engleski

Impact of effluents from pharmaceutical industries on natural bacterial communities

Antibiotic manufacturing facilities often produce wastewaters containing high concentrations of antibiotics and other hazardous pollutants. Direct discharge of these wastewaters has been shown to promote the development and spread of antibiotic resistance genes among bacteria, including pathogens. Besides risks for promoting resistance, antibiotic pollution may induce changes in environmental bacterial community composition and functions ; however, such impacts were rarely studied. The objective of this study was to assess the impact of effluents from two Croatian pharmaceutical industries, one synthetizing macrolide antibiotic azithromycin, and the other formulating different veterinary antibiotics, on the natural bacterial communities in the receiving river and stream sediments during two seasons. Results of 16S rRNA amplicon sequencing analyses showed a clearly distinction of bacterial community composition between sediments from the discharge and the other, upstream and downstream sites for both study areas. Bacterial communities from sediments at discharge sites were similar to those in effluents, indicating that bacteria from effluents are deposited in the sediments. However, the majority of these introduced effluent bacteria might not be very well adapted to sediment, allowing the resilence of the indigenous sediment bacterial community as showed by the high degree of similarity among the communities from downstream and reference upstream sediments. Overall, our results showed that industrial effluents influenced the bacterial composition of freshwater sediments close to the effluent discharge.

antibiotic resistance ; pharmaceutical effluents ; freshwater sediments ; bacterial community composition

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