Qualitative bacteriological analysis was carried out in two sewage treatment plants in the city of Rio de Janeiro during the period 1984-1985. Specific points of the plants were selected for the collection of affluent and effluent samples. The study involved the isolation and the identification of 540 cultures of Escherichia coli that were analyzed for their resistance to eight antibiotics (sulfadiazine, streptomycin, tetracycline, chloramphenicol, kanamycin, ampicillin, nalidixic acid and gentamycin), and three heavy metals (copper sulphate, mercuric chloride and zinc sulphate) as well as colicinogeny. About 95% of the isolated cultures from the effluents had genetic markers while the samples originated from the affluents showed 70%.
sewage treatment; Escherichia coli; antibiotic and heavy metal resistances; colicins