Most drinking water in Algerian dry regions comes from groundwater. The quality and purity of this groundwater has direct effect on human health. The use of certain bacteria, as indicators of the potential presence of pathogenic microorganisms in natural and treated waters, is the standard means of assessing the microbiological quality of a water body (Nair et al., 2006). Water scarcity is a major problem in many developing countries. Drinking water is indispensable for human life. However, in many parts of the world, the water is provided only at certain time intervals during the day. Although connected to a supply system, the user still has to store water to have a sufficient amount of water available during the non-supply periods. People can survive days, weeks or months without food, but only about four days without water. The body uses water for digestion, absorption, circulation, transporting nutrients, building tissues, carrying away waste and monitoring body temperature.

Water can be hard or soft, natural or modified, bottled or tap, carbonated or still (Kendall, 1992). The human bacterial pathogens that can be transmitted by consuming contaminated drinking water, and that present a serious risk of disease, include Salmonella spp. Shigella spp. enterovirulent Escherichia coli, Vibrio cholera, Yersinia enterocolitica, Campylobacter jejuni and Campylobacter coli. After being excreted in faeces from the body of their host, bacterial pathogens gradually lose viability and the ability to cause infection. The rate of decay varies with different bacteria; it is usually exponential, and after a certain period a pathogen will become undetectable. The most common waterborne pathogens are those that are highly infectious or highly resistant to decay outside the body. Pathogens with a low persistence, which do not survive long outside the host, must rapidly find a new host and are more likely to be spread by person-to-person contact or by poor personal or food hygiene than by drinking water (Mc Michael, 2000). Algeria is largest country in Africa and lies mostly in the arid region where water is a scarce commodity, it is considered to be rich in water resources (Kihal et al., 2002). The disease causing organisms called pathogens are discharged along with faecal wastes and are difficult to detect in water supplies. Fortunately, less harmful, easily isolated bacteria called indicator organisms can be used indirectly to detect pathogens. Among these indicators are coliforms bacteria. They live in the intestine of man and other animals and are almost always present, even in healthy people. The presence of coliforms in water is a warning signal that more dangerous bacteria may be present. Diseases resulting from ingestion of pathogens in contaminated water have the greatest public health impact worldwide. Presence of faecal coliforms or E. coli is used as an indicator for the presence of any of the waterborne pathogens (Naresh et al., 2013). The common feature of all routine screening procedures is the primary examination for indicator microorganisms rather than the pathogens. Indicator microorganisms are bacteria such as non-specific coliforms, E. coli and Pseudomonas aeruginosa that are very commonly found in the human or animal gut and which, if detected, may suggest the presence of sewage (Zamberlan et al., 2008; Odonkor and Ampofo, 2013). Indicator organisms are used because even when a person is infected with more pathogenic bacteria, they will still be excreting many millions times more indicator organisms than pathogens. It is therefore reasonable to deduce that if indicator organism levels will be very much lower or absent. World Health Organization (WHO, 1993) recommends that no faecal coliforms will be present in 100 ml of drinking water. Good quality water is odorless, colorless, tasteless and free of faecal contamination and chemicals in harmful amounts. Potable or drinking water can be defined as the  water  delivered  to  the that can be safety used for drinking, cooking and washing (De Zuane, 1997; Ghorbani et al., 2013). The main objective of present study was to identify environmental factors determining total and fecal coliforms and other indicators bacteria levels in drinking water. It was hoped that information from this study might help facilitate source water protection and establish more effective water treatment strategies in Algeria dry zones.

All the water samples were analysed in Béni-Abbès hospital laboratory. A number of 300 samples were examined in the study. All samples were tested for bacteriological contamination by total aerobic bacteria, indicators groups and potential pathogenic bacteria (Table 1).

Bacteriological analysis of water

Total plate count

Total plate count for total bacterial count performed for all water samples showed only 58.33% samples were within the WHO (1996) guideline value (<10 cfu/ml). In source wise distribution of samples, 20% of spring water Sidi Othman, 70% of well municipal, 60% of Ougarta's foggara, 40% of Béni-Abbès foggara, 50% of Zeghamra's drilling and 10% of Béni-Abbès drilling samples has exceeded the guideline value.

Coliform count

Source wise distribution of coliform count showed that the 30% of spring water Sidi Othman, 50% of well municipal, 50% of Ougarta's foggara, 40% of Béni-Abbès foggara, 40% of Zeghamra's drilling and 20% of Béni-Abbès drilling crossed WHO guideline value (0 cfu/100 ml).

Fecal streptococci count

Source wise distribution of faecal streptococci count showed that the 20% of spring water Sidi Othman, 60% of well municipal, 50% of Ougarta's foggara, 40% of Béni-Abbès foggara, 50% of Zeghamra's drilling and 10% of Béni-Abbès drilling.

Isolation and identification of bacteria

In this study, 274 isolates of enteric bacteria obtained were identified as E. coli (22.98%), Enterobacter spp (11.06%), Citrobacter spp (6.81%), Pseudomonas aeruginosa (8.09%), Salmonella typhi (18.72%), Salmonella para typhi A (5.53%), Serratia spp (9.36%), Vibrio cholerae (0%) from Vibrio (0.85%) and 16.6% Clostridium (Madigan et al., 1997; Dhanya et al., 2013). Results of the bacteriological analysis of the water sample are presented in Table 3.

The total viable counts for all water samples were quite high ranging from 135 × 10³ cfu/ml to 25 × 10³ cfu/ml. The Ougarta's foggara sample has the highest microbial load of 135 × 10³ while well water far away from refuse site had the least value of 25 × 10³cfu/ml (Table 2). The most probable number (MPN) for presumptive total coliform count of the water samples ranged from 1, 6 to140 MPN per 100 ml. Water samples well municipal and Ougarta's foggara (Table 3). Vibrio cholerae count of all water samples not detected but in the well municipal there is a suspected result (Table 3). Salmonella count is detected for samples well municipal and Ougarta's foggara (Table 3). The bacteria isolated from water samples in this work included E. coli, Enterobacter gergoviae, P. aeruginosa, S. typhi, S. para typhi A, Vibrio vulnificus and Clostridium spp. (Table 3). Heterotrophic count measures a range of bacteria that are naturally present in the environment (EPA, 2002). The total bacterial counts for all the water samples were generally high exceeding the limit of 1.0 × 10² cfu/ml which is the standard limit of heterotrophic count for drinking water (EPA, 2002).

The high total heterotrophic count is indicative of the presence of high organic and dissolved salts in the water. The primary sources of these bacteria in water are animal and human wastes. These sources of bacterial contamination include surface runoff, pasture, and other land areas where animal wastes are deposited. Additional sources include seepage or discharge from septic tanks, sewage treatment facilities and natural soil plant bacteria (EPA, 2002). These contaminants are reflected in the highest bacterial load obtained in this study for the Ougarta's foggara water samples.

The microbial count was higher in well municipal water close to refuse disposal site as compared to well water far away but both microbial counts are  lower than that of spring water Sidi Othman. Generally, underground water is believed to be the purest known (Gordan and Gever, 1996; Prescott et al., 2002; Ayoade et al., 2013) because of the purification properties of the soil; however, it can also be contaminated. Ground waters are found to be contaminated due to improper construction, shallowness, animal wastes, proximity to toilet facilities, sewage, refuse dump sites, and various human activities around the well (Bitton, 1994)..The presumed reason for contamination of well water accounts for why the microbial load of well municipal water close to refuse disposal site have higher microbial count than the one far away from refuse disposal site. Environmental Protection Agency (EPA) establishes heterotrophic plate count as a primary standard, which is based on health considerations.

Accordingly, the total coliform count for all samples was exceedingly high the EPA maximum contamination level for coliform bacteria in drinking water of zero total coliform per 100 ml of water (EPA, 2003). The high coliform count obtained in the samples may be an indication that the water sources are faecally contaminated (EPA, 2003; Osuinde and Enuezie, 1999). None of the water samples complies with EPA standard for coliform in water. According to EPA standard, every water sample that has coliform must be analyzed for either fecal coliforms or E. coli (EPA, 2003; Rizvi et al., 2013).

Other bacteria isolated from all water samples such as P. aeuruginosa (Shittu et al., 2008). Enterobacter aerognes isolated from the water samples are examples of non-fecal coliforms and can be found in vegetation and soil which serves as sources by which the pathogens enters the water (Schlegel, 2002). The British Standard Institute (BSI, 1993) specified that counts greater than 10⁴ are considered unsatisfactory for Enterobacter spp described by Shittu et al. (2008); Manjula et al. (2011).

The main objective of this study was evaluation of quality of drinking water from different sources of Béni-Abbès town. The coliform count has been used extensively as a basis for regulating the microbial quality of drinking-water. In this study, both regulatory parameters were excessively as the WHO guideline values. Study results clearly indicated that most of the natural water sources are less contaminated. The detection of pathogenic enteric bacteria in different sources of drinking water in Béni-Abbès water also reveals the alarming situation for water borne epidemics in water.

Kehr and Butterfield (1943) showed the coliform test to be a useful indicator of S. enterica serovar Typhi. The authors concluded that the presence of even moderate numbers of coliforms presented a high risk, citing an outbreak in Detroit, Michigan, where mean coliform counts in the water supply of only 3 and 10 colony forming units in every 100 ml of water on two successive days were the indicator for an outbreak of waterborne typhoid. Kehr and Butterfield (1943) also noted the much greater risk of gastroenteritis associated with this low coliform count: for the eight cases of typhoid recorded in this outbreak, there were 45 000 cases of gastroenteritis.

Water supply of only 3 and 10 colony forming units in every 100 ml of water on two successive days was the indicator for an outbreak of waterborne typhoid. Kehr and Butterfield (1943) also noted the much greater risk of gastroenteritis associated with this low coliform count: for the eight cases of typhoid recorded in this outbreak, there were 45 000 cases of gastroenteritis.

Water quality indicates that pollution of the water is increasing alarmingly and that it has created serious threat to human health and environment. Bacteriological pollution   of  water  supplies  may  be  either  due  to  the failure of the disinfections of the raw water at the treatment plant or to the infiltration of contaminated water (sewage) through cross connection and leakage points. The results emphasize the importance of adopting appropriate routinely monitoring system in order to prevent or to diminish the chances of contamination of this water source.

The authors have not declared any conflict of interest.