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  • Medha Shinde
    • Jun 13
    • 4 min read

Antibiotic Resistance

Since Penicillin was discovered in 1928, the use of antibiotics for the treatment of diseases has increased exponentially; commonly prescribed antibiotics are becoming less effective for several reasons:

  • overuse of antibiotics

  • failing to complete the fully prescribed course by a doctor

  • use of antibiotics in farming

These can lead to the reduction of the effectiveness of antibiotics and the increase in the incidence of antibiotic resistance. These bacteria are commonly known as superbugs. When people visit the doctor because they feel ill, they anticipate receiving an antibiotic prescription. Antibiotics are pointless and ineffectual if people suffer from viral diseases, like the common cold, rather than bacterial infections. Patients should always take antibiotics to the end every time antibiotics are prescribed. By doing this, it is ensured that no bacteria survives and can evolve to generate strains of resistance. After taking the medication for a few days, patients start to feel better and discontinue. Antibiotic resistance may result from random mutations, which makes this potentially extremely dangerous. Rapid reproduction of the resistant bacteria causes the resistance to spread. In the past, farming frequently employed antibiotics, which help keep livestock healthy, stop sickness, and promote rapid growth. Antibiotic resistance in humans may result from the extensive use of antibiotics in agriculture, which could have a cost. To try to lower the usage of antibiotics in this way, legislative limits have been put in place.


Why is antibiotic resistance a problem?


Antibiotics may no longer work because the bacteria they are intended to kill are becoming resistant. Most of the deaths from AMR (Antimicrobial Resistance) were caused by lower respiratory infections, such as pneumonia, and bloodstream infections, which can lead to sepsis (Sepsis is a severe condition that happens when the body’s immune system has an extreme response to an infection. The body’s reaction causes damage to its tissues and organs.) 

MRSA (methicillin-resistant Staphylococcus aureus), a type of bacteria resistant to several antibiotics, is particularly deadly, while E. coli and several other bacteria were also linked to high levels of drug resistance. MRSA can cause severe problems like bloodstream infections, pneumonia, or surgical site infections. MRSA usually spreads in the community through contact with infected people or things carrying the bacteria. This includes contact with a contaminated wound or sharing personal items, such as towels or razors, that have touched infected skin. The opioid epidemic may also be connected to the rise of staph infections in communities. People who inject drugs are 16 times more likely to develop a severe staph infection. 



Some antibiotics, their modes of action, and how they lead to resistance are listed below:

  • Penicillin (beta‐lactams) competitively inhibits penicillin-binding proteins, which are required for peptidoglycan synthesis, which makes up the bacterial cell wall. This disrupts the cell wall and thus affects its water potential, meaning the cell might burst or shrivel up. Without the action of penicillin-binding proteins, bacteria upregulate autolytic enzymes and cannot build and repair the cell wall, leading to bactericidal action (kills bacteria).


Antibiotic resistance to penicillin is caused by drug inactivation (There are two main ways bacteria inactivate drugs: by actual degradation of the drug or by transfer of a chemical group to the drug. The β-lactamases are an extensive group of drug-hydrolyzing enzymes). Protective enzymes produced by the bacterial cell will add an acetyl or phosphate group to a specific site on the antibiotic, reducing its ability to bind to the bacterial ribosomes and disrupt protein synthesis. 


  • Erythromycin (macrolides) is another antibiotic that inhibits protein synthesis by binding to bacterial ribosomes. It is thought to bind to the 50S subunit of the ribosome. Erythromycin's antibiotic resistance is caused by target site insensitivity, e.g., changes to the ribosome in erythromycin resistance—methylation of the ribosomal drug binding site, which mediates resistance to macrolides like erythromycin.


  • Aminoglycosides are another group of antibiotics, e.g., gentamicin, tetracycline, and streptomycin. They work by disrupting peptide elongation at the 30S ribosomal subunit, making mRNA production inaccurate and forming truncated proteins or proteins with altered amino acid sequences. 

Antibiotic resistance of aminoglycosides is caused by efflux, where resistance genes encode a membrane protein that actively pumps tetracycline out of the cell in exchange for a proton.



Ways to overcome antibiotic resistance


There are many options to avoid antibiotic resistance. For example, healthcare providers can help by treating infections more specifically e.g. by testing the sensitivity of a pathogen to antibiotics and then only treating in relation to this. Targeting the medicine as soon as possible to the specific bacteria involved, prescribing medication for only as long as needed. From the patient's side, they should only take antibiotics exactly as prescribed. Don’t skip doses. Complete your entire course of treatment even if you are feeling better. Patients begin to feel well after a few days of taking the medicine and stop taking them. This is potentially harmful, as random mutations can lead to antibiotic resistance. The resistant bacteria reproduce quickly, and the resistance spreads. Finally, better antimicrobial guidance e.g. only giving people antibiotics when they need them, not just when people ask for them. 


Reference List



Antibiotic resistance - Treating, curing and preventing disease - AQA - GCSE Biology (Single Science) Revision - AQA [WWW Document], n.d. . BBC Bitesize. URL https://www.bbc.co.uk/bitesize/guides/z8fkmsg/revision/4 (accessed 4.22.24).


Articles [WWW Document], n.d. . Cedars-Sinai. URL https://www.cedars-sinai.org/health-library/articles.html (accessed 4.22.24).


Erythromycin [WWW Document], n.d. URL https://go.drugbank.com/drugs/DB00199 (accessed 4.22.24).


General Information | MRSA | CDC [WWW Document], 2019. URL https://www.cdc.gov/mrsa/community/index.html (accessed 4.22.24).


How Do Aminoglycosides Work? - Uses, Side Effects, Drug Names [WWW Document], n.d. URL https://www.rxlist.com/how_do_aminoglycosides_work/drug-class.htm (accessed 4.22.24).


Reygaert, W.C., 2018. An overview of the antimicrobial resistance mechanisms of bacteria. AIMS Microbiol. 4, 482–501. https://doi.org/10.3934/microbiol.2018.3.482


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