engleski

Antibiotic Manufacturing Sites - Hotspots for the Development and Dissemination of Antibiotic Resistance

The highest concentrations of antibiotics in the environment are the result of direct discharges from manufacturing sites. Major discharges, in the mg/L range, clearly selective for antibiotic resistance, have been mostly reported in Asian countries. Consequently, environments exposed to such pollution are considered as ˝hotspots˝ for proliferation of existing and evolution of new antibiotic resistance determinants which we may face in pathogens in the clinic tomorrow. Thus, identification of such ˝hotspots˝ and understanding the dynamics of antibiotic resistance gene (ARG) propagation in them is critical for proper risk assessment and future mitigation efforts. In my lecture, I will present data obtained from two study areas impacted by wastewaters from Croatian pharmaceutical industries that are involved in synthesis and formulation of antibiotics. We have explored the extent of pollution by antibiotics using liquid chromatography/tandem mass spectrometry and the resistome of exposed microbial communities by functional metagenomics, quantitative PCR and exogenous plasmid isolations. We show that exposure to high environmental levels of macrolides are associated with high abundances of mainly known resistance genes to macrolide antibiotics. Integrons and plasmids involved in mobilizing these genes are also highly abundant in these environments. Exposure to lower environmental levels of different veterinary antibiotics resulted, however, in selection of both novel and known ARGs, which were also found in high abundance at wastewater-impacted sites. Overall, our findings show that aquatic environments exposed to industrial discharges are an important reservoirs for maintenance and propagation of ARGs with apparent risk for their transfer to human pathogens. Actions are therefore urgently needed to reduce risks at such locations.

Antibiotic resistance ; Pharmaceutical effluents ; Antibiotic manufacturing ; Sediments

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