ResultsThe percentages of pathogenic bacteria isolated from different water sources in (Table 1) clarified that the percentage of E.coli isolates were significantly higher in both tap and hand pump water trough (31/57; 54.38% and 11 /26; 42.31%, respectively) at X2= 12.32 (P<0.05). Meanwhile, both K. Pneumonae, and S. aureus were isolated in the highest percentage in hand pump water (9/26; 34.61% and 6/26; 23.07%, respectively) compared to tap water (16/57; 28.07% and 10/57; 17.54%, respectively). On the other hand, the main sources were free from bacterial contaminants especially the hand pump supply.Concerning, the biocidal efficacy of Ca(OCl)2 disinfectant against isolated bacterial pathogens in water sources (Table 2). It has been showed that the efficacy of Ca(OCl)2 disinfectant against K. Pneumonae and E. coli was greatly obvious at a concentration of 0.02 mg/L after 180 mins of exposure time (80 and 70 %, respectively) while its efficacy against S. aureus was 50% at the same concentration and exposure time as compared to the lower concentration and other exposure times. Meanwhile, the biocidal effect of Ca(OCl)2 disinfectant on pathogenic bacteria after 120 mins of exposure time was weak whereas the isolated bacteria exhibited their resistance profile (E.coli ,K. pneumonae and S. aureus; 50, 40 and 60%, respectively) compared with those exposed to lower concentration of 0.01 mg/l (70,40 and70%, respectively).On the other hand, the sensitivity of pathogenic bacteria isolated from different water supplies to AgNPs in (Table 3) exhibited the biocidal effect of AgNPs against bacterial isolates, K. pneumonae followed by E.coli and S. aureus (100, 90 and 80%, respectively), at a concentration of 100 mg/l after 60 mins of exposure time compared to 30 mins of exposure time (90, 80 and 70, respectively). Meanwhile, all isolated bacteria showed a highly resistant pattern to other concentration of AgNPs (50 mg/l) at different exposure times (10, 15, 30, 60 mins, respectively). The efficacy of AgNPs/ Ca(OCl)2 disinfectant against all bacterial isolates in (Table 4). It has been revealed that the bacterial isolates from different water sources were highly sensitive (100%) to AgNPs/ Ca(OCl)2 disinfectant at a concentration of 0.002 mg/L after 60 mins exposure time. Meanwhile, its efficacy after 30 mins of exposure was 90 and 80 % each for S. aureus, K.Pneumonae and E.coli, respectively compared with those exposed to lower doses (a concentration of 0.001 mg/l) at different exposure times.Biocidal efficacy of AgNPs/ Ca(OCl)2 filter paper was against indicator bacteria in different water sources after 10 mins of exposure (Table 5). It has been found that prior treatment with biocidal filter paper, the TVCs, TCC, and FCC in tap water source were the highest (4.52 x105, 46.0 and 14.0 CFU/100 ml, respectively) and exceeded the WHO limit of (1.0×102 CFU/ ml of TVC and 0.0 CFU/ml for TCC), compared to hand pump water of small cattle breeders (2.23x103, 18 and 4.0 CFU/100 ml, respectively). Meanwhile, using of treated filter paper impregnated in AgNPs/ Ca(OCl)2 disinfectant exhibited a high reduction in counts of indicator bacteria closed to the maximum permissible limit. Moreover, the entire water samples required 0.002 mg/L of AgNPs/Ca(OCl)2 disinfectant for complete destruction of pathogenic bacteria in examined water samples in addition to effluent water (drain water) compared with those exposed to lower dose (a concentration of 0.001 mg/l induced 2.1x102 and 1.1x102 CFU/ml). Discussion Microbial monitoring of water quality at small cattle breeders is an essential element for controlling the antimicrobial resistant bacteria and to reduce the risk exposure to each human being and farm animals as consumers, especially in developing countries. In this study, the relationship between the presence of waterborne pathogenic bacteria in water troughs and its sensitivity to calcium hypochlorite disinfectant, AgNPs and AgNPs/Ca(OCl)2 are studied. It has been found that drinking water troughs were highly contaminated with E.coli bacteria at small cattle breeders that used tap water as the main source. Meanwhile, hand pump (ground) water troughs had the highest percentage of isolated bacteria such as K. Pneumonae and S. aureus which attributed to the absence of hygienic measures that should be applied for protecting the drinking water from contaminants. Furthermore, retention of water in troughs for long time and absence of sanitizers used for cleaning of water troughs. These findings are in harmony with Aragan (2012) clarified the important role of drinking water for dairy cattle in transmission of pathogenic bacteria that caused in the occurrence of some diseases such as enteritis, mastitis, and calf diarrhea. E. coli is the most reliable indicator bacteria of water fecal contaminant and give the indication on a hygienic status of freshwater sources (Johannessen et al. 2002), where the detection process of this bacteria is easy to perform (Health Canada, 2012; Odonkor and Ampofo, 2013). On the other hand, Huisamen (2012) recorded that industrial effluent is discarded into nearby surface and ground water resources that exposed water to contamination and subsequently increase the risk to food safety. The biocidal activity of calcium hypochlorite against bacterial strains isolated from different water supplies in the present study showed the sensitivity of K. Pneumonae and E. coli didn't exceed eighty percent at the highest concentration dose after 180 minutes of exposure time. Furthermore, its efficacy against S. aureus strains was fifty percent. These results exhibited the sensitivity of bacterial strains was variable in the same stains in addition to between other isolated strains from different water sources and its influence by a concentration dose and exposure times on their sensitivities. Wojcicka et al. (2007) revealed that exposure of microorganisms to repetitive disinfection events exhibit the difference in inactivation kinetics between species and/or variability occur between the same species of bacterial strains in addition to their ability to develop resistance within its cell structure. Other studies reported that the main components of bacterial outer membrane including proteins, fatty acid and phospholipids could be reduced the disinfection performance (Winder et al. 2000; Méchin et al. 1999; Boeris et al. 2007). While, Li et al. (2013) found that treatment of water with sodium hypochlorite at a concentration of 10 mg/l and 0.2-0.3 mg/l after thirty minutes of exposure time was effective in reduction of coliform bacteria (3.8 and 3.5 logs, respectively). With regards, the biocidal efficacy of silver nanoparticles (AgNPs) exceeded eighty percent against both E.coli and S. aureus while it reached to lethal effect one hundred percent against K. pneumonae at the highest concentration dose (100 mg/L) after 60 minutes of exposure time compared to other concentration doses and exposure times. Lok et al. (2007), Han et al. (2005) and Yang et al. (2007) found that the concentration of AgNPs used for inactivation of bacteria in water was ranged from 5.4-108ppm. Furthermore, the minimal inhibitory concentration values were dependent upon diameter of NP, a concentration of bacteria and exposure times. From this point, the present study aimed to improve Ca(OCl)2 disinfectant performance used for drinking water treatment throughout loaded it on nanoparticles (AgNPs) and using lower doses with decrease contact times to reach to the best results. It has been revealed that the lethal effect of nanocomposite (AgNPs/Ca(OCl)2) was significantly high (100%) against bacterial isolates from different water sources at a concentration of 0.002mg/l after sixty minutes of exposure time. This effect might be attributed to the ability of silver ions to binding and penetrate the cell membrane of bacteria and increasing the permeability of it. These findings are in accordance with Morones et al. (2005) and Sondi and Salopek-Sondi (2004) who revealed that using of AgNPs in the treatment of water led to increasing cell membrane permeability and leakage of the cytoplasm of E.coli bacteria. Furthermore, the antibacterial effect of AgNPs has been attributed to release of Ag ions from the silver nanoparticle surface and binding on thiol groups in membrane protein and subsequently cause DNA aggregation (Lok et al.2007; Feng et al.2000). While in this study, using of calcium hypochlorite loaded on silver nanoparticles and tested their efficacy against bacterial isolates is considered the first record to the best of our knowledge whereas the lethal effect was very obvious against pathogenic bacteria with the shortage of contact time. Moreover, Implementation of field trial using of biocidal filter paper impregnated in AgNPs/ Ca(OCl)2 disinfectant against indicator bacteria and total viable bacterial counts exhibited a high reduction in counts of indicator bacteria that closed to the maximum permissible limit. Dankovich and Gray (2011) clarified that the detection of indicator bacteria are more practical and easier to enumerate than detection of pathogenic waterborne bacteria in addition to its usefulness in prediction the risk of exposure to pathogenic bacteria. Moreover, total coliform, fecal coliform, E.coli, fecal streptococci, and enterococci are the most frequently examined coliform bacteria and also they found that the synthesized filter paper (AgNP paper) was strongly effective for the inactivation of pathogenic E.coli and Enterococcus faecalis.