(Changes virus in secong paragraph to bacteria)
By Julie Steenhuysen
CHICAGO, June 20 It is a Friday the 13th Dr Paul
Meechan will not soon forget.
On that night last week, bioterrorism researchers at the
U.S. Centers for Disease Control and Prevention (CDC) discovered
they had mistakenly sent live anthrax bacteria out to fellow
scientists in two lower-security clearance labs at the agency,
instead of what they thought were harmless samples of the deadly
The initial safety lapse occurred in the CDC's Bioterror
Rapid Response and Advanced Technology laboratory, a high
security lab that was trying out a new protocol for inactivating
anthrax, using chemicals instead of radiation.
In an interview, the CDC's Meechan described some of the
events that led to the discovery that as many as 75 agency staff
had been exposed to live anthrax. The CDC first disclosed the
incident to Reuters on Thursday.
The scientists in the Bioterror Rapid Response units had
been preparing an especially dangerous strain of the bacteria
for use in two lower-security CDC labs, the Biotechnology Core
Facility and the Special Bacteriology Reference Laboratory,
Those teams were experimenting with methods to more quickly
identify anthrax in substances and powders sent to the United
"If there was a bioterrorism incident, we could more quickly
identify yes or no, this sample has anthrax," said Meechan,
director of the CDC's environmental health and safety compliance
Meechan said the team in the bioterror lab used a new
process to purify anthrax samples that they had not had a lot of
experience with. To check their work, they took a sample of what
they thought was dead bacteria and put it on a nutrient-rich lab
dish called an agar plate to see if the bacteria would grow.
"They waited 24 hours. They took a look at the plate and
they didn't see any new growth," Meechan said. "At that point
they assumed the material was safe."
NO ILLNESS REPORTED
Researchers took the slides to the two lower-security CDC
labs which were trying to develop the new tests. Their
experiments did not work and a week later, one of the labs asked
for additional inactivated samples.
At the time, researchers in the bioterror lab discovered
that they had left the agar plates in an incubator for an
additional week, Meechan said.
As they were about to dispose of them, they noticed growth
on one of the agar plates. "The growth turned out to be
anthrax," he said.
That is when the scientists realized the samples they sent
to the two lower-security labs may have contained live anthrax
bacteria. People working in those labs take fewer safety
precautions and were unlikely to be wearing a respirator,
putting them at higher risk for infection.
Meechan said the team immediately pulled back the
samples and contacted the staff members who had handled them.
That was on the evening of Friday, June 13th.
Meechan said they reached some of the lab workers that same
night. Since then, they have been interviewing managers and
using electronic surveillance and key card data to identify
anyone who might have been inside one of the two labs testing
The CDC has reached out to all identified individuals, who
have been offered antibiotics and a vaccine.
No instances of illness have been reported.
(Editing by Michele Gershberg and Robert Birsel)