Showering BSL-4 Suits to Remove Biological Contamination

Positive pressure suits are widely used at BSL-4 to protect operators from contact with microbiological agents. As there is the potential for the outside of the suits to become contaminated during use, they must be decontaminated prior to final exit from the high-containment laboratory. Chemical showers are used to remove biological material from suits, and the shower effluent is collected for subsequent treatment by heat or chemicals. The efficacy of showering to clean/remove biological materials from two different BSL-4 suits (ILC Dover and Delta) was studied using Bacillus atrophaeus spores dried directly onto the suit surface as a surrogate contaminant, with a 4 log colony forming unit (cfu) reduction pass criterion required. Initial studies using water alone, without disinfectant, achieved a 1–2 log cfu reduction in the microbial contamination. However, direct scrubbing, using a lightweight brush combined with relatively short cycle times (6 minutes) and low water volumes (<45 L per cycle) achieved a...