Bacteria are small single-celled organisms. They are found everywhere on Earth, sometimes in extreme conditions, and many play a critical role in the Earth's ecosystems. The human body is full of bacteria. Most of them are harmless, and some are even helpful. A relatively small number of them cause diseases. They’re on your skin, in your airways and mouth, and also in your digestive system, reproductive system and urinary tract. You may have ten times more bacterial cells than human cells in your body. There are three basic bacterial shapes: Spheres or ball shapes (cocci) Rod-shaped (bacilli) Spirals or helixes (spirochetes) Bacteria and viruses are different kinds of microorganisms. Both may cause infections and result in similar symptoms. However, bacteria are in general larger and more complicated organisms than viruses. A bacterium has a rigid cell wall containing a cell membrane, which holds cytoplasm. In this fluid are chromosomes (made up of DNA) that hold the instructions for making new bacteria and performing other functions. Bacterial infections and viral infections require different methods of treatment. Antibiotics can be used to treat some bacterial infections, but antibiotics won’t work on viruses. This means, for example, that the common cold, which is caused by a virus, can't be treated with antibiotics. Bacteria can be harmful or beneficial. Some, like e coli, can be both. Harmful Bacteria Bacteria that are harmful to humans and cause diseases are called pathogenic. Harmful bacteria examples include: Streptococcus: bacteria that cause strep throat Staphylococcus: bacteria that cause staph infections Escherichia coli: bacteria that cause E. coli infections These bacteria are the most common germs responsible for septicemia, or blood poisoning. This infection occurs when bacteria enter your bloodstream. Bacteria in blood can spread and lead to sepsis, a systemic overreaction to widespread infection in your body. Other examples of pathogenic bacteria include: Aerococcus urinae: bacteria in urine that cause urinary tract infections Chlamydia trachomatis: bacteria causing chlamydia, a sexually transmitted infection Bordetella pertussis: bacteria that cause whooping cough Antibiotics can treat most types of bacterial infections. However, the more you take an antibiotic, the greater the chances your body will become resistant to it. Bacterial resistance is also more likely if you don't finish or take your antibiotics as prescribed. Find out more here. Moreover, When we take antibiotics to treat an infection of harmful bacteria, we also kill helpful bacteria. This can cause an imbalance of bacteria in the body that can lead to diarrhea and other gastrointestinal problems. Helpful Bacteria Good bacteria help our bodies digest food and absorb nutrients, and they produce several vitamins in the intestinal tract, including folic acid, niacin, and vitamins B6 and B12. Beneficial bacteria may also protect against harmful ones that cause disease by producing acids that inhibit their growth, and stimulating the immune system to fight them off. Helpful bacteria examples include: In the gut: Bifidobacteria: lactic acid bacteria that promote vitamin manufacture, digestion help, infection prevention, and immunity Lactobacillus acidophilus: bacteria that aid manufacturing of vitamin K and other infection-fighting agents E. coli: bacteria that help to digest food in the large intestine by releasing enzymes Other places: Streptomyces: bacteria used to manufacture antibiotics, antifungal agents, and other medicines Rhizobium: bacteria in the soil that supply ammonia to plants, which is necessary for their growth Many foods contain friendly bacteria, such as: yogurt buttermilk cheeses with live active cultures sauerkraut beer sourdough bread chocolate kimchi Resources HTML, graphics & design by Bill Willis 2023