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UPDATED: University of Chicago Microbiologist Infected From Possible Lab Accident

Another laboratory-acquired infection may have occurred in a University of Chicago building where 2 years ago a researcher contracted plague and later died. Late last month, a researcher who worked in the same general lab area was hospitalized with a skin infection caused by a common bacterium being studied in her lab.

The researcher became infected with Bacillus cereus, which can cause food-borne infections, while working on a project headed by microbiologist Olaf Schneewind, according to the university. She was hospitalized on 27 August; after receiving surgery and antibiotics, she was released. In her lab, where B. cereus was studied in biosafety-level 2 conditions (on the lower end of four biosafety levels), the university suspended research to decontaminate the area as a precautionary measure (it was expected to open later this week).

The researcher was likely exposed through an open wound. The university is still investigating whether she acquired the infection in the lab, said University of Chicago Medical Center spokesperson Lorna Wong. B. cereus is not contagious as long as standard procedures such as good hand-washing hygiene are followed, but family members and co-workers were screened for infection risk and some were offered precautionary antibiotics.

Two years ago, a researcher who worked in the same area in the Cummings Life Science Center, geneticist Malcolm Casadaban, a co-principal investigator with Schneewind, died after becoming infected with a weakened strain of the Yersinia pestis bacterium that was not thought to infect healthy adults. According to a report in the Centers for Disease Control and Prevention's Mortality and Morbidity Weekly Report, Casadaban may have become sick because he had hemochromatosis, or an overload of iron in the body. The Y. pestis strain had been weakened by making it less able to acquire iron, and the excess iron in Casadaban's body might have allowed it to be become more virulent, the MMWR report says.

That report said Casadaban, who was known to use gloves inconsistently, may have become infected through dermal exposure—possibly the same exposure route as the researcher infected with B. cereus. The university said that Chicago's public health department has visited the campus and reviewed the lab's safety procedures.

Neither case involved a select agent—a pathogen on CDC's list of potential agents in a biological attack. (Although Y. pestis is on the list, the strain Casadaban studied was excluded.) But Schneewind also directs the Great Lakes Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research, a consortium funded by the National Institute of Allergy and Infectious Diseases (NIAID) to study select agents and natural threats. The center does some of its work at a major biosafety level-3 lab on the campus of Argonne National Laboratory, one of a dozen such regional biocontainment labs built partly with NIAID funding after the 2001 anthrax attacks.

Schneewind did not respond to an e-mail this morning seeking comment.

Updated on 13 September: Today ScienceInsider discussed the incident with Conrad Gilliam, University of Chicago dean for research and graduate education in the biological sciences division. Gilliam said that Olaf Schneewind's group was studying B. cereus in a BSL-2 facility using BSL-3 practices, such as a biosafety cabinet, as a precaution. The infected researcher wasn't working on B. cereus but may have touched her gloved hand to a drop of inoculant spilled by another researcher, then touched a wound on her skin that wasn't properly covered, Gilliam said. The university is having B. cereus samples sequenced to verify that the strain she was infected with was acquired in the lab.

The university is concerned that the B. cereus accident follows the 2009 plague infection, Gilliam said. "The fact that there have been two serious incidents [involving] individuals, we take that very seriously. It doesn't matter if it was a statistical fluke or not." As a precaution during the decontamination and university's inquiry, Schneewind is moving work on B. cereus and some other BSL-2 pathogens that his team had been studying using BSL-3 practices from the Cummings building to the off-campus Ricketts BSL-3 facility.

Once the move and decontamination of Cummings labs are complete, "We'll seriously sit down to retraining, retooling, rethinking" biosafety procedures, Gilliam says. He added that he is responding to queries about the incident so that Schneewind can focus on moving four researchers and their projects to the off-site lab.