5.3 Chemical modification
For many years, scientists have chemically modified antibiotics incrementally, broadening the spectrum of activity and increasing effectiveness and usability. This usually reverses antibiotic resistance at the same time. This happens with the cephalosporins, which are discussed in Section 6.
In the next activity, you will learn about a single, specific modification that could potentially reverse resistance by making the antibiotic more powerful.
Activity 4 Making antibiotics more powerful
First, read the short article below about a promising new way of overcoming antibiotic resistance. Then complete the table comparing the characteristics of the two antibiotics vancomycin and oritavancin.
Article 1: ‘Brute force’ can overcome antibiotic resistance (UCL, 2017). [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)]
| Characteristic | Vancomycin | Oritavancin |
|---|---|---|
| Therapeutic use | ||
| Killing mechanism | ||
| Time taken to kill a bacterial cell |
Answer
| Characteristic | Vancomycin | Oritavancin |
|---|---|---|
| Therapeutic use | Last resort treatment for MRSA | Complex skin infections |
| Killing mechanism | Disrupts vital cellular processes | Clusters latch onto bacterial surface and then push apart, generating a strong force that ruptures the cell. |
| Time taken to kill a bacterial cell | 6–24 hours | 15 minutes |
Now answer the following questions, based on the article.
- Which is the more powerful antibiotic and why?
- How do the scientists plan to use their findings in future research?
Answer
- Oritavancin is more powerful. The force used by oritavancin to push into a bacterial cell is 11 000 times more powerful than that of vancomycin.
To help inform the design of new antibiotics, and to make similar modifications to existing antibiotics, in order to make them more powerful
Next, you will look at the modifications that have been made to different generations of cephalosporins.