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Abstract
The current study was carried out to investigate the public health implications associated with different irrigation waters. For this purpose, twenty water samples (5groundwater, 11surface water and 4wastewater) were collected from irrigation streams in different localities in Egypt. In addition, 162 tomatoes, 89 animals and 60 farm workers samples from fresh produce farms were enrolled in the current study. Isolation of escherichia coli and pseudomonas aeruginosa from water samples was performed using membrane filtration technique then plating was done on selective media, while tomato and animal samples were enriched in tryptic soya broth before streaked on such selective media. Isolates were identified through colonial characters; Gram’s stain and biochemical reactions. Multiplex PCR was performed to identify different E.coli genotypes while conventional PCR was performed to detect exotoxin A gene (toxA) from P. aeruginosa. The results revealed that the microbial quality of irrigation water was varied according to its source, being groundwater usually of good microbial quality whereas wastewater is the poorest one. Highest prevalence of E.coli and P. aeruginosa was recorded in tomatoes irrigated with surface water, in contrast E. coli was not found in tomatoes irrigated with groundwater. Verotoxigenic E. coli (VTEC) was the most frequently genotype recovered from E. coli isolates (74.3%). Vt2 gene was the predominate gene among VTEC tomato isolates. P. aeruginosa isolates were positive to exotoxin A gene (toxA) with percentage (57.3%). Sequencing and phylogenetic tree of 3 P. aeruginosa sequences proved that the water and tomato sequences were more identical to each other recording (98%) than cattle sequence. In conclusion, the current study underscored the potential role of irrigation water in the transmission of water-borne pathogens to both man and animals through direct/or indirect ways via contamination of fresh produce a matter which carries a great public health implication