Useful Role of Bacteria in Medicine: What comes to mind when you hear the word “bacteria.” Disease! Dirt! Unhygienic! In reality, bacteria don’t make us sick most of the time, but they keep us healthy. Many friendly bacteria reside inside the human body. Although most bacteria are beneficial to us and sustainable ecosystems, pathogenic bacteria make us sick.

However, more interesting is that the same bacteria are used to produce medicines and treat bacterial diseases. They are exploited in the manufacture of various industrial products such as the production of antibiotics, probiotics, drugs, vaccines, starter cultures, insecticides, enzymes, fuels, and solvents. Read along to explore the possibilities and uses of bacteria in medicine.

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Useful Role of Bacteria in Medicine: Overview

Bacteria are omnipresent, microscopic, prokaryotic, single-cell organisms. They can be found even in some extreme conditions like in acid, in hot water springs, in anaerobic conditions, etc. even though some bacteria are extremely harmful, even deadly at times, human sickness is caused by fewer than one per cent of all bacteria kinds. The great majority of bacteria are non-toxic to humans, and certain kinds are even useful.

Beneficial microorganisms in the human gastrointestinal system help digestion and manufacture vitamins. They also aid immunity by making the body less welcoming to dangerous germs and viruses. Bacterial infection occurs when a hazardous strain of bacteria multiplies on or within the body. Bacteria have the ability to infect any part of the body.

Fig: Different Types of Bacteria

Medicinal Uses of Bacteria

Bacteria are exploited in the industry in a variety of ways, all of which make use of their innate metabolic capacities. Bacteria are utilized in the pharmaceutical sector to make antibiotics, vaccines, and therapeutically valuable enzymes.

Antibiotic

Bacteria are the major source of naturally occurring antibiotics. Bacteria that reside in the soil produce the majority of antibiotics. It is interesting to know that the discovery of the first-ever antibiotic was a great example of serendipity. Alexander Fleming discovered penicillin when the colony of Penicillium notatum accidentally contaminated the bacterial colony and killed all the bacteria. Later Waksman discovered streptomycin and began a new era of medicine. René Dubos, a French microbiologist, identified tyrothricin in \(1939\) and subsequently discovered that it was made up of two compounds, gramicidin \({\rm{(20\% )}}\) and tyrocidine \({\rm{(10\% )}}\). These were the first antibiotics to be commercially produced. Gramicidin is a heterogeneous combination of six antibiotic compounds derived from the Bacillus brevis soil bacterium species and together known as gramicidin D. Streptococcus is the most commonly used bacterial genus for the production of antibiotics.

Fig: Antibiotics

A list of bacteria and antibiotics obtained from them are given below:

Antibiotic	Source
Nystatin	Streptomyces noursei
Hamycin	Streptomyces pimprei
Bacitracin	Bacillus licheniformis
Streptomycin	Streptomyces griseus
Chloramphenicol Chloromycetin	Streptomyces venezuelae, S.lavendulae, and other streptomyces sp.
Tetracyclines	Streptomyces aureofaciens
Erythromycin	Streptomyces erythreus

Criteria for a Good Antibiotic:

(a) It should be able to destroy a wide range of disease-causing microbes (broad-spectrum antibiotics).
(b) It should not have any negative side effects.
(c) It should not harm the host’s usual flora.

Vaccine

Bacterial vaccines include microorganisms that have been killed or attenuated to stimulate the immune system. Antibodies are produced in response to that specific bacterium, and they help to avoid bacterial infection in the future. Bacterial vaccines are divided into various categories.

1. Toxoid: Toxoids are bacteria-produced toxins that have been chemically inactivated. These inactivated toxoids can effectively stimulate antibody formation and provide immunity against a particular infection. eg: Clostridium tetani 
2. Subunit vaccines/polysaccharide vaccines: A single pathogenic antigen is included in a subunit vaccine. The immunological response of a subunit is less than that of a full cell, but when no microbe is present, there is no risk of hyper-reaction or invasion. Example: vaccines are the vaccine against Salmonella typhi
3. Conjugate vaccines: To increase the immune response and alleviate the problem of a delayed T-independent immune response, conjugate vaccines were created by adding a protein to the capsular polysaccharide. streptococcus pneumonia
4. Inactive vaccines: Bacterial cells are eliminated in inactivated vaccinations. A chemical, heat, or radiation therapy is used to inactivate the organism that causes the illness. Example- a vaccine against V. cholera.
5. Live attenuated vaccine: Live vaccines are made out of attenuated, alive microorganisms. Attenuation can be achieved by forcing virulence-related genes to undergo random or targeted mutations. Example: vaccine against Mycobacterium tuberculosis
6. Recombinant vaccines: Recombinant vaccines are novel immunization techniques that utilize live attenuated bacteria as recombinant gene carriers. The creation of vaccines that are less reactive, more efficient, stronger, and better defined, as well as vaccinations that offer broader resistance against diverse types of bacteria, are the key rationale for recombinant protein-based vaccine manufacturing.
7. Serum From Bacterial Toxins:  Serum, in general, is blood plasma minus fibrinogen. Innate protection against microbial infections is provided by the serum complement system. Serums are used as a preventative strategy for illnesses including diphtheria, lockjaw, pneumonia, and others.
8. Preparation of serum: Small amounts of bacterial toxins are injected into the blood of animals to prepare serums. Antibodies are produced by the animal’s body to combat or neutralise bacterial toxins. The blood from the animal is drawn and is purified to eliminate blood corpuscles and other solid materials to obtain clear serum.
   The serum is obtained from genetically modified bacteria with human genes and the products are isolated from the culture. These can be used to treat various diseases. Some examples of serum extracted from bacterial cultures are blood clotting factor XIII for treatment of haemophilia A, Factor IX for haemophilia B, Antivenom for snake bite, etc.

Bio-enzymes

Enzymes are special macromolecules that are essential for all of the biochemical reactions that keep life going. Economic feasibility, high yields, consistency, simplicity of product modification and optimization, continuous supply owing to the absence of seasonal swings, quick growth of microorganisms on affordable media, stability, and increased catalytic activity are all reasons why microbial enzymes are favoured. Microbial enzymes are important in the diagnosis, therapy, biochemical inquiry, and monitoring of a wide range of disorders. Some important enzymes and their uses are listed below:

1. Amylase: It is one of the most commonly used bio enzymes, isolated from various microbes like Bacillus subtilis. Amylase levels that are greater than usual might indicate a variety of medical disorders, including acute pancreatitis, ruptured peptic ulcer, strangling ileus, torsion of an ovarian cyst, macroamylasemia, and mumps. The level of – amylase activity in various human bodily fluids is of clinical value, for example, in diabetes, pancreatitis, and cancer research.
2. Lipase: In the medical world, lipases are essential therapeutic targets or marker enzymes. Lipases can be utilized as a diagnostic tool since their presence or high levels might suggest an infection or sickness. Lipases can be utilized to help indigestion. Because lipases are tumour necrosis factor activators, they can be utilized to treat malignant tumours.
3. Asparaginase: Isolated from E. Coli, it is used in the treatment of leukaemia.
4. Streptokinase: It is isolated from Streptococcus sp. And used as clot busters in the treatment of blood clots formed in blood vessels. When certain parts of the blood thicken and form a semisolid mass, blood clots develop. An injury or a myocardial infarction that results in a heart attack might trigger this process.

Other Bioactive Molecules

The chemicals formed as a result of microbial activity are known as bioactive compounds. They can be in the form of enzymes, chemical compounds, probiotics, vitamins and organic acids.

Probiotics are living microorganisms that may enhance the host’s health. Probiotics are typically ingested as nutritional supplements or as part of fermented foods with specially added active living cultures, such as yoghurt and soy yoghurt. Probiotics are also used in faecal transplants, in which a healthy donor’s excrement is given to an infected patient as a suppository.

Fig: Probiotics

Some bioactive molecules, sources, and actions are listed below:

Bioactive molecule	Source	Action
Bacteriocins	Lactococcus lactis	Helps in the survival of bacteria in the GI tract. Kills various intestinal pathogens. Acts as signaling molecules
Entering	Enterococcus casseliflavus	Antimicrobial activity against Pseudomonas aeruginosa
Inulins	L. gasseri strains	Reduces fat absorption
Vitamin B1 (Thiamin)	Lactobacillus sps	Role in the synthesis of nucleic acids, steroids fatty acids, and amino acid precursors. All these bioactive compounds are essential for the functioning of the brain
Lactic acid	Lactobacillus sps	Used as the substrate for glucose, cholesterol, and lipids metabolism Lowers pH in the vaginal environment

Summary

Bacteria are omnipresent, microscopic, prokaryotic, single-cell organisms. Bacteria are utilized in the pharmaceutical sector to make antibiotics, vaccines, and therapeutically valuable enzymes. Bacteria are the major source of naturally occurring antibiotics. Streptomycin, Tetracyclines, Erythromycin, etc., are some of the major antibiotics obtained from bacteria. Bacterial vaccines include microorganisms that have been killed or attenuated to stimulate the immune system. Some types are toxoids, subunit vaccines, conjugate vaccines, inactivated vaccines, live vaccines, and Recombinant vaccines.

Enzymes are special macromolecules that are essential for all of the biochemical reactions that keep life going. Microbial enzymes are essential in diagnosing, therapy, biochemical inquiry, and monitoring a wide range of disorders. Amylase, lipases, and Streptokinase are some necessary microbial enzymes.The chemicals formed as a result of microbial activity are known as bioactive compounds. They can be in the form of enzymes, chemical compounds, and organic acids. Bioactive molecules like lactic acid, inulin, enterocins, etc., are used for various medicinal purposes.

FAQs on Useful Role of Bacteria in Medicine

Q.1. What is the role of bacteria in antibiotics?
Ans: Bacteria like Streptococcus are used to produce antibiotics which helps fight against various bacterial infections in humans and other animals.

Q.2. What are the useful roles of bacteria?
Ans: Bacteria can be used in the pharmaceutical industry, agricultural industry, bakery, brewery, chemical industry, etc.

Q.3. Name three bacterial antibiotics.
Ans: Streptomycin, Tetracyclines, Erythromycin are three bacterial antibiotics.

Q.4. Name the first bacterial antibiotic obtained from bacteria.
Ans: Tyrothricin was the first bacterial antibiotic obtained from bacteria.

Q.5. Name three bioactive molecules naturally produced by bacteria in the human body?
Ans: Lactic acid, inulin, Vitamin \({{\rm{B}}_{12}}\)

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