Microbiota de um rio urbanizado: caracterização, diversidade e perfil de susceptibilidade

Abstract

Highly polluted waters have a high concentration of fungal and bacterial communities. The lack of protection from springs, deforestation, silting up of rivers and anthropic activities along the riverside are examples of the possible causes of contamination. The indiscriminate use of antifungals is an emerging concern, since these drugs do not require a medical prescription, resulting in uncontrolled trade by the regulatory agency. These drugs are widely used in medical, agricultural and veterinary activities. As a result, antibiotics and microorganisms end up being directed mainly at water bodies. The objective of this research was: to evaluate the water quality along the Toledo River by means of microbiological and physical-chemical analyses; to analyze physical-chemical data of environmental quality, to quantify bioindicator microorganisms of water quality, to characterize isolated yeasts; to observe the diversity of species by means of molecular analyses; to evaluate how resistant these yeasts are to the antifungal drugs fluconazole and itraconazole, and to analyze anthropic interference in the rural and urbanized stretch of the Toledo River. The analysis of Biochemical Oxygen Demand, heterotrophic microorganisms, total coliforms and total yeasts obtained a statistically significant difference between the rural and urbanized stretch of the river, considering p <0.05. In the MIC test for fluconazole, there was susceptibility of 29% of the tested yeasts, 22% of dose-dependence and resistance in 49%. For itraconazole there was susceptibility of 2%, dose-dependence of 10% and resistance in 88% of the tested yeasts. So far, 12 strains have been identified, Candida palmioleophila and 1 strain of Torulaspora pretoriensis. It is confirmed that anthropic activities such as ruralization and urbanization compromise the quality of this water body and human health since the Toledo River is classified as a class II river, being allowed leisure activities, fishing, agricultural irrigation and public supply.