[Fecal Streptococci in the waters of the Zaiman stream]. / Investigación de estreptococos fecales en aguas del arroyo Zaimán.

The investigation was focused on the occurrence of different species and biovarieties of fecal streptococci in Zaiman creek waters, the basin of which comprises important zones of Posadas, Misiones. The samples were collected from points near a meat-packing industrial establishment which pours its effluents in the above mentioned water course. So far, 18 sampling operations have been carried out in representative geographic locations. The methodology followed for detecting and characterizing the present species consisted in an enrichment procedure performed by incubating samples in Azida Dextrose broth at 35 degrees C during 24-48 h. Further streaks were made on KF Agar and Kanamycin Agar plates. The biochemical study of the colonies developed in Brain Heart Agar media was the one described in the American Water Standards (APHA and EPA). The isolation frequency of the different species of fecal streptococci is shown. (Table 2). The efficiency of both culture media KF Agar and Kanamycin Aesculin Azide Agar proved to be similar. (Table 1). The distribution of fecal streptococci by sampling points shows that the pollution comes not only from the pourings of effluents but also from the population settlement near the water course.