This paper presents the qualitative and quantitative results of the research into potential pathogens of genus Staphylococcus in the air in the centre and in the recreational areas of Olsztyn. The qualitative examinations were conducted for one year, from October 2002 to September 2003, with one-month intervals between measurements, which were done at testing sites with the use of sedimentation and impaction methods of sampling. When the samples were taken by the sedimentation method, the average count of this type of bacteria at various sites was higher than in those taken by the impaction method. The colonies of Staphylococcus bacteria, isolated from air samples taken four times during the test period in October 2002, January, April and July 2003, were further identified down to the species, based on biochemical tests. A wider species diversity of this type of bacteria was found in the samples taken by the sedimentation method (8 species) than by the impaction method (3 species). Among the Staphylococcus bacteria isolated from air the following species dominated: S. xylosus 61% and S. len/us 15% when the samples were taken by the sedimentation method and 31 % and 62%, respectively, with the impaction method. When the samples were taken by the sedimentation method, 8% of Staphylococcus aureus and 2% Staphylococcus epidermidis were found among all the isolated bacteria (627 cfu/m3). These species were not found in the samples taken by the impaction method.

The research covered the determination: of the numbers or hcicrorrophic bacteria: psychrophil ic, psychrctolcrant, mcsophilic and percentage participation or hemolytic bacteria and .ieromonas hydrophila (with acrolysinc and hcmolysine genes) in the waters of the Drwęca River depending on environmental Ilictors and fishery management. The mean quantities 01· hclcrotrophic bacteria (Ht'C) at 4, 14 and 2~°C ranged: O. 78-7.57-101, 1.40-6.65-101 and 1.93-16.23- 103 efuen -3, respectively. The percentage participation 01· hemolytic heterotrophic bacteria (HemPC) and A. hvdrophila among psychrophilic, psychrotolcrant, mcsophilic microorganisms determined at 4, 14, 28°C, ranged: 7.9-10.4, 6.8-12.2, 8.6-22.0 ,111d 1.1-6.4%, respectively. Statistically significant correlation between examined bacteria and temperature values, flows and O2 saturations confirm that the occurrence of those microorganisms depends on the degree of microbiological contamination of that ecosystem, resulting from the fishery management and environmental factors.