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St. Luke's invests in machine that speeds up identification of infection-causing bacteria, fungi

The newly purchased technology can't be used to identify viruses such as coronavirus.

Jennifer Berglund, a microbiology technician specialist at St. Lukes, places a target that can hold up to 97 samples, into the hospital’s new Bruker MALDI Biotyper. Using laser and a mass spectrometry the device can identify bacteria and fungus infections within minutes. (Steve Kuchera / skuchera@duluthnews.com)

St. Luke's hospital has invested in a $250,000 machine that can identify bacteria or fungi causing an infection in patients much quicker and on-campus.

"We used to do this and still do this through a lot of biochemical testing that takes hours or days to figure out what the identification is," said St. Luke's infectious-disease physician Dr. Andrew Thompson. "(The new machine) allows us to identify things more quickly and when we can do that we know exactly what bacteria or fungus is causing an infection, and then we can target with antibiotics or anti-fungal medication right away depending on what the pathogen is."

Oftentimes, St. Luke's will even send samples to the Mayo Clinic in Rochester, further lengthening the amount of time it can take before patients can receive the specific treatment they need.

The new system, called a MALDI, for matrix-assisted laser desorption ionization time-of-flight mass spectrometry, uses lasers to zap the microbes, Thompson said. During that process a "fingerprint" of the molecules is created and then matched against a database of several hundred known organisms.


Dr. Andrew Thompson of St. Luke's Infectious Disease Associates talks about the hospital’s new biotyper. (Steve Kuchera / skuchera@duluthnews.com)

The biotyper is still undergoing testing at St. Luke's before it's used clinically to identify microorganisms in patients, though it has been in use worldwide for over a decade. St. Luke's is the first health care system in the region to use the technology.

Not only did the technology that preceded the new machine take longer to identify fungi or bacteria, it also was less cost effective, Thompson said, costing a couple dollars per test, whereas a test costs about a couple cents on the biotyper.

Thompson emphasized that the sooner health care professionals know what's causing an infection, the sooner they can get patients on the proper medication.

"If someone comes in pretty sick, we'll put them on probably two antibiotics, sometimes three, really broad treatment," Thompson said. "Currently, we have to continue that for a couple days until we identify bacteria and then after that what's going to work against it."

Jennifer Berglund holds the small target that holds up to 97 samples for the new biotyper to analyze. (Steve Kuchera / skuchera@duluthnews.com)

The more broad-spectrum antibiotics are used, the more humans develop resistance to those treatments, which is something health care professionals want to avoid, Thompson said.


"That speed at which we can identify things allows us to focus and target that much more quickly," he said, adding that the sooner health care professionals know what treatments are needed, the less patients need to spend on broad-spectrum treatments.

That's especially true with fungal infections since some of the newer anti-fungal treatments are more expensive.

The newly purchased technology can't be used to identify viruses, Thompson said. While it can in theory identify viruses like the one that causes COVID-19, it would need to be grown in culture first, a process that takes time and wouldn't be faster than the current tests used to diagnose people with COVID-19.

Microbiology technical specialist Jennifer Berglund said the machine has a 97% sensitivity rate ⁠— or accuracy rate ⁠— and called it the "gold standard."

Progress of scanning samples is displayed on a computer monitor. (Steve Kuchera / skuchera@duluthnews.com)

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