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Bacteria hate this one viral trick! Bacteriophages against antibiotic resistance.

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Nima Soleimani

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Before the advent of modern medicine, bacterial infections ravaged human society. A lack of treatment options available rendered infections such as bacterial pneumonia deadly.

However, an accidental discovery would lead to the development of bug-fighting medications known as antibiotics. In 1928, Physician Alexander Fleming was studying the bacterial genus Staphylococcus by cultivating it in petri dishes before leaving for a summer vacation (Gerberi, 2024). When he returned, he noticed that one of his petri dishes was now infected with mold, the area surrounding the growth completely bacteria-free. The antibacterial agent the mold produced is known as penicillin, the very first antibiotic to be isolated (Gerberi, 2024).

Figure 1. The skeletal structure of penicillin G (benzylpenicillin). Penicillin G is a commonly used penicillin or β-lactam antibiotic (NIH 2026).

The many antibiotics available today have different molecular structures that allow them to target various bacterial functions while leaving human cells unharmed. Penicillins weaken the bacterial cell wall by inhibiting the transpeptidase that cross links peptidoglycans in the bacterial cell wall, causing the cell wall to fall apart leading to cell death (Yocum et al. 2021). The β-lactam ring in penicillin is responsible for the enzyme binding.

However, humanity may be falling out of its honeymoon phase with antibiotics as cracks begin to show. Increasingly, overuse of antibiotics in agriculture and healthcare has led to the selection of antibiotic-resistance genes in bacteria, creating super-bugs that have developed mechanisms to defend against antibiotics (Olawoyin et al. 2026). If unaddressed, bacterial infections would become harder to treat.

Like antibiotics, bacteriophages are another treatment which can be used for bacterial infections. Bacteriophages are viruses which infect bacteria as part of their life cycle. Phage therapy has been used to treat infections since the early 20th century, before the advent of antibiotics (Ganeshan et al. 2019). Unlike antibiotics which can target multiple types of bacteria, bacteriophages are highly specialized to target their prey bacteria, leaving helpful or harmless bacteria behind. The viral life cycle varies but always involves injection of the viral genome into the host cell genome. Transcription and translation of the genome then assembles new viruses that can infect other cells (Ganeshan et al. 2019). A major advantage to phage therapy is that it can effectively treat antibiotic-resistant bacterial infections. Additionally, the large selection of bacteriophages available means that new phages can be isolated even when bacteria develop resistance (Ganeshan et al. 2019).

Phage therapy introduces unique challenges as opposed to antibiotics. Individual bacteriophages are hyper-specific to their host bacteria, whilst individual antibiotics can target many strains of bacteria (Ganeshan et al. 2019). Critically, bacteriophages haven’t received the same R&D as antibiotics in western medicine. Issues with phage collection and distribution are still major roadblocks in treating infections with phage therapy (Ganeshan et al. 2019).

There is no perfect, cure-all treatment for any medical complication, much less a bacterial infection. Nonetheless, bacteriophage and antibiotic co-administration can help to impede treatment-resistant bacteria prevalence. It is unlikely that bacteriophages will completely replace antibiotics, but they host unique benefits that make them bound to go viral.

References

Divya Ganeshan, Sharita, and Zeinab Hosseinidoust. 2019. “Phage Therapy with a Focus on the Human Microbiota” Antibiotics 8, no. 3: 131. https://doi.org/10.3390/antibiotics8030131

Gerberi, Danielle. 2024. “Alexander Fleming: A Second Look.” Journal of the Medical Library Association 112 (1): 55–59. https://doi.org/10.5195/jmla.2024.1780.

Olawoyin Damilare, Mushapha Lukman, Obayomi Oluwatobi, and Obayomi Kehinde. 2021. “Foodborne and environmental biofilms as drivers of antimicrobial resistance: A one health perspective.” Environmental Research 306 (125375): 1-24. https://www-sciencedirect-com.libaccess.lib.mcmaster.ca/science/article/pii/S0013935126017068?via%3Dihub#abs0010

PubChem, “Penicillins,” PubChem, n.d., https://pubchem.ncbi.nlm.nih.gov/compound/2349.

Yocum, James Rasmussen, and Jack Strominger. “The Mechanism of Action of Penicillin.” The Journal of Biological Chemistry 255 No. 3 (January 2021): 3977-3986. https://www.sciencedirect.com/science/article/pii/S0021925819856211?via%3Dihub

Comments

3 Responses to “Bacteria hate this one viral trick! Bacteriophages against antibiotic resistance.”

  1. Nima Soleimani Avatar
    Nima Soleimani

    Hi all,
    Thank you for reading my post focused on the disciplines of biology and chemistry! I decided to cover this topic after attending a webinar on phage therapy hosted by McMaster’s own Dr. Hosseinidoust. I found the new R&D being done to be an innovative way to tackle an emerging issue that can have serious impacts on healthcare and agriculture. I also think that the evolution of antibiotic-resistant traits in bacteria due to the selective pressure of antibiotics intersects well with the topic of evolution learned in life science recently.
    I am worried that my blog is too oriented on biology, so I am debating using ~50 words to discuss the green (or not so-green) chemistry related to antibiotics. We learned in chemistry recently that pharmaceuticals have poor sustainability metrics such as E-factor, and Dr Hosseinidoust’s publications mention this explicitly.
    Please, if you have any suggestions let me know. I am looking forward to hearing your thoughts!

  2. Julianna Scherer Avatar
    Julianna Scherer

    Hi Nima,

    The story of the discovery of penicillin was so interesting to learn about! It was neat to learn about the potential co-administration of antibiotics and bacteriophages. Below are a few suggestions to help with your editing process:

    – In your second paragraph, I don’t think “Physician” needs to be capitalized
    – You should refer to your figure in text so the readers know what it correlates to
    – In your second last paragraph, I think you should say “research and discovery” rather than “R&D” to help increase reader understanding
    – You should format your references so it is a heading and stands out from the rest of your text
    – For your Damilare citation, you should find a DOI link that doesn’t require the McMaster library. As well, for your Rasmussen citation, you should find the DOI rather than the science direct link.

    Happy editing!
    Julianna

  3. Aveline Desousa Avatar
    Aveline Desousa

    Hi Nima,

    I really enjoyed reading your post! I thought your explanation of the mechanisms behind both antibiotics and phage therapy was very informative and well written. Here are some suggestions that I hope will be helpful to your editing process:

    – You mentioned co-administration at the end of your post, however it may be beneficial to mention that earlier on so you could describe this more in depth which creates the opportunity for the connection to green chemistry that you were looking to expand upon
    – In your last paragraph, you write “much less,” which is shortly followed by “Nonetheless.” I think one of these could be replaced with a synonym to avoid similar wording, such as replacing “much less” with “let alone,”
    – Your second paragraph might flow better if you connect two of the sentences together, I’d suggest putting an “and” between the last 2 sentences in that paragraph

    I hope you find these suggestions helpful, great work!
    – Aveline

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