engleski

Ecotoxicological evaluation and macrolide- resistance diversity of Croatian pharmaceutical effluents

Backgrounds Effluents from antibiotic manufacturing are recognised as the most important contributors to aquatic pollution with antibiotics which could have negative impact on biological balance of natural environments and could also facilitate the development and dissemination of antibiotic resistance. Objectives The objective of this study was to characterize effluents from a local pharmaceutical industry manufacturing the macrolide antibiotic azithromycin with respect to its antibiotic content, ecotoxicity and diversity of macrolide-resistance genes. Methods The effluents were collected on two occasions in 2016, in winter and in spring. LC- MS analysis of effluents showed high concentrations of azithromycin, N-desmethyl azithromycin and dehydrated erythromycin (in the range of mg/L). Ecotoxicity tests showed high toxicity of effluents to diverse freshwater organisms (algae, Daphnia and zebrafish embryos). Culturing showed that effluents contained high frequency of azithromycin-resistant bacteria (> 70%). Functional metagenomics identified two main macrolide resistance mechanisms which include antibiotic efflux and inactivation. Some macrolide resistance genes are flanked by mobile genetic elements such as IS elements suggesting that they are candidates for dissemination to other bacteria in the environment, including pathogens. Conclusions Using a wide array of analyses we have demonstrated that discharges of local pharmaceutical industry may pose a significant ecological and public health concern due to their high toxicity to aquatic biota and the potential to promote global spread of antibiotic resistance.

Macrolide resistance genes ; Pharmaceutical Effluents ; Ecotoxicity ; Antibiotics

nije evidentirano