Interactive effects of antibiotics and temperature on freshwater bacteria

Freshwater bodies, such as streams, face contamination from human-made pollutants like pharmaceuticals and are increasingly affected by climate change-induced temperature fluctuations. These stressors often interact in ways that amplify or diminish their individual ecological impacts. Temperature changes acutely affect multicellular organisms, driving species extinction and range shifts, but also profoundly shape microbial communities, despite their adaptability. For instance, bacteria evolved to tolerate higher temperatures can exhibit heightened sensitivity to antibiotics in polluted waters. This is alarming, as bacterial communities are critical to maintaining freshwater quality. Fundamental questions remain about the combined effects of antibiotics and temperature on freshwater microbial communities. In our prior research, we found temperature increases enhanced the efficacy of antibiotics (ciprofloxacin and ofloxacin). Additionally, temperature-dependent synergistic effects of antibiotic mixtures further inhibited bacterial growth, particularly in bacteria already stressed by extreme temperatures. To generalize these findings, we propose experiments to assess the effects of antibiotic cocktails under diverse temperature scenarios across various freshwater bacterial species. This research aims to model and predict how antibiotic mixtures and temperature jointly influence bacterial communities, ensuring more accurate predictions of ecosystem responses to these stressors.