CDC admits to poor lab safety measures

Lax safety measures in labs could lead
to staff exposure to dangerous microbes.

Dr. Thomas R. Frieden, the head of the Centers for Disease Control and Prevention, spent much time completing a report that would let the public see how the sloppy handling of anthrax by scientists at its headquarters had potentially exposed dozens of employees to the deadly bacteria.

But then he got a call about another accident, this one just as disturbing, if not more so — and no one in the agency’s top leadership had been informed about it earlier, though the C.D.C.’s lab had been told about it more than a month before.

C.D.C. workers had somehow shipped a dangerous strain of avian influenza to a poultry research lab run by the Department of Agriculture. Known as H5N1, the virus had killed more than half of the 650 people who had been infected with it since 2003.

The recent revelations have created a crisis of faith in the federal agency, prompting calls for an independent body to investigate such episodes in the future, as well as for sweeping changes at the agency and to a sprawling web of research labs that has grown after the 2001 terror attacks led to an intensified focus on microbes that could be used as biological weapons.

Dr. Michael Bell, a 19-year C.D.C. veteran who has been appointed by Dr. Frieden to a new position overseeing laboratory safety, said in an interview that he was most concerned about the “potential for hubris” among researchers who grow so inured to the daily grind of working with deadly microbes that they cease to follow safety protocols.

The agency both conducts that research and is charged with ensuring that other labs adhere to federal safety standards.

The agency’s internal investigation of the troubling events found that senior staff members had failed to write up a plan for researchers to follow in the anthrax study.

It also faulted scientists who neglected to review the existing literature before working with the deadly pathogen, and found that the agency was ill-prepared to respond to a potential exposure episode.

“It is ironic that the institution that sets U.S. standards for safety and security of work with human pathogens fails to meet its own standards,” Richard H. Ebright, a professor of chemistry and chemical biology at Rutgers University, wrote in an email . “It is clear that the C.D.C. cannot be relied upon to police its own select-agent labs.”

Dr. Frieden has closed the agency’s flu and bioterror laboratories and has banned all shipments from the agency’s highest-security labs while safety protocols are reviewed — a move that could freeze work at many public-health labs that rely on such shipments

Later this month, the C.D.C. will invite outside experts to form an external advisory group on lab safety. But some experts say that the agency should not police itself.

Dr. Frieden said the idea of an independent investigative agency was “certainly worth exploring.”

The anthrax accident occurred on June 5 in the agency’s bioterrorism rapid response lab. C.D.C. researchers in Atlanta had been preparing to test a faster way to identify dangerous substances. The lab used a virulent anthrax strain in the test when a weaker one would have worked.

The work was conducted in area classified as a “three” on the biosafety scale, with four being the highest security level. Such labs work with microorganisms that may lead to serious illness or death if inhaled, and follow strict safety guidelines: Workers wear safety hoods that filter air and typically work with infectious materials in special ventilated boxes called biosafety cabinets.

On June 2, according to the report, a lab supervisor called a scientist at another lab who had done similar work on a different bacterium, brucella, which can cause fevers and swelling in humans.

The written protocol for preparing brucella for the test was sent to the bioterrorism lab, and the supervisor told a scientist to follow it while preparing eight dangerous pathogens, including anthrax. But anthrax forms hardy spores, while brucella does not.

In addition, the brucella protocol required that bacteria be killed in a bath of formic acid for 10 minutes, and that small samples of it be incubated for 48 hours to be sure it was dead.

But a mix-up occurred when the instructions were conveyed over the phone. The scientist incubated the test samples for only 24 hours before sending the bulk of the bacteria to less-secure labs. Some of the bacteria were not filtered to remove spores.

After 24 hours, one scientist tried to sterilize the test plates in a high-power steam autoclave. But its door was stuck, so the plates were returned to the incubator. It was an inconvenience that would prove extremely lucky.

Over the next few days, scientists in two other labs where breathing equipment was not used agitated the bacteria and sprayed them with compressed gas, which could have blown spores into the air.

On June 13, one scientist checked the incubated plates and saw that anthrax was growing. If the door to the autoclave had opened properly and, as the report noted, the plates had been sterilized, “the event would not have been discovered.”

The troubling finding was reported immediately, according to the report. Rooms were closed off, and floors, tabletops, equipment and door handles were decontaminated.

Lab tests would later determine that the chemical bath would have killed any live, growing anthrax sent out of the lab, but not all the dangerous spores. Staff exposure, the report concluded, was “not impossible,” but “extremely unlikely.”

By looking at videotapes and the use of door key cards, managers tried to figure out who might have been exposed. They discovered another safety violation: staffers often “piggybacked,” following colleagues through doors without using their own cards.

Ultimately, 62 employees were offered vaccines and antibiotics. None have shown signs of illness related to anthrax exposure.

The near miss should have been reported immediately to top leadership, but was not.

Dr. Frieden said the delay shocked him because the agency’s flu lab is renowned in its field.

The report recalled other errors. In 2006, the agency accidentally sent live anthrax to two other labs, and also shipped out live botulism bacteria.

Both Dr. Frieden and his predecessor, Dr. Julie L. Gerberding, replied in letters over their signatures that the problems would be fixed.

The agency’s report suggested that fewer labs should be handling dangerous microbes.

Source: New York Times
This article has been edited for length.

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