Bactérias potencialmente patogênicas em trecho do Ribeirão Jacutinga - PR, após despejo de esgoto sanitário tratado

Abstract

Microbiological contamination, physical or chemical from effluent into bodies of water can cause serious damage to the ecological balance and mainly to public health. The Ribeirao Jacutinga, classified as Class 2 sweet water, is receiving body of waste, including sewage treatment plant in the city of Ibiporã. The sewage treatment plant mentioned has in its composition than those domestic and industrial wastewater, but also hospital effluent, thus leading to a greater contribution of potentially pathogenic bacteria such as Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Thus, this study aimed to isolate and quantify these potential pathogenic bacteria and analyze their resistance and sensibility to disinfectant and antibiotics. To do the analysis, samples were collected in four points: Output ETE (P1); 11 meters upriver from sewage dump (P2); 7 meters downstream of the dump (P3) and 63 meters downstream of the dump (P4). Measurements of physical-chemical parameters such as turbidity, temperature, dissolved oxygen, pH and conductivity, was performed on river (P2, P3, P4) and for the identification, isolation and quantification of bacteria was used Difco CHOMagar Orientation selective medium, MacConkey agar medium, medium Cetrimide, morphotypes tests and biochemical tests. The assessment of bacteria resistance to antibiotics, susceptibility testing was performed the test - diffusion Kirby-Bauer disk. For the disinfectant it was used the sodium hypochlorite, benzalkonium chloride and hydrogen peroxide/peracetic acid, in which the sensitivity was found for the time 15 ", 30", 60 ", 5 ', 10', 20 'and 30 '. For bacteria tested for erythromycin antibiotic, there was 100% of resistance. And For all disinfectants the minimum time of inactivation was around 10 minutes of contact. Bacteria with greater frequency and abundance were Acinetobacter spp. (1,35x105 CFC.mL-1) and Staphylococcus aureus (6,56x104 UFC.mL-1), both in point 1. Pseudomonas aeruginosa was the bacteria with lower incidence. The bacteria considered within the coliform group had relatively low values when compared with the others. The maximum value of colony forming units of Escherichia coli and Klebsiella pneumoniae was 3,0x103 CFC.mL-1 and 8,0x103 CFC.mL-1. Thus, the use of only coliform bacteria as indicators of water quality is inefficient when it comes to correlate with the presence of potentially pathogenic bacteria.