The invention relates to a hybrid proteinaceous molecule comprising at least two proteins capable of inhibiting the activity of at least one antibiotic, the proteins each having different biochemical properties and being bonded to one another. The hybrid proteinaceous molecule inhibits the activity of a least one antibiotic in order to reduce the intestinal side effects of antibiotics, such as severe diarrhoea caused by the antibiotics, and nosocomial infections secondary to parenteral antibiotic therapy.
