Helpful and Harmful Types of Bacteria

Bacteria are an important group of living organisms. Most of them are microscopic and unicellular, with a relatively simple cell structure, lacking a cell nucleus, and organelles such as mitochondria and chloroplasts. A tough protective layer called a cell wall encloses almost all kinds of bacteria. The cell wall gives the bacterium its distinctive shape and enables it to live in a wide range of environments. A capsule, a slimy layer outside the cell wall, further encloses certain species. The capsule causes the cell to be resistant to destructive chemicals. All bacteria possess a cell membrane, an elastic, bag-like structure immediately inside the cell wall. Small molecules of food enter the cell through pores in this membrane, but large molecules cannot pass through it. Inside the membrane is the cytoplasm, a jellylike, soft substance. The cytoplasm contains chemicals called enzymes, which help build cell parts and break down food.

Bacteria can be categorized as living cells unlike viruses. Bacteria are found everywhere from the tallest mountains to the deepest parts of an ocean on earth. The air is replete with bacteria. Certain bacteria spend their whole lives in the atmosphere, reproducing and growing in the clouds. Although bacteria lack distinct nuclear structures common to the cells of higher organisms like animals and plants and are able to reproduce successfully and transfer genetic information from one generation to the next. Motile bacteria can move about, either using bacterial gliding, flagella or changes of buoyancy.

Almost 99% bacteria are helpful. Disease is caused by only a few of them. Water, food, and air carry bacteria from one person to another. Bacteria can be classified into three types on the basis of shape. The sphere shaped bacteria, rod shaped bacteria and spiral bacteria are the three types.

Helpful bacteria

• Certain types of bacteria live in the intestines of human beings. They help in digestion and in destroying the harmful organisms. Intestinal bacteria also produce some vitamins required by the human body.
• Certain bacteria help break down lactose in the digestive tract.
• It is observed that Infants who were administered the bacteria Lactobacillus reuteri or Bifidobacterium had fewer and shorter episodes of diarrhea.
• Fermented milk containing the live bacteria Lactobacillus casei helps in eradicating harmful bacteria Helicobacter pylori in children.
• Saccharomyces boulardii is found to reduce the risk of antibiotic-associated diarrhea in children.
• Some bacteria present on the skin protect us from the spread of certain fungus.
• It was found that DNA damage was significantly reduced by all six strains of lactic acid producing helpful bacteria tested with the exception of Streptococcus thermophilus.
• There are many types of bacteria that live inside the mouth, nose, throat, and intestines of humans and animals. These bacteria get a place to live and feed while keeping other harmful microbes from taking up residence.
• Certain stomach bacteria may work harmoniously with our immune system. There are billions of stomach bacteria, which are friendly or beneficial bacteria.
• There are some friendly bacteria such as intestinal flora or micro flora which are good for human health. These healthy stomach bacteria are helpful to release many useful vitamins such as vitamin B and vitamin K, etc. The most important task that stomach bacteria do is to maintain normal pH level or acid level of human stomach.

Harmful bacteria

• Certain bacteria act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, food-borne illness and tuberculosis.
• Streptococcus bacteria may cause small infections like strep throat and some serious diseases like pneumonia. Certain streptococci may be fatal.
• Bacteria that usually live harmlessly in the body may cause infections when a person's resistance to disease is reduced in conditions such as AIDS (Acquired Immune Deficiency Syndrome).
• Not all stomach bacteria are beneficial, some of the stomach bacteria enter the body through the mouth, and they can survive in the acidic conditions in the stomach and can cause serious diseases and can be fatal.
• Campylobacter is a group of bacteria that can create illnesses in humans and is a common cause of food poisoning.Harmful bacteria in food cause botulism, which can cause paralysis or even death if even one millionth of the bacterium is ingested.
• Yersinia pestis or bubonic plague, is a rod-shaped type of bacterium which is well known for its harmful nature. Bacteria-carrying fleas found on animals such as rats and mice transmit the bacteria that are believed to have caused the deaths of millions of people in human history.

Antibiotics are widely used to kill harmful bacteria. Washing hands with antiseptic soap will kill the bacteria. Don’t eat or drink from unhygienic places. One should realize that while good bacteria can survive without us, we cannot survive without good bacteria.