Isolation of Staphylococcus epidermidis from Water Bottle
by Sophia Macander
Description: In this paper I discuss how I collected, isolated, and characterized the bacterium Staphylococcus epidermidis that I found in a water bottle my roommate left over winter break.
Read my paper here: Link
Article & Link: In India, a Renewed Fight Against Leprosy (The New York Times; April 17, 2019)
Summary: Leprosy, which is caused by Mycobacterium leprae has been eliminated throughout most of the world. However, it is still a huge problem in India, which currently has 60% of all leprosy cases in the world. This is largely due to the stigma against people with leprosy in India, who are not allowed to have jobs or even be in public if they have the disease. This means people with leprosy won’t seek help if they have leprosy, which causes nerve and muscle damage if it isn’t treated. However, there are some doctors in India who are trying to educate people better on leprosy to treat as many people as possible and hopefully prevent its further spread in India.
Connections: We were recently learning about pathogens in class. Leprosy, or Mycobacterium leprae causes a bacterial disease which affects nerves and muscles. The article mentioned that the bacterium is not culturable which prevents understanding of the disease. This explains why scientists don’t yet understand how the disease spreads. It sometimes spreads in a seemingly random way, infecting some people but not others. Furthermore, people can carry the disease for decades, spreading it to other people without realizing they are carriers.
Critical Analysis: I found the discussion about non-culturable pathogenic bacteria very interesting, because most of the examples we learned about in class were discovered and treated through culturing. It is also interesting to see how stigma and misinformation prevents treatable diseases from being eliminated. I learned a lot about how India’s culture regarding leprosy by reading this article. Many people hide it, potentially risking the health of those around them. Others go to leprosy colonies, or secluded communities, surviving by begging and helping each other. From what I could tell this article appeared to be scientifically accurate and not misleading. I feel like the writing is both accessible and informational to general audiences. It explains what leprosy is, the common symptoms, and why it’s such a big problem in India. I think it also did a good job explaining why leprosy is hard to study (mentioning its non-culturable, explaining it can’t be found by blood tests, and talking about how people can be carriers for decades) to people who may not have a lot of previous microbiology background.
Question: How should/do doctors and scientists study non-culturable bacterial species? Especially those species that are pathogenic?
My piece is called Barriers. It depicts several types of innate resistance the body uses. The first half of the piece depicts common microbes found on the skin. Skin is a very important part of innate resistance, because it provides a barrier between microbes and sterile parts of the body including the blood and muscles tissue. I used acrylic paint for the first piece and painted microbes on water color paper. Pink and purple paint were used depending on if they are Gram positive or Gram negative. For skin I colored paper a skin tone to represent skin, though it didn’t show up very well in photographs. The microbes I depicted were Staphylococcus, Corynebacteria, and Micrococcus species, which are commonly found on the skin. The second part of my piece depicts how the enzyme lysozyme breaks down bacterial cell walls. Lysozyme is also an important part innate resistance, because it prevents bacteria from getting into the eyes and causing infections. I used colored pencils and water colors for this part of the piece. The colored pencils were used for outlining and shading, and the water colors were used to fill in the cells and to depicts the tears. Again I used the colors to depict if the bacteria were Gram positive or Gram negative, and used the same types of bacteria first part of the piece. The blue water color paint was dripped down the paper and caused the water color paint I used for the cells to bleed down the paper representing how the bacterial cells are killed by lysozyme in the tears.
Article & Link: A Pregnant Woman’s Diet Could Affect Her Baby’s Gut Bacteria, Study Suggests
Summary: A study was conducted profiling babies gut microbiome. There were some differences between the babies (some were delivered vaginally, some via c-section), which the researchers expected to have the greatest effect of the baby’s microbiome. However the mother’s diet seemed to affect what types of microbes were dominant in the baby’s gut microbiome.
Connections: We were just discussing the human microbiome in class last week, so I thought this article was interesting to read. In class we were talking about why children might have a different gut microbiome than their mothers, and this article did present a case for at least part of the reason why it would differ: the mother’s diet.
Critical Analysis: I found it interesting that this discussed what types of microbes were found in the baby’s gut. The article mentions how women who ate a greater amount of fruit had babies with higher abundance of Streptococcus and Clostridium while women who ate more processed meat had babies with higher abundance of Bifidobacterium. This article seemed to be doing a pretty good job not describing things inaccurately. The person wrote the article interviewed a microbiologist to reassure the audience the bacteria in the babies gut was normal. They also wrote about some of the differences between the babies, such as what percent were delivered vaginally and what percentage were breastfed, and how this could affect the results. Furthermore, the writer also pointed out that the study only took place in New England, and that further research in a wider variety of areas would be important. Another point I found interesting, is that the researchers thought that the delivery method would play a greater role in the baby’s gut microbiome. The one part of the article that was sort of misleading was the headline, because this was about babies that were already born, and seemed to mostly be about the mother’s diet after birth (not during pregnancy). Overall, however, I think this article introduced the idea of the gut microbiome and how the mother’s diet could affect her baby to a general audience pretty clearly and well.
Question: What types of diet should a mother to have for her child to have an ideal gut microbiome?
Sophia Macander – F01
On the EMB plate I decided to draw a floral design with vines surrounding a flower, because I thought it would look nice with the red background. EMB selects for gram negative microbes, so I had to work within those confines. I chose Escherichia coli for the vines, because it strongly ferments lactose, and turns black-green on the EMB plate. For the petals I chose Enderobacter aerogenes, because this microbe does ferment lactose (though not as strongly as E. coli) and would turn pink or red on the plate. Finally, I chose Serratia marcescers for the center of the flower, because it will become colorless due to the fact it doesn’t ferment lactose. It seems like the microbes did what what expected, except for the center, which tuned red instead of colorless. The plate did not change color.
On the MAC plate I drew a sailboat in the water, because I like sailboats. MAC also selects for gram negative bacteria, and the color change is based on lactose 
fermentation. I chose a to use S. marcescens as the boat and sails because it is not a fermenter, and would show up as colorless on the plate due to increasing the pH of the plate. I thought a colorless boat and sails would contrast nicely with the pink color of the plate. I then drew waves with E. coli because it does ferment lactose, and would produce a pink color in the agar. I thought that drawing waves would increase the contrast with the boat. The boat isn’t really colorless in the picture, but a lighter pink, but the surrounding plate is colorless. The E. coli definitely turned a darker pink than the rest of the plate however.
On my TSA plate I drew mountains and the sun, because I love painting landscapes. TSA plates are not differential, because they don’t change color depending on pH (or other) changes. I chose Micrococcus leteus for the sun, because it turns yellow. I then chose Serratia marcescens for the mountains, because I thought red or pink would be a good contrast to the agar color and the yellow M. leteus. When I checked on the plate the mountains had not turned pink yet, but were white (which looked really nice as well). The sun was a bright yellow which looked very nice.
Title: A Rising Threat to Pregnant Women: Syphilis
Summary: Syphilis, which is a sexually transmitted bacterial infection, has been increasing in women (including pregnant women) all over the United States in recent years. This is especially dangerous, because babies that are born with syphilis have a 40% chance of being born stillborn. All pregnant women should be tested for syphilis multiple times during pregnancy, because they can contract it after they are already pregnant. If someone is tested positive, penicillin will be prescribed, and it has a 98% effectiveness rate.
Connections: In the first week of class we talked about the history of discovering microbes, and while this isn’t a discovery, it is important to utilize tests and treatments that were previously discovered so that diseases don’t continue to be spread.
Critical Analysis: While I knew STDs could be passed from mother to child, I hadn’t really thought about how dangerous it could be until I read this article. However, this was a very brief article, so I kind of wish it could have gone into more details about syphilis and how it spread in order to inform the public. I couldn’t find anything intentionally misleading, but its possible some of the statistics were. The only thing that I thought was kind of strange was how they framed the article specifically around pregnant women, and then explained how syphilis has actually just been increasing in women in general. I think this was a short and to the point article that helped inform people that syphilis is dangerous, especially during pregnancy, and that it is importance to get testing and treatment.
Question: This article frames the recent rise in syphilis specifically around pregnant women, even though it is increasing in all women. Was this the article trying to be more sensational, in order to reach more people, and is this a helpful tactic to inform people about dangerous infections? What is the best way to inform people about a bacterial infection that doesn’t initially have obvious symptoms?
Alexandre Yersin is the scientist credited for determining the bacterium responsible for the bubonic plague, Yersinia pestis. Yersin was born in Switzerland and trained to be a physician in Switzerland, Germany and France. In France he trained at the Pasteur institute, and helped create an anti-rabies serum. Eventually he was sent to China and placed in charge of determining the cause of the plague by the French government during an outbreak in Hong Kong in 1894. He successfully isolated and determined the bacteria responsible. A Japanese scientist, Kitasato Shibasaburo, also found the bacteria responsible for the plague at the same time as Yersin. However, Shibasaburo’s method of isolating the bacteria became contaminated, and he also didn’t have the same connections that Yersin did, ultimately causing Yersin to be the scientist credited with discovering the bacteria. Yersin attempted to develop an anti-plague serum, and moved to Nha Trang, Vietnam in order to test the serum. Unfortunately, the serum didn’t work. Yersin then went on to create a medical school in Nha Trang, and stayed in the city until his death in 1943. Yersinia pestis is gram-negative, anaerobic, rod-shaped, and incapable of movement. When Alexandre first discovered the bacterium he named it Pasteurella pestis after the Pasteur institute, but in 1944 it was renamed Yersinia pestis in honor of Alexandre Yersin.
Sources:
“Alexandre Yersin.’ Wikipedia, Wikimedia Foundation, 6 Jan. 2019,https://en.wikipedia.org/wiki/Alexandre_Yersin
“Alexandre Yersin, the Man who Discovered the Bacterium Responsible for the Plague.’ Institut Pasteur, 24 Oct. 2017, https://www.pasteur.fr/en/research-journal/news/alexandre-yersin-man-who-discovered-bacterium-responsible-plague
Butler, T. “Plague History: Yersin’s Discovery of the Causative Bacterium in 1894 Enabled, inthe Subsequent Century, Scientific Progress in Understanding the Disease and theDevelopment of Treatments and Vaccines.’ Clinical Microbiology & Infection, vol. 20,3, Mar. 2014, pp. 202—209. EBSCOhost, doi:10.1111/1469-0691.12540.
“Yersinia Pestis.’ Wikipedia, Wikimedia Foundation, 26 Jan. 2019,en.wikipedia.org/wiki/Yersinia_pestis.
Hello, my name is Sophia and I am a second year biochemistry student. I’m planning on going to pharmacy school after I finish my bachelor’s degree. I enjoy reading, painting, and hiking. I’m very excited to learn more microbes!