[Antibiotic and metal resistance in "Escherichia coli" strains isolated from the environment and from patients (author's transl)].

The incidence and the patterns of the antibiotic and metal resistance in 106 strains of Escherichia coli isolated from ground waters, used also as drinking water supply (sample A), was studied in comparison with the resistance behaviour in the 104 strains of the same microorganism isolated from non hospitalized patients (sample P). Significant differences between the percentage of resistant strains in the two examined samples were found for some of the antibiotics and the metals tested (ampicillin, streptomycin, kanamycin, mercury and zinc) while non statistically significant differences were found for gentamicin, tetracyclin, nalidixic acid and cadmium. From the high percentages of the resistant strains in the environmental sample (up to 44.3% for tetracyclin) we may deduce that also the ground waters, especially if used as drinking water, contribute to the spread of the resistant bacteria. The patterns of the antibiotic multiresistances in the strains isolated from patients and from ground waters do not differ greatly and this strengthens the hypothesis that resistance to antibiotics has been acquired by Escherichia coli strains before reaching the ground waters.