Antibiotics, resistance and symptom medicines
Infection and response • Communicable diseases
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Key concepts
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Definition and action of antibiotics
Antibiotics comprise medicines that kill bacteria or prevent their growth by targeting bacterial cell walls, metabolic pathways or protein synthesis. Penicillin-type antibiotics weaken bacterial cell walls, causing bacterial cells to burst under osmotic pressure and die. The discovery of penicillin marks the start of modern antibiotic therapy and many related antibiotics follow the same principle, saving many lives by removing bacterial pathogens from inside the body .
Antibiotics are ineffective against viruses
Viruses replicate inside host cells and lack the structures and metabolic processes that antibiotics target. Antibiotics therefore do not kill viral pathogens and do not stop viral replication. Misuse of antibiotics for viral infections provides no benefit to the patient and raises the risk of encouraging bacterial resistance in other bacteria present .
Matching specific antibiotics to specific bacteria
Different bacterial species possess different structures and biochemical pathways. Some antibiotics work only against certain groups of bacteria (narrow-spectrum), while others affect many types (broad-spectrum). Appropriate selection of an antibiotic increases treatment effectiveness and reduces unnecessary exposure of non-target bacteria to the drug. Treatment choice may depend on the identified bacterial species and known antibiotic sensitivities, because some strains already carry resistance to particular antibiotics .
Emergence and concern of antibiotic-resistant strains
Random genetic mutation or acquisition of resistance genes via plasmids produces bacteria that survive an antibiotic dose. Surviving resistant bacteria reproduce and spread the resistance trait, causing antibiotic treatment to become less effective or fail. The rise of strains such as MRSA demonstrates the public-health danger when common antibiotics no longer control infections. Overuse and misuse of antibiotics in medicine and agriculture accelerate the selection and spread of resistance; completing prescribed courses and tighter prescribing slow this process .
Painkillers and medicines that treat symptoms
Painkillers, antipyretics and anti-inflammatory drugs relieve symptoms such as pain, fever and inflammation without killing pathogens. Symptom-relief medicines improve comfort and may prevent dangerous complications (for example, lowering high fever) but do not remove the infective agent. Supportive treatments and symptom control therefore complement, but do not replace, pathogen-targeting therapies when those are required .
Key notes
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