The influence of selected antibiotics on aquatic microorganisms.

This paper presents the influence of penicillin, erythromycin, oxytetracycline and streptomycin on aquatic microorganisms isolated from three reservoirs with varied extent of environmental pollution (Sulej6w Reservoir, Zegrze Reservoir and Vistula River). The experiments were conducted in especially prepared microcosms (aerated 151 aquariums). From among the examined antibiotics streptomycin showed the longest activity in the water environment (27 days), followed by oxytetracycline (22 days). Erythromycin had 13 days activity while the penicillin only 4 days. The highest number of bacteria was observed in the Vistula, fewer in Zegrze Reservoir. Sulejów Reservoir was characterized by the lowest number of bacteria. The strains isolated from Sulej6w Reservoir were characterized by higher degree of biodiversity than those from Zegrze Reservoir or Vistula River. The dominant genera were Pseudomonas (49%), followed by Acinetobacter (21%), Flavomonas (9%), Alcaligenes (9%), Vibrio, Moraxella and Oligella. The Vistula River was dominated by Aeromonas (88%) and Pseudomonas (12%) genera. The strains isolated from Sulej6w Reservoir were more sensitive to antibiotics than those from the much more polluted Vistula, this being evidenced by lower MIC and MBC values.