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Antibiotic-Resistant Aeromonas in the North Channel Chicago River

City, Chicago, Skyline, DowntownWith the sweltering, hot summer in the middle of July, there are children and adults who are running into the waters looking for a refreshing way to cool down especially in the city of Chicago. However, before we dive right in, there is a peculiar thing in those waters. No, it is not a rubber ducky nor is it a glistening pebble, but rather, it is the growth of an antibiotic-resistant batch of bacteria.

I conducted this scientific research in a microbiology and genome course at North Park University with the Provost Scholarship. With the guidance of Dr. Drew A Rholl, the professor who helped lead the exploration, we were able to focus on the question of whether there are any unknown bacteria present in the waters of Chicago. The purpose of the experiment was to isolate, inspect, and identify the viable bacteria in the Chicago River’s North Channel water supply. By doing so, we were able to understand the current state of our waters and explain its potential effects on human beings and the ecosystem.

To begin, we created colonies and amplified the number of viable bacteria by dilution and membrane filtration with multiple nutrient agar. After growing the dilution plates in the incubator, we were able to subculture individual colonies and investigate them from the nutrient agar plus ampicillin 10^1 dish.  By utilizing the nutrient agar plus ampicillin, we would be able to find out if there are any bacteria that may be resistant to ampicillin, an antibiotic that helps treat many bacterial infections. Interestingly enough, there were many viable colonies that grew from the plate. We had an antibiotic resistant bacteria amid our waters.

After this discovery, we began to focus on the macroscopic analysis of the unknown bacteria by incorporating gram staining, which helped us understand its phenotypic characteristics. Through the microscope, we saw a clustered gram-negative bacteria that had a rod-shaped morphology. To improve our investigation, we also introduced biochemical tests with blood agar, oxidase, and catalase. The tests helped confirm that the bacteria had a positive reaction with the oxidase, gamma for blood agar, and positive for the catalase.

However, with a myriad of bacteria that may all share the same characteristics, we needed a definitive answer. With the help of genetic testing, we were able to identify the bacteria to some extent.  We utilized polymerase chain reaction (PCR) and gel electrophoresis to amplify as well as purify the DNA before sending it off to a sequencing center. After receiving the query results, we inserted the DNA into BLAST. The database authenticated that the bacteria was in the genus Aeromonas with a possible strain of veronii, media, sobria, caviae, or hydrophila.

Conclusively, we discovered that there is a major growth of possibly harmful, antibiotic-resistant bacteria in the North Channel site. According to Kenyon College, Aeromonas is pathogenic to humans as it causes gastroenteritis and forearm infection. Furthermore, the National Institute of Health reveals that Aeromonas can have a serious effect on immunocompromised individuals. However, Aeromonas also does much more especially to our ecosystem, specifically fish. The bacteria can cause scale protrusion and fin rot, problems that are detrimental to the health of fish (Kenyon College).

While considering the effects of this antibiotic resistant bacteria in our waters, we must propose future work. We must investigate more testing on Aeromonas in order to determine the specific strain and how it may contribute to the infamous phenomena of many bacteria becoming resistant to our antibiotics. Additionally, because North Channel is a sewage site at the Chicago River, there must be a further inquiry on any ecological damage in the water. Although from another perspective, there may actually be possible benefits in having Aeromonas in our waters. A great research project would be testing other waters outside of Chicago from various states where water is in great abundance.

Nevertheless, with this project, I learned about how there need to be major renovations and efficient cleansing in the Chicago River. Water quality is a serious issue in the world today. We must ensure that its state is safe for consumption and usage in order to maintain our health. Furthermore, if there are pathogens in our water, the sustainability of our environment is at risk here. Thus, before jumping in, make sure that you know the water is safe.


Works Cited

“Aeromonas.” Microbewiki. Kenyon College, 14 Oct. 2014. Web. 07 July 2016. <>.

Janda, J. Michael, and Sharon L. Abbott. “The Genus Aeromonas: Taxonomy, Pathogenicity, and Infection.” Clinical Microbiology Reviews. American Society for Microbiology (ASM), Jan. 2010. Web. 07 July 2016. <>.

Editor: Olivia Vo