Laboratory Biosafety Levels
Goals • Define barriers and procedures used by laboratories to protect workers and others from infection • Describe the four biosafety levels and the protective measures used by each type of laboratory when handling infectious materials • Provide examples of the types of biological agents handled in each type of laboratory • Describe typical places where each type of laboratory can be found in the US
Why is Biosafety Important? • Laboratorians recognize hazards of processing infectious agents • Guidelines developed to protect workers in microbiological and medical labs through engineering controls, management policies, work practices
Biosafety Levels • Precautions so people researching or trying to identify organisms do not become infected • While handling or testing clinical specimens, workers could accidentally infect themselves or coworkers • Labs must adhere to very specific safety regulations to work with organisms that pose a threat to human health
Biosafety Levels • Regulations outline precautions, special practices, decontamination procedures • Labs divided into 4 biosafety levels; protective practices increase with each • Biosafety Level 1 labs - work with least dangerous agents, require fewest precautions • Biosafety Level 4 labs - have strictest methods because dealing with agents that are most dangerous to human health
About this Information… • Information summarized here should not be used to establish laboratory safety protocols • Complete information and recommendations can be found in Biosafety in Microbiological and Biomedical Laboratories 5th Edition at http://www.cdc.gov/od/ohs/biosfty/bmbl4/ bmbl4s6.htm
Barriers • Primary barriers: physical barriers or personal protective equipment between lab worker and pathogen • Gloves, masks, special breathing apparatuses • Secondary barriers: structural aspects of the laboratory that make working environment safer against infection • Sinks for handwashing, special containment areas, special air ventilation patterns
Universal Precautions • Universal precautions developed to protect health professionals • Most often apply in a clinical setting • May also be important for field epidemiology practices during an outbreak investigation (e.g., collecting lab specimens) • Include hand hygiene, gloves, gown, masks, eye protection, face shields, safe injection practices • Require that all equipment or contaminated items are handled to prevent transmission of infectious agents • Special circumstances may require additional precautions • Protective clothing, special site decontamination
Biosafety Level 1 (BSL-1) • Agents not known to cause disease in healthy adults • Some organisms may cause disease in immunocompromised individuals • Agents include Bacillus subtilis, Naegleria gruberi, infectious canine hepatitis virus, non-pathogenic E. coli species (transmission electron micrograph of E. coli)
Biosafety Level 1 (BSL-1) • Standard practices required: • frequent handwashing • door that can be kept closed when working; • limits on access to the lab space when working; • no smoking, eating, drinking, storage of food in laboratory; • care to minimize splashes and actions that may create aerosols (tiny droplets); • decontamination of work surfaces after every use after any spills; (continued on next slide)
Biosafety Level 1 (BSL-1) • Standard practices (continued): • decontamination of laboratory wastes; • use of mechanical pipettes only (no mouth pipetting); • "sharps" precautions, including special containers for disposing of needles and other sharp objects; • maintenance of insect/rodent control program; • use of personal protective equipment (lab coats, latex gloves, eye protection or face shields) • Open bench top sink for hand washing
Biosafety Level 2 (BSL-2) • Agents associated with human disease • Generally required for any human-derived blood, bodily fluids, tissues in which infectious agent may be unknown • Agents include measles virus, Salmonella species, pathogenic Toxoplasma, Clostridium botulinum, hepatitis B virus (transmission electron micrograph of hepatitis B virus)
Biosafety Level 2 (BSL-2) • Primary hazards: • accidental needle sticks • exposure to eyes and nose (mucous membranes) • ingestion of infectious materials • Agents do not cause lethal infections, are not transmissible via airborne route • (do not cause infection if tiny droplets become airborne and are inhaled, which might occur if the material were spattered) • Agents are pathogens for which immunization or antibiotic treatment is available • Extreme care should be taken with contaminated needles and sharp lab instruments
Biosafety Level 2 (BSL-2) • Standard practices include BSL-1 plus: • policies to restrict access to lab; • biohazard warning signs posted outside lab; • surveillance of laboratory personnel with appropriate immunizations offered; • biosafety manual with definitions of needed waste decontamination or medical surveillance policies; • supervisory staff who have experience working with infectious agents and specific training for laboratory personnel in handling these agents
Biosafety Level 2 (BSL-2) • Primary barriers: biosafety cabinets or other approved containment devices • Personal protective equipment: lab coats, gloves, face protection as needed • Protective clothing removed when personnel leave laboratory area • Cabinets thoroughly decontaminated daily and monitored for radiation for personal protection • Secondary barriers: BSL-1 barriers plus autoclave for glassware
Biosafety Level 2 (BSL-2) • Example of biosafety sign posted outside lab working with infectious agents Lab’s biosafety level Infectious agents under study Contact information for responsible person and 2 emergency contacts
Biosafety Level 3 (BSL-3) • Agents with potential for respiratory transmission, may cause serious and potentially lethal infection • May be studied at BSL-2 for diagnosis • Agents include Mycobacterium tuberculosis,St. Louis encephalitis virus, Francisella tularensis, Coxiella burnetii (F. tularensis under direct fluorescent antibody stain)
Biosafety Level 3 (BSL-3) • Primary hazards: needle sticks, ingestion, exposure to infectious aerosols • For example: • Public health surveillance for West Nile virus includes testing birds • In August 2002, state laboratory worker cut finger while dissecting bird; 4 days later, had symptoms of fever, myalgia, recurring sweats, hot flashes • Worker and bird both diagnosed with West Nile • 2 other lab-acquired cases in 2002
Biosafety Level 3 (BSL-3) • Tularemia common source of laboratory-acquired infection • infections occur while handling infected animals or experimenting with cultures • Laboratory-acquired infections known to occur but not reportable before 9/11/2001 • Tularemia now classified as potential biological weapon
Biosafety Level 3 (BSL-3) • Standard practices include BSL-2 plus: • strictly controlled access to the lab; • specific training for lab personnel in handling potentially lethal agents; • decontaminating all waste; • changing contaminated protective lab clothing, decontaminating lab clothing before laundering; • institutional policies regarding specimen collection and storage from workers to establish exposure
Biosafety Level 3 (BSL-3) • Primary barriers: • Similar to BSL-2 personal protective equipment • Respiratory equipment if risk of infection through inhalation • Secondary barriers: • All BSL-2 barriers • Corridors separated from direct access to lab • Access through self-closing double doors • Air handling systems to ensure negative air flow (air flows into the lab) • Air pumped into lab not re-circulated in building
Biosafety Level 4 (BSL-4) • Dangerous and exotic agents with high risk of life-threatening disease, aerosol-transmitted • Related agents with unknown risk of transmission • Agents (all viruses) include Marburg virus, Ebola virus, viruses that cause Congo-Crimean hemorrhagic fever, Lassa fever (transmission electron micrograph of Ebola virus)
Biosafety Level 4 (BSL-4) • Primary hazards: • respiratory exposure to infectious aerosols • mucous membrane exposure to infectious droplets • accidental sticks with needles or other sharp objects contaminated with infectious material • For example • In late 1960s, 25 laboratory-acquired Marburg infections, including 5 deaths • Workers studying infected monkeys from Uganda • First documented naturally-occurring human case occurred in 1975
Biosafety Level 4 (BSL-4) • Personnel must receive specialized training in handling extremely dangerous infectious agents, containment equipment and functions • Access to lab is restricted: immunocompromised persons are never allowed to enter the lab • Standard practices include BSL-3 plus: • strictly controlled access to the laboratory; • changing clothing before entering and exiting lab (showering upon exiting recommended); • decontaminating all material exiting facility
Biosafety Level 4 (BSL-4) • Primary barriers: • Biosafety cabinets used at other biosafety levels • Full-body, air-supplied, positive pressure personnel suit • Secondary barriers: • All physical barriers at BSL-3 • isolated zone or a separate building; • dedicated supply and exhaust, vacuum, decontamination systems; • a recommended absence of windows (or sealed and resistant to breakage)
Laboratory Locations • BSL-1: high schools, community colleges, municipal drinking water treatment facilities • BSL-2: local health departments, universities, state laboratories, private laboratories (hospitals, health care systems), industrial laboratories (clinical diagnostic companies) • BSL-3: state health departments, universities, private companies, industry, federal government (NIH, CDC) • BSL-4: only 15 facilities in the US • 9 federal (CDC, NIH), 4 university (Georgia State University, University of Texas Medical Branch), 1 state, 1 private • Renovations underway at several labs, new facilities proposed at additional sites
Summary • Laboratorians have long recognized hazards of processing infectious agents • Biosafety guidelines developed to protect workers in microbiological and medical labs through a combination of safeguards including engineering controls, management policies and work practices. • Issue described differences between biosafety levels • Help you understand process labs may have to undertake to identify microorganism, why every lab cannot test for every organism
References • US Department of Health and Human Services, Centers for Disease Control and Prevention and National Institutes of Health. Biosafety in Microbiological and Biomedical Laboratories. 5th ed. Washington, DC: US Government Printing Office; 2007. http://www.cdc.gov/od/ohs/ biosfty/bmbl5/bmbl5toc.htm. Accessed February 6, 2008. • Clemson University Environmental Health and Safety. Biological Safety [online training]. http://ehs.clemson.edu/training/biosafety/index.html. Accessed February 6, 2008. • Centers for Disease Control and Prevention. Laboratory-Acquired West Nile Virus Infections — United States, 2002. MMWR Morb Mort Wkly Rep. 2002; 51:1133-1135. http://www.cdc.gov/mmwr/preview/ mmwrhtml/mm5150a2.htm. Accessed February 6, 2008. • United States Government Accountability Office. High-Containment Biosafety Laboratories: Preliminary Observations on the Oversight of the Proliferation of BSL-3 and BSL-4 Laboratories in the United States. Publication GAO-08-108T. http://www.gao.gov/docsearch/ abstract.php?rptno=GAO-08-108T. Published October 4, 2007.
