What is Biosafety?
WHAT IS BIOSAFETY?
Biosafety is defined as, “The discipline addressing the safe handling and containment of infectious microorganisms and hazardous biological materials” (1). The practice of safe handling of pathogenic micro-organisms and their toxins in the biological laboratory is accomplished through the application of containment principles and the risk assessment.
Safety in the laboratory is achieved by application of layered, containment principles applied in accordance with the risk assessment to prevent exposure of laboratory workers to a pathogen or the inadvertent escape of a pathogen from the microbiological laboratory.
Safety layers include primary and secondary containment. Primary containment provides immediate protection to workers in the biological laboratory from exposure to chemical and biological hazards. Primary barriers include biological safety cabinets, fume hoods and other engineering devices used by laboratory technicians while working with a biological hazard. Secondary containment is intended to protect the laboratory worker, the community and the environment from unintended contamination with a biological hazard. Secondary containment consists of architectural and mechanical design elements of a facility that prevent worker contamination and escape of pathogens from the laboratory into the environment. Personal protective equipment (PPE) such as gloves, laboratory coats and safety glasses may also be considered a primary containment, however, articles worn on the body are considered a last line of defense and are only used in conjunction with other primary and secondary containment elements when working with pathogenic organisms.
Containment is defined in levels that increase in complexity as the risk associated with the work in the microbiological laboratory increases. All containment levels have defined primary and secondary containment features. These levels are described by a series of working practices, applied technologies and facility design built upon from a common foundation, referred to as biosafety level -1 or BSL-1. In the U. S. there are four containment or biosafety levels; BSL-1 - BSL-4. The criteria for each level are described by the CDC and NIH (1, 2).
One important biosafety element suggested for all 4 biosafety levels is biosafety training. Provision of basic training in biosafety is considered a best practice and is usually provided by the Biosafety Officer or Occupational Health Specialist to visitors, students and workers in biological laboratories. Specialized training is also required by the Occupational Safety and Health Administration (OSHA) for work that has the potential to expose laboratory employees to human blood or human blood products and for procedures that require the use of a respirator (3, 4). Scientists working biological laboratories are often required to demonstrate competency at BSL-2 before working in a BSL-3 laboratory and competency and reliability are required for work in a BSL-4 high containment facility. As competency training is laboratory and project specific, the lead scientist or principal investigator has responsibility to work with the biosafety officer; integrating biosafety and biosecurity into laboratory procedures and assuring competency training of the laboratory staff.
BIOLOGICAL RISK AND THE RISK ASSESSMENT
The biological risk assessment for a microbiological or biomedical laboratory is determined by assessing the hazards posed by the biological agent and the risks of associated laboratory activities. A Hazard Analysis is used to determine the hazard attributed to the biological agent. Pathogen hazards are categorized into four Risk Groups (RG) of ascending risk (RG1-RG4). The risk group of a biological agent is determined using three criteria: Pathogenicity, or the ability to cause disease in humans or animals; Availability of medical countermeasure or prophylactic treatment for the associated infection; and, Ability of the disease to spread. Pathogenicity is most often associated with the number of organisms required for infection (assessed in colony forming units or CFU) with bacteria that require a low number of CFU for infection considered to be more pathogenic. Coxiella burnetti and Francisella tularensis are considered highly pathogenic organism because they have been reported be infective with 10 or fewer bacilli as compared to 103 bacilli for non-typhoidal Salmonella5. Medical countermeasures include vaccines and antibiotics or anti-viral medications that are effective preventative or treatments for disease. The ability of an infectious disease to spread is determined by the route of infection with pathogens transmitted by aerosols considered more hazardous than other types of transmission; due to the potential for multiple exposures to occur in a single incident.
The risk assessment also considers all aspects of the laboratory space that can increase the risk of exposure to a pathogen. Laboratory activities and facility design faults that are known to have caused Laboratory Acquired Infections (LAIs) are included in the overall risk assessment as well as elements of the safety program, such as training or containment features that reduce the associated risk. Because the assessment of risk is particular to the organism, the laboratory program and design features, the risk assessment must be made for each laboratory and risk must be re-assessed when protocol or personnel changes are made.
In the Risk Assessment, risks are commonly categorized according to likelihood and consequence and are visualized in a continuum from low likelihood/low consequence - high likelihood/ high consequence- risks. As it is impossible to eliminate all risks, this type of analysis allows stakeholders to determine the level of risk that is acceptable and to focus risk mitigation efforts to higher-risk activities.
The History of Biosafety and ChABSA
In the mid- to late 1800’s, the science of microbiology had advanced to the point that the causative bacterial agent of common diseases such as tuberculosis, diphtheria and cholera were identified using Koch’s postulates. Following close behind this initial work in the culture and purification of bacterial pathogens, LAIs were first reported. In the early- to mid-1900’s, wooden and steel boxes were designed to prevent work-related LAIs, however it took many more years for the discipline of biosafety to develop. Biological Safety was pioneered at the U. S. Army Biological Research Laboratories in Fort Detrick Maryland led by the efforts of Arnold G. Wedum, Director of Industrial Health and Safety and the father of modern biological safety. Dr. Wedum was one of the original pioneers of the first Biological Safety Conference and was central in the formation of the American Biological Safety Association (ABSA). Today ABSA is an international organization (ABSA International) serving 37 countries with 1232 members (http://absa.org/about.html). ChABSA is a local chapter of ABSA serving the Maryland, Virginia and Washington DC areas and dedicated to expanding biological safety awareness (http://www.chabsa.org/index.php?option=com_content&view=article&id=2&Itemid=138).