Antibiotic resistance occurs when bacteria evolve ways to survive drugs that once killed them, turning routine infections into harder to treat diseases. It arises naturally through random mutations and the exchange of resistance genes between bacteria, but is accelerated by heavy and often inappropriate use of antibiotics in people, animals and agriculture.

Mechanisms of resistance include enzymes that break down antibiotics, pumps that expel drugs from the cell, and changes in bacterial targets so the drug can no longer bind effectively. These adaptations can accumulate, creating multidrug resistant strains such as MRSA and drug resistant tuberculosis.

The spread of resistance is driven by misuse, including taking antibiotics for viral infections, not completing prescribed courses, self medication, and over the counter access without proper diagnosis in some regions. In farming, using antibiotics for growth promotion or routine disease prevention exerts additional selective pressure. Poor infection control, lack of clean water and crowded healthcare settings further facilitate transmission.

Research is focused on new antibiotics, but also on alternative strategies. These include bacteriophages that specifically infect bacteria, molecules that block resistance mechanisms, and treatments that disarm bacterial virulence rather than kill cells outright. Improved diagnostics aim to identify bacterial species and resistance profiles quickly so that therapy can be targeted and unnecessary prescriptions avoided.

Surveillance networks track resistant strains regionally and globally, guiding public health responses. Combating resistance requires coordinated action: better stewardship of existing drugs, vaccination to reduce infections, improved hygiene, and investment in novel therapies to preserve the effectiveness of antibiotics for the future.