RESISTANCE AGAINST β-LACTAM ANTIBIOTICS: A GLOBAL PERSPECTIVE IN A CONNECTED WORLD

The use of antibiotics has grown dramatically over the past seven decades, and today these compounds are extensively used in human and veterinary medicine. However this has resulted in increased antibiotic resistance (AR), which is expected to reach “pandemic-like” levels in the coming years. Although many efforts are being made to avoid the above described scenario, there is still a lack of understanding regarding AR dynamics, especially outside of clinical settings. Several recent studies have demonstrated a close relationship between AR mechanisms in clinical settings and natural environments. However, modes of action responsible for mobilizing AR elements across natural and clinical environments are still not well understood. In the present work, we focused on resistance to β-lactam antibiotics, the most used antibiotic class in human and animal medicine. Initially, we applied in-silico comparison of β-lactamase genes in hundreds of metagenomes from different environments. Subsequently, we analyzed samples from within and downstream from wastewater treatment plants (WWTPs), using a novel Illumina-based amplicon sequencing pipeline that enabled characterization of hundreds of thousands of integron-associated genes per sample. Our preliminary results show substantial differences in the abundance and type of β-lactamase genes across the different environments. The analysis of AR genes in class 1 integrons indicates dynamic changes across the different steps of WWTPs, but very little transfer of WWTP effluent-associated class 1 integron genes in downstream soils. On the whole, our results help in the global understand of the AR phenomenon across different environments, and even more, we can connect AR phenomenon with mobile genetic elements such class 1 integrons in an effort to understand potential risks of AR dissemination in the environment.