Risk Assessment for Enteric Pathogens in the Biosafety Level 2 Laboratory

Abstract

There is some general confusion regarding when to use a biological safety cabinet (BSC) to minimize risk from aerosol formation in Biosafety Level 2 (BSL'2) laboratories that handle enteric pathogens. A risk assessment was conducted to determine the risk involved in performing some standard microbiological manipulations. Although enteric organisms are not known to be infectious via inhalation, it was felt ingestion of droplets deposited around the work area may cause laboratory-acquired infection. Manipulations of Salmonella spp., Shigella spp., Escherichia coli 0157, and other E. coli have resulted in laboratory-acquired infection due to improper laboratory technique. Routine procedures, for example opening screw-capped bottles and wet petri dish covers, improper use of needle and septum, streaking plates, pipetting, slide agglutination, and microscopic preparations, were found to have potential to cause aerosol formation. Proper microbiological technique in combination with primary containment devices (e.g., biological safety cabinets) has been found to reduce the risk of laboratory-acquired infections when working with enteric pathogens. Laboratory workers must ensure that they use any means available to minimize these risks.