Study finds caffeine can weaken effectiveness of certain antibiotics University of Tübingen researchers discover substances bacteria can find in their natural environment trigger their alert system – could have implications for future therapeutic approaches Ingredients of our daily diet – including caffeine – can influence the resistance of bacteria to antibiotics. This has been shown in a new study by a team of researchers at the Universities of Tübingen and Würzburg led by Professor Ana Rita Brochado. They discovered bacteria such as Escherichia coli (E. coli) orchestrate complex regulatory cascades to react to chemical stimuli from their direct environment which can influence the effectiveness of antimicrobial drugs.