Browsing by Author "M Ezzat, Safaa"

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Antibiotics resistance phenomenon and virulence ability in bacteria from water environment
(Taylor & Francis, 2017) I Azzam, Mohamed; M Ezzat, Safaa; A Othman, Badawi
This study aims to determine the impact of five main drains as sources of antibiotics resistant bacteria in River Nile at Rosetta branch, and to generate a baseline data on their virulence ability. Out of 212 bacterial isolates, 39.2% and 60.8% were recovered from drains and Rosetta branch, respectively. Susceptibility of bacteria to different antibiotics showed multiple antibiotics resistances (MAR) for the majority of isolates. Meanwhile, sensitivity was mostly directed to ofloxacin and norfloxacin antibiotics. Calculated MAR index values (>0.25) classified area of study as potentially health risk environment. Testing virulence ability of bacteria from drains showed positive results (65%). Contrastively, virulent strains in Rosetta branch were mostly lacking in this study. Concluding remarks justify the strong correlation (r = +0.82) between MAR and virulence of bacteria in polluted aquatic ecosystems, and highlight the potential of drains as reactors for their amplification and dissemination. The study suggests regular monitoring for antibiotics resistance in native bacteria of River Nile, prohibition of unregulated use of antibiotics, and proper management for wastes disposal.
Applying Quantitative Microbial Risk Assessment Model in Developing Appropriate Standards for Irrigation Water
(Integrated Environmental Assessment and Management, 2019) M Ezzat, Safaa
This study aimed to apply a quantitative microbial risk assessment (QMRA) model to estimate the annual risk probability of Salmonella infection associated with the consumption of crops, which were irrigated with raw wastewater abstracted by farmers without official permission. Data generated from the model were used to propose realistic standards for Salmonella in irrigation water needed for safe crop production. Results demonstrated the presence of total coliforms, fecal coliforms, fecal streptococci, and Salmonella in wastewater samples. Salmonella was recorded on lettuce and spinach in 3 different harvesting events, although it was not found in data obtained for parsley plant. The QMRA scenario included surface irrigation, consumption of raw crops, and 1‐day withholding period before harvest. The annual risk probability of Salmonella infection for consumers exceeded the target tolerable risk (7.7 × 10−4) for investigated crops. The Pearson's correlation coefficient between different annual risk probabilities showed significant correlation (p < 0.05). The levels of risk posed from spinach and lettuce were roughly similar, although they tended to be higher for lettuce. The optimum concentrations of Salmonella in irrigation water needed to satisfy the World Health Organization guidelines of disease burden (disability‐adjusted life years 10−6) per person per year ranged from 34 to 119 via multiple‐tube fermentation technique/100 mL, for spinach and lettuce plants, respectively. The study concluded that unofficial reuse of wastewater in irrigation is a principle route for crop contamination. Water quality monitoring programs should be integrated with QMRA investigations for better estimation of risk level. The fit parameters used could be tailored to cover a wide array of local situations in different countries. Models applied for viruses, helminths, and bacteria other than Salmonella are encouraged in future studies
Wastewater as a Non-conventional Resource: Impact of Trace Metals and Bacteria on Soil, Plants, and Human Health
(Taylor & Francis, 2019) M Ezzat, Safaa; M Elkorashey, Reham
In many arid and semi-arid regions, farmers are often obligated to informally use raw wastewater for irrigating their crops. The impacts of wastewater irrigation on soil, crops, and human health were investigated, regarding trace metals and bacteria. Cr, Cu, Fe, Ni, and Zn were detected in wastewater. Cr, Cu, and Zn accumulated in soil and crops in the order rocket > clover > cabbage. The Health Risk Index reported risk from Cr and Zn in rocket. Fecal coliforms in wastewater and crops were detected along with Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The frequency (%) was 86.7% (cabbage), 66.7% (rocket), and 43.3% (clover). The multiple antibiotic resistance index (0.503) rendered crops high risk source for contamination. The comprehensive pollution index classified wastewater severely polluted (≥2.01). Conclusions deduced crops alternative reservoirs for trace metals and human pathogens. Recommendations included implementation of low cost treatment methods, holding irrigation 5–15 days before harvest, assuming citric and acetic acids reducing solutions for trace metals, and suggested ofloxacin, amoxycillin/clavulanate, and amikacin antibiotics against reported bacteria