UNLV research helps scientists track down anthrax

Friday, Nov. 2, 2001 | 11:22 a.m.

A decade ago researchers at the University of Nevada, Las Vegas saw a need for a new, reliable test to identify bacteria in the air.

Today, investigators are using their findings to identify potentially deadly anthrax spores in post offices and federal buildings on the East Coast.

The UNLV research team included Linda Stetzenbach, director of the microbiology division at the school's Harry Reid Center for Environmental Sciences.

The technology that the group developed essentially collects genetic material from microscopic bacteria cells floating in the air, then reproduces the genetic material, Stetzenbach explained. Computers then compare the gene sequences of the material to previously identified sequences from bacteria.

Since the gene sequences for different bacteria are unique to a single species, a match provides a very reliable way to identify an organism in the air.

UNLV researchers wrote a paper in 1993 outlining the technology and the reason it could be used in situations in which airborne bacteria are suspected.

"Use of Solid-Phase Polymerase Chain Reaction for Enhanced Detection of Airborne Microorganisms" was published in the journal of Applied and Environmental Microbiology the next year.

The paper said the technology could be used to collect and identify samples from a number of airborne bacteria, including the organism that causes Legionnaires' disease. Anthrax wasn't mentioned in the paper.

Stetzenbach said the technology developed at UNLV has some advantages over older methods of identifying organisms in the air. Traditionally, scientists collect a sample, transfer it to a growth medium in a petri dish, then wait days or even weeks for the organism to grow.

The scientist then looks at the result through a microscope. Hopefully, the scientist will be able to recognize the bug.

The new technology doesn't have to go through those steps or depend on the subjective reaction of the investigator, Stetzenbach said.

"It's fast, much quicker and much more reliable," she said. "It can get you answers within a couple of hours as opposed to days or weeks with cultures. You can process a lot more samples at one time.

"It's a crisp, very objective test," she said.

The technology isn't infallible. Although a positive result is usually conclusive, the tests can give "false negatives," Stetzenbach said. The test works well when investigators are looking for a known organism and can minimize interference from other organisms.

The research was funded by the National Science Foundation and the Environmental Protection Agency.

Donna Garland, a spokeswoman with the Centers for Disease Control and Prevention's investigation effort in Washington, confirmed that the investigators on the East Coast are using the technology to identify anthrax spores. It is one of various testing methods in their arsenal, including traditional culturing of airborne samples.

"It gives scientists another way to assay for contaminants in the air, whether they are there purposefully because of bioterrorists or by Mother Nature," Stetzenbach said.

Stetzenbach said researchers didn't know in the early 1990s that their work would aid investigators of a bioterror attack. That isn't unusual in the world of science, she said.

"You don't always know how the research you do will be applied," she said. "You just have to apply good techniques and answer questions today with an eye on the future."

The techniques refined at the Harry Reid Center have another practical application that is the focus of research today, Stetzenbach said. Researchers are now using it to identify airborne fungi, a growing health problem in commercial and residential buildings.

One of the center's researchers, Patricia Cruz, has applied for two patents for the detection of fungi contaminating indoor air.

"We have a wonderful group of experienced and intelligent research scientists at the center," Stetzenbach said, including three with doctorates, graduate students and undergraduates.

All of the center's microbiology work is funded by grants and contracts, she said.

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