Dr. David Cummings, professor of biology, listened as one of his students, Jenna, told him that she found the CTX-M gene in the Tijuana River Estuary. Cummings and his students have found many types of DNA in this estuary, but this one is different.
Finding CTX-M, a high-level drug resistance gene found in some bacteria, is crucial because it had never been seen outside a hospital setting. That is until Jenna had the opportunity to do field research with Cummings and found it. Since CTX-M makes bacteria resistant to antibiotics like penicillin, it’s dangerous DNA.
“This gene has been plaguing hospitals for years,” said Cummings. “So it’s amazing that we found it in the estuary…it’s definitely something we will be researching further.”
Why is Cummings concerned with DNA and not just the bacteria?
“Bacteria have this strange ability to swap DNA with each other,” said Cummings.
That makes the DNA itself a pollutant because it may get picked up by other strains that can survive the high salinity and light exposure in our coastal wetlands and then find its way back into the community.
Making discoveries that impact human health is something Cummings says he could not do without his students.
“My students are vital. The vast majority of data collection is from them. They are truly the hands of the work I do,” he said.
Cummings has been working with sediments in order to find many types of antibiotic-resistant bacterial DNA in Southern California wetlands. He and his students make trips to the Tijuana River Estuary, Famosa Slough in Point Loma, and Ballona Creek Estuary near the Los Angeles International Airport. The team gathers samples of sediment at low tide, mixes and freezes the samples, and then separates the DNA to find important DNA sequences.
It was only a few years ago that drug resistance genes were discovered washing into our wetlands, so Cummings and his students are collecting critical data.
“We are really the only lab looking at drug resistance genes along coastal urban areas,” said Cummings.
In all three of the urban estuaries they are studying, they have found bacterial DNA encoding that is resistant to some of the most widely prescribed antibiotics, including tetracycline, which is used to fight bacterial infections like pneumonia and other respiratory tract infections.
“This is a problem because the resistance of bacteria seems to be slowly but surely outpacing the development of drugs,” said Cummings.
As Cummings continues to study the genes of these bacteria, he hopes to find answers to some of these problems, one strand of DNA at a time.
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Professor Dave Cummings' research was featured in PLNU's 2009-2010 Annual Report. You can download the complete report and learn about more university achievements.