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Measuring antibiotic resistance among E. coli

9:00AM, August 8, 2018
Doing Science

Chidera found that E. coli developed a complete resistance against Erythromycin in her study.

Antibiotic resistance is a serious issue facing both medical providers and patients.

According to the World Health Organization, a growing number of infections, such as pneumonia, tuberculosis, gonorrhea, and salmonella, are becoming harder to treat as the antibiotics used to treat them become less effective. Antibiotic resistance can lead to longer hospital stays, higher medical costs, and even increased mortality. This resistance increases as more people overuse antibiotics.

“This can lead to illnesses that were previously treated with antibiotics developing resistance, making it harder for people to overcome the illness,” said Chidera Obiwuma, a student at Benjamin Banneker Academic High School in Washington, D.C. “It can even manifest into something life-threatening."

When bacteria become resistant to the antibiotics we use when we get sick, this threatens our ability to be able to rely on antibiotics as a means of fighting off illnesses, especially when a person’s immune system cannot fight the bacteria off itself.

"Because we treat our livestock with antibiotics, they can develop gut-resistant bacteria," Chidera explained. "When we eat them we can also get the resistant bacteria in our gut.”

Chidera researched antibiotic resistance among E. coli.

Chidera tested four different antibiotics on E. coli over two generations, to see if the bacteria developed any resistance. She first learned about antibiotic resistance in International Baccalaureate (IB) biology. “This made me want to test how strong commonly used antibiotics were against E. coli,” she said.

She tested if E. coli developed resistance against Tetracycline, Erythromycin, Neomycin, and Streptomycin. Chidera tested two strains with no ampicillin resistance as well as one with ampicillin resistance. Ampicillin resistance means that specific strains of E. coli have developed resistance toward the antibiotic Ampicillin.

After growing bacteria in Petri dishes, she treated them with antibiotics and then measured the length of the zones of inhibition formed by each antibiotic. Zones of inhibition are areas where bacteria haven't grown and where an antibiotic stopped the bacteria from growing or killed it.

Based on the data, Tetracycline and Neomycin were the most effective against two generations of E. coli. She noted that E. coli developed a complete resistance against Erythromycin in her study.

“The project proved that E. coli did become resistant to certain antibiotics over the two generations, but at different degrees,” Chidera explained. “None of the four antibiotics were able to completely fight off the strains of bacteria.”

Her research was selected by her local science fair for recognition as a Society for Science & the Public Community Innovation Award winner. This award honors students participating in science fairs around the world who are making a difference in their communities. In 2018, the Society rewarded 20 young scientists with $500 prizes — and Chidera was one of them.

“This award is fulfilling,” Chidera said. “It encourages me to pursue science and shows me the potential impact my project could have on the lives of people."

Chidera believes that science fairs help students go beyond the classroom. “They foster the idea of developing independence and thinking critically,” she said. “After the science fair, I developed a newfound confidence and try not to limit myself in terms of how I pursue science.”

In college, Chidera plans to study biology and enter a premedical track. Her mom, a nurse, inspired her to enter the medical field and aspire to become a surgeon. She recently received a full-ride scholarship to George Washington University and will attend in the fall.

What is her advice for others interested in pursuing STEM? “Stay open-minded and explore different things,” Chidera said. “You never know where your next idea or inspiration can come from.”


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