Bacterial pathogens recovered from vegetables irrigated by wastewater in Morocco.

* In Morocco, the rate of precipitation has been very low during these last decades.

* Wastewater is increasingly being used in agriculture.

* Wastewater can contain heavy metals, organic compounds, and a wide spectrum of enteric pathogens.

* The use of raw sewage to irrigate crops helps to propagate conditions conducive to cholera and typhoid fever.

* The authors examined 50 vegetable samples from various regions in Morocco.

* The vegetables were tomato, radish, cucumber, eggplant, potato, pepper, garden pea, gourd, zucchini, artichoke, broad bean, turnip, onion, French bean, and lettuce.

* The analyses showed high aerobic-plate, total-coliform, fecal-coliform, and enterococci counts.

* Coagulase-positive Staphylococcus aureus was not detected in any samples.

* Citrobacter freundii and Enterobacter cloacae were recovered most frequently.

* Other Gram-negative bacteria that were frequently isolated were

-- Escherichia coli,

-- Enterobacter sakazakii,

-- Klebsiella pneumoniae, and

-- Serratia liquefaciens.

* The fact that some bacteria and not others are present can be explained by a difference in their capacity to attach to plants.

* Thus, the study demonstrated that the potential for disease transmission exists when wastewater is used for irrigation.

* Pathogens that have been transported by wastewater can survive in soil or on crops.

* In other studies, pathogens have been found not only on outer surfaces, but also in the inner tissues of vegetables grown from experimentally contaminated seeds.

* Similarly, enteric pathogens were isolated from inside vegetables during the authors' investigation.

* A generalized program of wastewater treatment should be considered in Morocco.

* Requirements for treated wastewater should respect sanitary standards for agricultural reuse.

* Also, standard methods of eliminating pathogenic microorganisms from raw vegetables are urgently needed.