of drinking water treatment.
The threats posed by deteriorating water quality caused by among other things, the contamination of potable water sources have led the public to seek for alternative potable water sources. Although access to safe and reliable sources of drinking water is a global challenge, it is particularly acute in developing countries, including Nigeria (Ivey et al., 2006).
The production, sale and consumption of plastic bagged drinking water has grown tremendously over the years in many developing countries such as Nigeria. The plastic bagged drinking water was introduced into the Nigerian market as a less expensive means of accessing drinking water than bottled water.
1.1 Statement of Research Problem
Estimate of the global burden of water associated human diseases provide a simple index hiding a complex reality. World Health Organization (WHO) estimates that worldwide some 2.2 million people die each year from diarrhoeal related diseases. For an estimated 88% of diarrhoeal cause, the underlying cause is unsafe water, inadequate sanitation and poor hygiene (WHO, 2008; Mosier et al., 2012). Water borne diseases continue to be one of the major health problems in developing nations, including Nigeria especially on the issues of safe drinking water quality (Mead et al., 1999). Water borne diseases account for one third of the intestinal infection worldwide (Hunter and Syed, 2001; Offre et al., 2011).
The high prevalence of diseases such as diarrhoea, typhoid fever, cholera, and bacillary dysentery among the populace have been linked to the consumption of unsafe water and unhygienic drinking water production practices (Mead et al., 1999; Park et al., 2010). Pathogens such as Salmonella species, Shigella species, Vibrio cholerae and E. coli being seen in human and animal faeces ultimately find their way into water supply through seepage of improperly treated sewage into ground water, (Dipaola, 1998; Wei et al., 2011).
1.2 Justification for the Study
Most bottle water manufacturers in Nigeria also engage in sachet water packaging and obtain their raw water mostly from local, municipal piped or well water, however, adherence to production and analytical standards are doubtful as most of the factories are observed to lack the appropriate technology for achieving these (Oyedeji et al., 2013). Diseases related to contamination of drinking-water constitute a major burden on human health and interventions to improve the quality of drinking-water provide significant benefits to health (UNDP, 2006). The potential health consequences of microbial contaminations are such that its control must always be of paramount importance and must never be compromised (Mead et al., 1999).
1.3 Research Hypothesis
HO: Packaged and other drinking water sources in Zaria do not meet the bacteriological quality standard.
HO: Drinking water sources do not contain Escherichia coli O157:H7.
HO: The target pathogenic bacteria are not resistant to the antibiotics tested.
HO: Escherichia coli O157:H7 and Enterococcus spp isolated do not possess the virulence shigatoxin genes (Stx1 and Stx2) and antibiotics resistance genes (CTX-M, TEM) and vanr.
1.4 Aim
The aim of this study was to carry out bacteriological and physicochemical quality assessment of packaged and other drinking water sources in Zaria, Kaduna State, Nigeria.
1.5 Objectives were to:
1. Determine the bacteriological quality and physicochemical properties of packaged and other drinking water sources.
2. Isolate and characterize Escherichia coli O157:H7 and Enterococcus spp in the water samples
3. Determine the antibiotic susceptibility patterns of the isolates to commonly used antibiotics and screen for the presence of multiple antibiotic resistance strains.
4. Screen the Escherichia coli O157:H7 for the possession of extended spectrum βlactamases genes (bla-CTX-M and bla-TEM) and virulence shigatoxin genes (Stx1 and Stx2) using the polymerase chain Reaction (PCR) technique.
5. Confirm Enterococcus using genus specific primer and detect the Vancomycin resistance gene (VANR) in Enterococcus spp. isolated.
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