About Harmful Bacteria
Only a small portion of bacteria are disease-causing pathogens. Harmful bacteria can damage tissues, produce toxins, or trigger dangerous inflammation. Public health, sanitation, vaccines for some bacterial diseases, and appropriate medical treatment have greatly reduced many bacterial illnesses.
Pathogens
A pathogen is a microorganism capable of causing disease.
Learn MoreToxins
Some bacteria produce chemicals that damage cells or disrupt body functions.
Learn MoreHow Infections Spread
Disease-causing bacteria can spread through several routes.
Learn MoreImmune Defenses
The immune system recognizes and attacks invading bacteria.
Learn MoreAntibiotics
Antibiotics are medicines that target bacteria, not viruses.
Learn MoreAntibiotic Resistance
Bacteria can evolve resistance to antibiotics.
Learn MoreFood Safety
Some bacteria multiply in food and can cause illness.
Learn MorePublic Health
Clean water, sanitation, surveillance, and vaccination prevent many bacterial diseases.
Learn MorePathogens
Whether illness occurs depends on the species or strain, the number of organisms, where they enter the body, and the health and immune defenses of the host. Many bacteria that normally live harmlessly on the body can cause trouble if they enter the wrong location.
Toxins
Bacterial toxins work in different ways. Some damage cell membranes, some interfere with nerves, and others overstimulate immune responses. Understanding toxins has helped scientists develop treatments and vaccines for certain diseases.
How Infections Spread
Depending on the organism, transmission can involve contaminated food or water, respiratory droplets, direct contact, animals, insects, or contaminated surfaces. Different diseases therefore require different prevention strategies.
Immune Defenses
Skin and mucus provide physical barriers. If bacteria enter tissues, immune cells can engulf them, produce antibodies, and coordinate inflammation. Fever and swelling are signs of immune activity, though severe infections may require medical care.
Antibiotics
Different antibiotic classes interfere with bacterial cell walls, protein production, DNA processes, or other functions. A clinician chooses treatment based on the infection, likely organism, allergies, local resistance patterns, and other medical factors.
Antibiotic Resistance
Random genetic changes or acquired resistance genes can allow some cells to survive a drug. Those survivors reproduce, making resistant strains more common. Using antibiotics only when medically appropriate helps slow this evolutionary process.
Food Safety
Keeping foods at safe temperatures, preventing cross-contamination, cooking foods appropriately, washing produce when recommended, and following public-health guidance reduce risk. Different foods have different safety requirements.
Public Health
Modern sewer systems, safe drinking water, food inspection, infection control, and disease monitoring have saved enormous numbers of lives. Public-health measures often prevent infections before treatment is needed.