Antibiotics Evolve Bacteria in the Gut

New antibiotics have been coming out at frequent intervals since then, and bacteria have evolved resistance to just about every one of them. Nowadays, the most ominous example is MRSA (methycillin-resistant Staphylococcus aureus), which has succeeded in making many hospitals positively dangerous places to visit. Another menace is ' C. diff.' ( Clostridium difficile). Here again, we have natural selection favouring strains that are resistant to antibiotics; but the effect is overlain by anothe...