The Centers for Disease Control and Prevention (CDC) has reported that 75 Atlanta-based staff may have been unintentionally exposed to live Bacillus anthracis, the cause of the anthrax disease, and are being monitored or provided antibiotics to prevent infection.
According to CDC, the staff may have been unintentionally exposed to Bacillus anthracis after they failed to follow established safety practices.
The CDC found the potential exposure on 13 June when the original bacterial plates were collected for disposal and Bacillus anthracis colonies (live bacteria) were found on the plates.
At the time samples were distributed to the other CDC laboratories, these plates had appeared negative for the bacteria.
The agency immediately began contacting individuals working in the labs who may have unknowingly handled live anthrax bacteria.
CDC said that based on most of the potential exposure scenarios, the risk of infection is very low.
Early reports showed that one of the CDC’s Roybal campus biosafety level 3 labs was preparing Bacillus anthracis samples for research in other CDC labs at lower biosafety levels to yield new means of detecting dangerous pathogens in environmental samples.
However, the lab used a procedure that did not adequately inactivate the samples and these potentially infectious samples were moved and used for experimentation in three CDC Roybal campus laboratories not equipped to handle live bacteria.
Believing the samples were inactivated, workers in those labs did not wear adequate personal protective equipment while handling the material.
Lab safety investigators also determined that, sometime between 6 June and 13 June, procedures used in two of the three labs may have aerosolised the spores.
Image: Photomicrograph of a gram stain of Bacillus anthracis. Photo: courtesy of Centers for Disease Control and Prevention.