By Tania, Winter 2022.
When walking into the first lecture of a new quarter, a student does not typically expect to be greeted with the professor’s biggest fear listed at the top of the syllabus. Yet students in Organic Chemistry this quarter got more than they bargained for when they learned about the most terrifying words known to organic chemists everywhere: antibiotic resistant bacteria. These bugs are like many other human pathogens, except sometimes the life-saving drugs modern medicine uses to treat them stop working. The most common of these “superbugs,” called MRSA, causes about a hundred thousand deaths every year[1]. With such devastating impacts on global health, it has become necessary to take a closer look at this bacteria.
Figure 1: An informational poster on MRSA displayed at Ratner Athletic Center. |
Information on MRSA, or methicillin-resistant Staphylococcus aureus, is easier to find than one might think. On UChicago’s campus, a simple trip to the Ratner Athletic Center reveals multiple posters explaining what the disease is and how to prevent its spread. MRSA’s namesake belongs to a genus of bacteria called Staphylococcus. [2] These bacteria attach to the outer cell membrane of human cells, leading to a localized infection. In time, these bacteria replicate and spread throughout the body. Symptoms can include sores, pus-filled bumps on the skin, and, in serious cases, days-long fevers. Normally, these bacteria can be stopped with the correct antibiotic drug, which in most cases is methicillin. However, MRSA cells have learned to avoid this drug.
If we can’t stop the MRSA pathogen once it is in the body, the best course of action may be to prevent its entry. However, this is not as simple a task as it may sounds. MRSA cells are an extremely prevalent type of bacteria. It is estimated by the CDC that 5% of hospital patients carry MRSA on their bodies. [3] They are also commonly found on public pool floors, in locker rooms, playgrounds, and daycare centers. With this degree of prevalence, the best defense against MRSA bacteria is maintaining good hygiene, including washing one’s hands and showering regularly. Additionally, keeping exposed wounds covered prevents MRSA from entering the human body. However, even the most germ-conscious are vulnerable to this very serious infection.
Besides its prevalence, the main danger posed by MRSA is its resistance to modern antibiotics. It is classified as one of the 5 main “superbugs”: drug-resistant bacteria which result in more deaths per year than HIV/AIDS. The development of this drug resistance was a long process, and one that may have been humanity’s fault. After the commercialization of antibiotics in the mid-1900s, doctors across the country were quick to prescribe antibiotics for many minor ailments. Every time a strain of bacteria is exposed to these drugs, there is a possibility of it mutating to resist the drug’s attacks. Over time, these small mutations allow the bacteria to survive antibiotic treatment and pass these traits down to future infecting cells. This problem has only been exacerbated by the over-prescription of antibiotics to both humans and livestock. Additionally, when we don’t correctly follow the instructions for prescription antibiotics, we can leave behind a small amount of bacteria in our bodies, causing an infection. These bacteria have already been exposed to the antibiotic and survived, passing this trait down to their offspring. In sum, the more exposure these bacteria get to the drugs designed to fight them, the more likely it is they will mutate to survive.
MRSA is a particularly insidious superbug due to characteristics that allow it to quickly adapt to antibiotics. First, the doubling time of MRSA is only 2 hours, meaning that a new offspring cell is made from a parent in a very short time frame. Each time a cell divides and replicates, its DNA has a chance to mutate. With so many chances for a drug-resistant mutation, it’s no surprise that MRSA can very quickly adapt to render a drug useless. Another characteristic is in MSRA’s genes themselves. Scientists have narrowed down the possible genes serving as sources of drug resistance. A 2002 study found that 11 clones in 5 genotype groups are responsible for this type of mutation. [4] Because there are many possibilities for a genetic mutation, it is difficult for scientists to keep up with the specific genes being targeted. As these bacteria become better at fighting the drugs we use to treat them, we are left scrambling in a game of catch-up where the rules change every time we near the finish line.
Luckily for my organic chemistry professor, there are many possible solutions to the antibiotic resistance crisis. First, we can simply improve antibiotic usage in humans. Doctors should only prescribe antibiotics when necessary, an important lesson that medical schools across the country are already incorporating into their curriculum. When prescribing these drugs, doctors should educate their patients on the importance of using targeted prescriptions to their fullest extent. A full course of antibiotic treatment is designed to kill off any lingering pathogens. [5] Using the drugs correctly leads to a smaller probability that a resistant bacteria cell will pass on its mutations to its children.
A second solution comes in the form of reducing the amount of antibiotics in our environment. [6] For example, Denmark has attempted to ban antibiotics when raising livestock to counter the amount of antibiotics given to livestock in a year. They hoped this would reduce human exposure to antibiotics, which frequently end up in our food and bodies. The ban, enforced through a combination of fines, inspections, and “yellow cards” given to farms that didn’t meet standards, resulted in a 50% reduction in antibiotic presence in meat products. Although data is still being collected, researchers hope this reduction will aid in stopping the spread of superbugs in Denmark.
Lastly, if bacteria keep evolving to resist antibiotics, then our solution must be to find other ways to treat bacterial infections. In a recent Cornell study, it was found that treating serious MRSA infections with stem cells aids the immune system when fighting the bacterial invaders. [7] Stem cell treatment also helps the immune system recognize MRSA cells more quickly, allowing doctors to offer better treatments to patients. Because this treatment relies on living cells and not drugs, it could evolve alongside the bacteria to fight against it. The study shows promising results, with many participants making a painless and quick recovery. However, it is not yet an efficient method as it can be hard to direct the stem cells to the MRSA-infected site.
Superbugs like MRSA are quickly becoming the main cause of concern amongst drug developers. MRSA’s prevalence and refusal to be killed by many modern drugs makes it a threat to everyday people’s health across the globe. However, with this disease also comes tangible solutions and promising research on how to be one step ahead of the bacteria’s mutations. In a few years’ time, maybe my professor will be able to move on to a different fear.
[1] Dixon-Luinenburg, Miranda. 2022. “The hidden epidemic.” Vox, February 16, 2022. https://www.vox.com/future-perfect/22922018/antibiotic-resistance-epidemic-drug-resistant-infections
[2] Harris LG, et al. 2002. “An introduction to Staphylococcus aureus, and techniques for identifying and quantifying S. aureus adhesins in relation to adhesion to biomaterials: review.” Eur Cell Mater 4: 39-60. doi: https://doi.org/10.22203/ecm.v004a04.
[3] CDC. 2019. “General Information.” Methicillin-resistant Staphylococcus aureus (MRSA). Last modified June 26, 2019. https://www.cdc.gov/mrsa/community/index.html.
[4] Enright, M.C.,et al., 2002. “The evolutionary history of methicillin-resistant Staphylococcus aureus (MRSA).” PNAS 99, no 11: 7687–7692. Doi: https://doi.org/10.1073/pnas.122108599.
[5] NIH. 2014. “Stop the Spread of Superbugs.” NIH News in Health. February 2014. https://newsinhealth.nih.gov/2014/02/stop-spread-superbugs.
[6] Jacobs, Andrew. 2019. “Denmark Raises Antibiotic-Free Pigs. Why Can’t the U.S.?” New York Times. December 6, 2019. https://www.nytimes.com/2019/12/06/health/pigs-antibiotics-denmark.html#:~:text=In%20the%20years%20that%20followed,most%20essential%20drugs%20for%20humans.
[7] 2021. “Researchers explore promising treatment for MRSA ‘superbug’.” Cornell Chronicle. September 16, 2021. https://news.cornell.edu/stories/2021/09/researchers-explore-promising-treatment-mrsa-superbug.