PMTP Chapter 7

• Biosafety level


  Level 1-4 determined by the CDC/NIH
• Selection of biosafety level

  • Based on characteristics of the infectious agent: pathogenicity, documented route of transmission, availability of protective immunization or effective therapy, risk of exposure created by manipulation and handling the agent and caring for infected animals
• Biosafety levels


  • BSL1 - agents not known to cause disease
  • BSL2 - agents associated with human disease
  • BSL3 - indigenous/exotic agents associated with human disease and potential for aerosol transmission
  • BSL4 - dangerous/exotic agents of life threatening nature
• Biosafety levels provide


  • Increasing levels of personnel & environmental protection
  • Appropriate guidelines for: Laboratory Practices and Techniques, Standard Practices and Special Practices, Knowledge of supervisor and personnel, Lab specific SOPs/Biosafety manual, Safety Equipment (Primary Barriers), Laboratory Facilities (Secondary Barriers), Buildings (Tertiary Barriers)
• Proper handwashing


  1. Wash with warm, running water, mild, preferably liquid soap (doesn't have to be antibacterial)

  2. Rub hands together vigorously for at least 15 seconds: scrub between fingers, under nails, tops & palms of hands

  3. Rinse with warm, running water

  4. Dry with disposable paper towel

  5. Use lotion to prevent chapping of hands
• Basic Personal Protective Equipment (PPE) required at all Biosafety Levels

  • Lab coat
  • Disposable latex/non-latex exam gloves - change when torn or contaminated
  • If risk of splashes or aerosols, protect the eyes & face: safety glasses/goggles, face mask
  • If necessary, other PPE should be worn, including: gown, face shield, booties
• Biosafety Level 1 (BSL1)


  • Suitable for work involving well-characterized agents not known to cause disease in healthy adults and of minimal potential hazard to lab personnel and the environment
• BSL1 agents


  • Bacillus subtilis
  • Naegleria gruberi
  • Infectious canine hepatitis virus
  • Non-entero hemorrhagic E. coli
  • Exempt recombinant DNA experiments
• Biosafety Level 2 (BSL2)


  • Suitable for work involving agents of moderate potential hazard to personnel and the environment, where immunization or antibiotic treatment is available
• All Biosafety Level 2 (or higher) labs are inspected to assure they meet the CDC/NIH guidelines
• Biosafety Levels 1-2 Facility Design Guidelines

  • Lab doors are lockable
  • Sinks available for hand washing
  • Work surfaces easily cleaned, impervious to water
  • BSL2 labs should be under negative pressure, air flows into lab and doesn't re-circulate to non-lab areas
• Additional Requirements for Biosafety Levels 1-2

  • Biosafety Cabinet
  • Autoclave
  • Eye Wash
• Biosafety Levels 1-2 Standard Microbiological Practices

  • Restrict/limit access when working
  • No eating, drinking, storing food, etc.
  • No mouth pipetting
  • Minimize splashes and aerosols
  • Decontaminate wastes
  • Decontaminate work surfaces daily
  • Maintain insect & rodent control program
  • Extreme precaution with SHARPS
  • Gloves and additional PPE
  • Use of mechanical pipetting devices
  • Extra care when using any contaminated sharp item
  • Plastic should be substituted for glass whenever possible
  • Used disposable needles must not be bent, sheared, broken, recapped, removed from disposable syringes, or otherwise manipulated by hand before disposal - always dispose of whole unit in SHARPS containers
• MIOSHA Occupational Exposure to Bloodborne Diseases Standard applies to all jobs where there is a potential for exposure to human bloodborne diseases, including healthcare workers, laboratory workers, firefighters, EMTs, custodians and maintenance workers, etc.
• Retraining is required annually for the MIOSHA Occupational Exposure to Bloodborne Diseases Standard
• Universal Precautions


  Treating all human blood, tissue, cells, etc. as if they ARE infectious
• Bloodborne Diseases


  • HIV: Human Immunodeficiency Virus causes AIDS - no cure or vaccination
  • HBV: Hepatitis B virus causes liver disease - vaccination available
  • HCV: Hepatitis C virus causes liver disease - no vaccination available
• Bloodborne diseases


  Only spread when blood and certain other body fluids from an infected source get into the bloodstream of an uninfected person
• Occupational exposure


  • Needlestick or cut with contaminated sharp object
  • Cuts/breaks in skin
  • Mucous membranes (eyes, nose, mouth)
• Bloodborne Diseases are NOT transmitted through


  • Kissing or hugging
  • Sneezing or coughing
  • Food or water
  • Sharing eating utensils, cups, etc.
  • Casual contact
  • Saliva, tears, perspiration, urine, feces (when there is no blood present)
• How HIV is Transmitted

  • Blood and body fluids: serum, semen, vaginal secretions, fluids around internal organs/systems
  • IV drug use
  • Vaginal or anal intercourse
  • Mother to child in utero
• Rate of seroconversion after needlestick exposure to infective material from HIV+ person


  0.3% or about 1 in 300
• HIV is in high concentration during period prior to antibody development, and is much less infective than HBV, HCV, Herpes
• Factors associated with HIV transmission in healthcare

  • Deep injury
  • Device visibly contaminated with source patient's blood
  • Procedures involving a needle placed directly in a vein or artery
  • Terminal illness in source patient
  • No zidovudine (AZT) prophylaxis
• Hepatitis B Virus (HBV)


  • Inflammation of the liver - most common bloodborne disease
  • Symptoms range from flu-like to none at all - person can still be infectious and can spread the disease
  • Incubation period from 28-160 days
  • Symptoms may include: loss of appetite, fatigue, fever, possible jaundice and dark urine
  • HBV is a much greater risk on the job than HIV, especially if you are not vaccinated
• Fluids that pose risk of HBV infection

  • Blood and blood products
  • Body fluids containing visible blood
  • Semen and vaginal secretions
  • Breast milk
  • Saliva (through a human bite)
• How Hepatitis B can be transmitted in the workplace


  • Needlesticks or cuts with sharp, contaminated objects
  • Splashes to eyes/nose/mouth
  • Contact with broken skin
  • Human bites that break the skin
• Hepatitis B Virus


  Inflammation of the liver - most common bloodborne disease
• Hepatitis B Virus


  • Symptoms range from flu-like to none at all
  • No symptoms - person can still be infectious and can spread the disease
  • Incubation period from 28-160 days
  • Symptoms may include: loss of appetite, fatigue, fever, possible jaundice and dark urine
• Hepatitis B is a much greater risk on the job than HIV, especially if you are not vaccinated
• Fluids that pose risk of infection

  • Blood and blood products
  • Body fluids containing visible blood
  • Semen and vaginal secretions
  • Breast milk
  • Saliva (through a human bite)
• How Hepatitis B can be transmitted in the workplace

  1. Needlesticks or cuts with sharp, contaminated objects

  2. Splashes to eyes/nose/mouth

  3. Contact with broken skin

  4. Human bites that break the skin
• Prior to vaccination, it was estimated that more than 12,000 healthcare workers were occupationally infected with HBV annually, resulting in 250 deaths
• In 1983, the incidence of HBV among healthcare workers was 3 times higher than in the general population, but by 1995 it was 5 times lower
• The advent of the HBV vaccine was a major advance in preserving health and lives of healthcare workers
• Hepatitis B Vaccination


  • Administered in 3 shots over 6 months
  • Engerix-B Vaccine is yeast derived - no chance of infection from vaccination
  • Provides long term protection against HBV for 96% of healthy adults: no booster recommendation by CDC at this time
  • Post exposure vaccination is 70-88% effective when started within one week
• Hepatitis C Virus


  • Spread primarily through blood/blood products, less likely to be spread sexually
  • If left untreated, 80-85% of cases become chronic
  • There is no vaccine for HCV
• Based on limited studies, risk for infection after needlestick is approximately 1.8%
• • Hepatitis C was identified in 1988, formerly called non-A non-B hepatitis - called "silent epidemic"
  • Blood supply not tested until early 90s
  • Most common chronic bloodborne infection in U.S.
  • Incubation period from 2-26 weeks, most people never have symptoms
• Generation of Aerosols


  1. If aerosols may be generated, work must be performed in Class II biosafety cabinet

  2. Procedures that may generate aerosols include: Pipetting, Centrifugation, Tissue culture, Sonication, Blending of tissues, Animal inoculations