Antibiotics are chemicals that kill or stop the growth of bacteria and fungi. They are naturally produced by these microorganisms to compete for limited resources like water and food. Antibiotics have been widely used in medicine for years because they can kill bacteria without harming human cells. However, antibiotics are also used for other purposes beyond medicine. The use of antibiotics has had a huge impact on the treatment of diseases and infections.

The uses of antibiotics

As mentioned, the most widely known use of antibiotics is in therapeutics to treat medical conditions caused by bacteria. However, this is not the only use. Antibiotics are used in microbial culture, farming, food preparation, building, domestic products and several other areas.

Antibiotic use in medicine

Antibiotics are essential drugs used in medicine to treat bacterial infections. They work by either stopping the growth or killing bacteria. There are two types of antibiotics: bacteriostatic and bactericidal. Bacteriostatic antibiotics stop bacterial growth, while bactericidal antibiotics kill bacteria outright.

There are different classes of antibiotics used in therapeutics. Penicillin, discovered8, is one of the most famous antibiotics and the first to be discovered. It became widely available in the 1940s and revolutionised modern therapeutic medicine.

Using antibiotics inappropriately is a major cause of antibiotic resistance, which occurs when antibiotics are unable to kill or prevent the growth of an entire population of bacteria. Incorrect use includes using antibiotics to treat viruses or not completing the full course of antibiotics prescribed. Antibiotic stewardship is the appropriate use of antibiotics to maintain their effectiveness.

It's important to note that antibiotics only work against bacteria and not viruses. To treat viral infections, antivirals are required.

Antibiotic resistance is a serious challenge in therapeutics today. Learn more about this issue in our article on Antibiotic Resistant Bacteria.

The uses of antibiotics in agriculture

Antibiotics are used and abused in many areas of farming, some for good reason and others less so. Around 66% of antibiotics manufactured yearly are used in animals. Antibiotic use in farming is another major source of antibiotic resistance.

Antibiotics in animal farming

Antibiotics are used in animal farming for the legitimate use of treating animal infections. In this case, antibiotics are used similarly to human medicine. The other major use of antibiotics in animal farming is as growth promoters. In this case, antibiotics are introduced at sub-therapeutic doses (lower than the medical dose) through the animals' food and water. This causes them to grow quicker. The exact mechanisms behind this are not precisely known; however, it is believed to be a result of either the killing of gastrointestinal bacteria, which consume nutrients that could otherwise be used for growth, or the prevention of infections that cause limited growth.

The use of antibiotics as growth promoters is illegal within the European Union (EU); however, up until 2017, it was common practice in the USA and is still ongoing elsewhere. Antibiotic growth promoters help farmers by increasing the conversion rate of feed to animal products, meaning they get more products for their investment in feed. However, as the exposure is sub-therapeutic, it creates a perfect environment for developing antimicrobial resistance by presenting a consistent selection pressure to bacteria within the animals. This is especially concerning as many microbes present in animals are also human pathogens, meaning resistance that arises in animals can easily transfer to human pathogens either directly or through the transfer of genetic material.

Antibiotics are also used prophylactically to prevent infection, operating on the principle that animals can't get sick if the bacteria that cause the infections are killed before they can cause an infection. This is used when animals are raised in tightly packed, less clean conditions.

Prophylactics are medicines given to prevent rather than treat disease. Medicine provided in this manner is said to be given prophylactically. An example of a prophylactic is the pre-exposure medicine given to those at risk of contracting HIV to prevent infection.

Antibiotics in horticulture

Antibiotics are also used in horticulture to treat plant diseases. They are typically applied prophylactically via sprays as application after infection is usually ineffective. However, this practice presents another avenue for developing antimicrobial resistance due to the release of antibiotics into the environment. Antibiotics can enter the environment through overspray that does not land on the plants or when rain washes the drugs into the surrounding environment.

This release of antibiotics into the environment can have negative ecological consequences, such as the development of antibiotic-resistant bacteria in soil and water, which can have a knock-on effect on plant and human health. Therefore, it is essential to use antibiotics judiciously and only when necessary to prevent the development of antimicrobial resistance in horticulture.

Antibiotics in fish farming

Antibiotics are also commonly used in fish farming or aquaculture as a preventative measure to minimize sickness in farmed organisms. Similar to antibiotic use in animal farming, this measure is used to protect profits and prevent disease outbreaks, which can be exacerbated by the high stocking levels usually present in aquaculture.

However, the use of antibiotics in fish farming presents a risk of antibiotics being released into the surrounding environment, as the organisms may be raised in artificial habitats that are not completely isolated from the natural environment. The risk of antibiotic release depends on the method used, with tanks presenting the lowest risk as the water is entirely isolated from the environment, and appropriate treatment can prevent antibiotic release.

Ponds and raceways present a higher risk of antibiotic release, as the water may still be processed to prevent antibiotic release, but the in-ground nature increases the likelihood of accidental release. Enclosing natural water areas, such as shallow, near-shore waters or pens in deep, open water, presents the largest risk of antibiotics being released into the surrounding ecosystem, as the water is simply part of the natural body, separated only by the mechanism used to contain the farmed.

Therefore, it is judiciously in fish farming and aquaculture and to implement appropriate measures to prevent the release of antibiotics into the environment.

Antibiotics in insect farming

Like animals, insects are susceptible to infection by bacterial pathogens. While a variety of insects are cultivated for the production of human foodstuffs, the most common globally is the honey bee. So these present the main use of antibiotics in insect farming. Insects are also farmed for non-human foodstuffs, including for use as animal feed, which may lead to antibiotics being inadvertently passed on to other areas.

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Some beekeepers use antibiotics at sub-therapeutic levels, similar to the use of antibiotics as growth promoters in animals, to increase product output. However, this practice can create a selection pressure that encourages the development of antimicrobial resistance. Additionally, many insects have limited metabolism of antibiotics, which means a significant proportion of the dose can be passed on through the consumption of the insects or their products, such as honey.

The use of antibiotics in beekeeping is a concern because bees are crucial pollinators for many crops, and the development of antibiotic-resistant bacteria in bees could have significant consequences for both human health and the environment. Therefore, it is essential to use antibiotics judiciously and only when necessary to prevent the development of antimicrobial resistance in beekeeping. Additionally, alternative methods of disease prevention, such as improving hive hygiene and using natural remedies, should be explored to reduce the reliance on antibiotics in beekeeping.

Uses of antibiotics in shipping

Antibiotics, specifically tetracyclines, are commonly used in anti-fouling paints for ships to prevent biofouling. Biofouling occurs when organisms attach to a ship's surface by forming a bacterial biofilm, which can slow down the ship and increase fuel consumption. Biofilms are colonies of microorganisms held together by polymers, which protect them from environmental stressors and enable them to share nutrients.

Biofouling occurs in several stages, beginning with the attachment of organic polymers to the surface, which provides a substrate for bacteria and diatoms to colonize and form afilm.gae and protoa then attach biofilm, facilitating the colonization of larger organisms like barnacles. By adding antibiotics to the paint, the bacteria that form the biofilm can be killed, which slows or halts the formation of the fouling community.

While using antibiotics in anti-fouling paints may be effective, it is important to consider the potential environmental consequences. The release of antibiotics into the environment can contribute to the emergence of antimicrobial resistance, which is a significant global health concern. Therefore, it is important to use antibiotics judiciously and explore alternative methods of preventing biofouling, such as physical barriers or non-antibiotic-based coatings.

The uses of antibiotics in microbial culture

The use of antibiotics several benefits. it prevent bacterial contamination, which is a significant threat to the success of microbial cultures. By adding antibiotics to the culture medium, bacterial growth can be inhibited, allowing for the growth of the target microorganism.

Secondly, antibiotics can be used when modifying microorganisms. By including a resistance gene for a specific antibiotic within a vector, bacteria that have successfully taken up the genetic material can be selected for, while those that have not can be killed by the antibiotic. This allows for the creation of a pure culture of successfully modified bacteria. Lastly, antibiotics can be used to study the effects of antibiotics on microorganisms. By exposing microbial cultures to different antibiotics, researchers can study the mechanisms of action of these drugs and better understand how they work. Overall, the use of antibiotics in microbial cultures can help ensure the success of the culture and the purity of the end product, as well as aid in research on the effects of antibiotics on microorganisms. However, it is important to use antibiotics judiciously and with consideration for the potential development of antibiotic resistance.

Both the medical and non-medical applications of antibiotics present several benefits.

The use of antibiotics has many benefits in various fields. In animal farming, antibiotics are used as growth promoters to increase efficiency and profitability. Prophylactic administration also helps prevent disease, improving the health and wellbeing of the animals.

In medicine, antibiotics have revolutionised treatments and have saved countless lives by treating bacterial infections. In the past, bacterial infections could be life-threatening, but with the use of antibiotics, they have become mere inconveniences that can be managed with relative ease.

In shipping, the use of antibiotics in anti-fouling paints helps prevent biofouling, which can slow down ships and increase fuel consumption. By preventing biofouling, the cost and emissions associated with shipping are reduced, making it a more efficient and sustainable industry.

Finally, the use of antibiotics in microbial culture helps prevent bacterial contamination, allowing for more efficient culture, selecting successfully modified organisms, and producing pure cultures of microorganisms.

While the use of antibiotics has many benefits, it is crucial to use them judiciously and with consideration for the potential development of antibiotic resistance. Overuse or misuse of antibiotics can lead to the emergence of antibiotic-resistant bacteria, which can pose a significant threat to human and animal health. Therefore, it is essential to use antibiotics only when necessary and to explore alternative methods of prevention and treatment.

Consequences of antibiotic use

Yes, you are correct. The use of antibiotics in non-med areas, such as agriculture and animal farming, can have significant consequences, including the development of antibiotic resistance and the release of antibiotics into the environment, leading to antibiotic pollution. Improper use of antibiotics creates a selection pressure that selects for mutations conveying resistance, which can then spread to other bacteria and reduce the effectiveness of antibiotics.

In animal farming, antibiotics are used as growth promoters and prophylactically to prevent disease before an outbreak occurs. The use of antibiotics in horticulture, aquaculture, and insect farming is also prevalent to prevent infection and limit disease.

However, the unsupervised use of antibiotics in these areas increases the likelihood of incorrect doses being used, leading to antibiotic resistance. Additionally, the release of antibiotics into the environment through agricultural runoff or other means can significantly alter the natural bacterial population in an area, increasing the likelihood of resistance developing.

Furthermore, antibiotic pollution can also affect the food chain, leading to accidental exposure of humans to antibiotics through the contamination of foodstuffs. This is further exacerbated by bioaccumulation, where a substance accumulates in an organism from its surrounding environment, food, and water.

Therefore, it is crucial to use antibiotics judiciously and with consideration for the potential development of antibiotic resistance, and explore alternative methods of prevention and treatment in non-medical areas to mitigate the effects of antibiotic pollution.

Use of Antibiotics

What are antibiotics used for? 

Antibiotics are used for controlling the impact of bacteria by either killing them or halting their growth. 

What percentage of antibiotics are used in agriculture? 

Around 66% of annual global antibiotic production is used in animals instead of human medicine. 

What are the main uses of antibiotics? 

The main use of antibiotics is to control disease, however they may also be used to prevent contamination in microbial culture or to increase the growth rate of animals. 

Why are antibiotics used in animal feed? 

Antibiotics are added to animal feed and water to prophylactically prevent disease due to the cramped confines and poor sanitation often present in farming. They also may promote more rapid growth via poorly understood mechanisms. This means a higher feed conversion rate and  more profit for the farmer. 

Why are antibiotics used in agriculture? 

Antibiotics are used in agriculture to prevent disease through prophylaxis, cure disease or promote growth in animals.

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