Helpful and Harmful Bacteria

Good and bad germs in our world...

What is bacteria?

Bacteria are microscopic organisms that are all around us. They are in the air, on our skin, in our bodies, in the ground, and all throughout nature. Bacteria are single- celled organisms and are unique because they lack a nucleus, the part of a cell that helps control eating, reproduction, and movement. Bacteria come in all sorts of shapes including rods, spirals, and spheres. Some “swim” around using long tails called flagella. The others (without flagella) just hang out or glide along.

Helpful Bacteria

Even though some bacteria can make us sick, most are not dangerous. For many years bacteria have been used by us to create food products like cheese, yoghurt, pickles, soy sauce and vinegar. Many bacteria reproduce quickly. Some can double their amount in as little as twenty minutes!

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1) Lactobacillus

There are more than 80 species of the rod-shaped Lactobacillus! One of these species, Lactobacillus acidophilus, is found in the acidic environment of the intestines where it divides as colonies or chains. This bacteria helps you digest food. As part of the digestion process, L. acidophilus attaches to the lining of the intestines to make lactic acid and hydrogen peroxide from sugars which create conditions that stop the growth of other harmful bacteria.

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2) Staphylococcus epidermidis

Scientists estimate there are over a trillion bacteria living on our skin, most of which are harmless. One of these is Staphylococcus epidermidis. These spherical-shaped bacteria are non-motile. They divide and grow as colonies, or clusters, that can survive with or without oxygen. Their cell wall is made up of "peptidoglycan" which protects the cell from overexpansion (and cell death) in the presence of water. Staphylococcus epidermidis help us by: 1) killing pathogenic bacteria that may cause infection, 2) stimulating our body to make antibodies (which boost our immune system), and 3) making and secreting vitamins and nutrients that our body needs.
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3) Escherichia Coli

Escherichia Coli are rod-shaped bacteria that can be a helpful and harmful. They are asexual and divide by making an exact copy of themselves. They possess flagella that help them to move. Their capsule produces a "slime" that helps them to attach to surfaces and survive in harsh conditions such as the gut where they help with food digestion and produce vitamin K which allows us to form blood clots, build strong bones and prevent heart disease.
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4) Rhizobia

Rhizobia are motile, rod-shaped bacteria that divide as colonies or chains of cells. They require oxygen to survive and their cell wall is made up of sugars that allow them to interact, or form nodules, with the roots of plants like beans and peas. The bacteria produces nitrogen compounds that help the plant to grow. Rhizobia supply the plant with nitrogen and in turn the plant supplies the bacteria with essential minerals and sugars.
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5) Bacillus brevis

Bacillus brevis are rod-shaped and use their flagella to move. This bacteria forms "endospores" which are structures that allow the bacteria to survive in harsh conditions common to soil and decaying matter. Their cell wall secretes and antibiotic called gramicidin which is used in topical ointments to prevent infections such as acne.

Harmful Bacteria

Only a handful of bacteria are capable of causing disease. These are called pathogens. Pathogens can cause food poisoning, leprosy, pneumonia, tetanus and more. Fortunately, we have antibiotics. We can take antibiotics to kill the pathogens. Other ways to fight of pathogens include washing your hands, keeping wounds clean, and preventing physical contact with someone who is sick.

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1) E. Coli

Again, E. coli can be helpful and harmful. Certain types (called strains) of E. coli can get into your blood. Although this condition is rare, it can cause a very serious infection. Some symptoms include nausea, stomach cramps and vomiting.
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2) Staphylococcus aureus

Like the S. epidermidis species, Staphylococcus aureus are spherical and non-motile; however, this bacteria has long been known as one of the most important bacteria that causes disease in humans. It is the leading cause of skin and soft tissue infections. Although most staph infections are not serious, S. aureus can cause serious infections such as bloodstream infections, pneumonia, or bone and joint infections
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3) Streptococcus pneumoniae

Streptococcus pneumonia are round to oval shaped, divide to produce exact copies (asexual) and are transmitted from person to person through the air, even though they can grow without oxygen. They live in the respiratory tract of humans but, in the right conditions, can cause serious bacterial infections like pneumonia, middle ear infections and meningitis which is an infection around the brain and spinal cord. S. pneumonia have a capsule and cell wall that contain choline which allows them to stick to the human cells and invade the bloodstream. Pneumococcal infections are the most common invasive bacterial infections in children in the United States.
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4) Clostridium Difficile

Clostridium difficile are motile, rod-shaped bacteria that reproduce by binary fission to create two identical daughter cells. They can live with or without oxygen. When overgrown, C. difficile release toxins that attack the lining of the intestines, causing a condition called Clostridium difficilecolitis. This condition can range from mild to life-threatening. Some of the symptoms include severe abdominal pain, fever, loss of appetite, blood in the stool and weight-loss.
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5) Helicobacter Pylori

Helicobacter Pylori (H. Pylori) is one of the most successful pathogens known to humans. It is an "S-shaped" rod bacteria with many flagella that allow it to twist and turn. It causes chronic inflammation and infection by penetrating through the cells lining the intestines; then the bacteria secretes ammonia which is toxic to human cells. Although many infected individuals have no symptoms, others may experience bloating, belching, nausea, vomiting and abdominal discomfort. More serious symptoms include abdominal pain, fatigue, low red blood cell counts, bad breath and heart burn.