EMD 545 b Lecture #7 Controls in Biosafety III Decontamination and Emergency Response
Decontamination n Encompasses: ¨ antisepsis, disinfection, decontamination, and sterilization ¨ Antisepsis n chemical applied to living tissue that will control or arrest the growth of a microorganism ¨ Decontamination n disinfection or sterilization of contaminated materials
Decontamination n Disinfection ¨ To free from infection, reduction of contaminant load to a safe level, does not imply total destruction of all microorganisms. Will not always destroy spores. n Sterilization ¨ The destruction of all forms of microbial life. Difficult to achieve (usually referred to a very low chance that a microbe survived).
Disinfection in Healthcare n High-Level Disinfection ¨ sporicidal/tuberculocidal (but used for shorter times than required for sterility). Equipment that will have invasive contact with patient. n Intermediate ¨ tuberculocidal (equipment that will contact mucous membranes of patient) n Low-level (kills vegetative bacteria) ¨ for non-critical equipment (no invasive contact)
Sterilants - Physical Methods n Steam Autoclave ¨ steam under pressure --> moist heat ¨ 121 C/250 F @ 15 psi for 30 - 60 minutes n Dry Heat ¨ 160 n - 170 C/320 - 356 F for 2 - 4 hours Incineration ¨ 2 stage burn, 1400 & 1800 F
Sterilants - Gases n Formaldehyde gas ¨ heat formalin to vaporize it (1 ml/ft^3) ¨ heat paraformaldehyde (0. 3 g/ft^3) ¨ 2 hour exposure time required (8 hour or overnight contact period recommended) ¨ can neutralize HCHO (toxic, suspect carcinogen) with ammonium bicarbonate ¨ room temperature > 70 F, %RH - > 70%
Sterilants - Gases n Ethylene Oxide ¨ 400 - 800 mg/L ¨ 35 - 60 C temperature, 30 - 60% RH ¨ contact time up to 4 hours n Hydrogen Peroxide ¨ vaporize from 30% H 2 O 2
Liquid Disinfectants Surface treatment or to treat liquid waste n Inactivate by n ¨ coagulation, denaturation, lysis, enzyme inactivation n Factors to consider: temperature, humidity, p. H n contact time, concentration n penetrability n presence of organic material n
Liquid Disinfectants n Alcohol ¨ Ethanol, n Isopropanol ( 70 - 85%) requires presence of water for protein denaturation ¨ bactericidal (vegetative bacteria) ¨ virucidal (enveloped viruses) ¨ Not sporicidal ¨ Not as effective against non-enveloped viruses) ¨ flammable ¨ low BP, higher evaporation rate, difficult to get 10 minute contact time
Liquid Disinfectants n Glutaraldehyde ¨ stable in and stored in acid p. H range ¨ activated by adding sodium bicarbonate to elevate p. H to > 7. 5 (14 day shelf-life) ¨ contact time (10 - 180 minutes) ¨ sporicidal at longer contact times n sterility requires 6 - 10 hours ¨ non-corrosive ¨ effective in presence of organic material
Liquid Disinfectants n Formaldehyde (4 - 8 %) ¨ active in alkaline p. H range, non-corrosive ¨ effective in presence of organic material ¨ diminished activity in colder temperatures ¨ 10 - 30 minute contact time required ¨ fixative (penetration rate of 8 mm/24 hours in tissue specimens) ¨ wide spectrum disinfectant ¨ suspect carcinogen, toxic at low levels
Liquid Disinfectants n Phenol (0. 2 - 3%) ¨ Not sporicidal, not effective against nonenveloped viruses ¨ Tuberculocidal, fungicidal, bactericidal ¨ not affected by presence of organic material ¨ hard water can affect effectiveness ¨ Toxic, can be absorbed through skin (large spills to skin can be fatal)
Liquid Disinfectants n Quaternary Ammonium Compounds (0. 1 - 2%) ¨ cationic detergents, very good cleaning agents ¨ inactivated by organic material ¨ bactericidal, algicidal, fungicidal, will destroy enveloped viruses ¨ not tuberculocidal or sporicidal ¨ low-level disinfectant ¨ good for general surfaces and floors ¨ very toxic to eyes (a few drops can lead to blindness)
Liquid Disinfectants n Halogens - chlorine (0. 01 - 5%) ¨ wide spectrum of activity ¨ acts rapidly at low concentrations (10 - 30 min. ) ¨ inactivated by organic material (use more) ¨ will lose chlorine upon exposure to light/air ¨ more cidal at low p. H, good at lower temps. ¨ very corrosive
Liquid Disinfectants n Halogens - Iodine (0. 47%, 75 - 1600 PPM) ¨ inactivated by protein ¨ 1600 PPM inactivates wide spectrum of agents ¨ effective over wide p. H range ¨ tuberculocidal, sporicidal ¨ corrosive, will stain, toxic, allergenic ¨ Dilution issue - must follow recommended dilutions for iodophors (or iodophor may not be as effective)
Liquid Disinfectants n Hydrogen Peroxide (3% - 25%) ¨ stable, non-toxic, fast acting ¨ 10 - 25% solutions are sporicidal ¨ inactivated by organisms that produce catalase
Rank Order of Resistance to Disinfection n n n n Prions Protozoan cysts Bacterial spores Non-enveloped (hydrophilic) viruses Mycobacteria Fungal spores, fungi Vegetative bacteria Enveloped viruses (lipophillic)
Verification of Decontamination n Autoclave tape ¨ time/temperature/date n records on chart Chemical indicators (diack melt pellets) ¨ fuse if temperature reached for at least 1 second n Biological Spore indicators ¨ Bacillus stearothermophillus ¨ Bacillus subtilis var. niger n Manifest for biomedical waste (incineration)
Emergency Response n Percutaneous exposure ¨ immediately wash well with soap & water ¨ wash should last 15 minutes n dilution of wound most important, soap & water most readily available cleanser ¨ Notify supervisor (if available) don’t let this delay medical attention n inform that you are heading to Health Services n ask them to initiate incident report (mail to Health Services later) - start review of incident n
Emergency Response n Percutaneous exposure ¨ seek medical assistance within 1 -2 hours verify proper cleansing n baseline serum taken, tested initiated if appropriate n post-exposure prophylaxis provided if necessary n counseling offered n n Before initiating work: ¨ ensure working sink, soap, paper towels present ¨ suitable disinfectant if used
Emergency Response n Facial mucous membrane contact n (eyes, nose, mouth) ¨ wash n well in eye wash for 15 minutes eye wash station checked weekly flow will hit eyes/face (strength, direction) ¨ clear, clean water ¨ unit can be activated for hands-free operation in 1. 5 seconds ¨ hold eyelids open with hands n know location of eyewash and how to use before starting work n vision may be impaired in exposure situation n
Emergency Response n Aerosol exposure ¨ BL 2 leave lab upon release n Wash wounds, flush face/eyes if exposed, wash hands n post sign, keep area vacated for 20 - 30 minutes to allow aerosols to settle n decontaminate personnel clothing, skin n notify lab supervisor, biosafety, and Health Services if necessary n
Emergency Response n Aerosol exposure ¨ High risk BL 2, BL 2+, BL 3 hold breath, drop gloves on floor, and immediately proceed to the anteroom n remove all lab clothing and any personal clothing that may have been contaminated n wash all exposed skin surfaces, hands n post sign to alert of spill n
Emergency Response n Aerosol exposure verify airflow direction into lab n call safety, principal investigator n no entry until joint risk assessment with safety n all exposed report to Health Service n
Exposure Incident Follow-up n documented written report name, lab, department n date, time, location n description of incident n n risk assessment for health services material involved (biohazard, fixed, etc. ) n wounds, visible cuts on person n route of exposure, estimated dose (concentration/volume) n depth of wound n
Exposure Incident Follow-up n Experience of person involved ¨ safety training records ¨ prior accidents/exposures n Object/items involved ¨ sharps (type, brand, reusable/disposable) ¨ location of needlebox ¨ animals n During preparation/use/disposal/cleaning?
Exposure Incident Follow-up ¨ Appropriate n onsite response after incident? wash, report, visit to Health Services ¨ Personal protective equipment worn at time ¨ Engineering controls in use? ¨ What were the safety practices at time? ¨ How is the area decontaminated/cleaned? What is their plan to prevent recurrence? n What can you add after the review? n Write up new SOP and check periodically n
Accidents & Illnesses prompt reporting n immediate medical assistance n ¨ serum samples, stool specimens, nasal and skin washings n investigate serious, unusual or extended illnesses
Report of seroconversion examine worker n investigate procedures n revise procedures to eliminate exposure n
Biohazard Spills n BL 1 ¨ can n clean immediately w/ basic PPE Spill in a biosafety cabinet ¨ already contained ¨ can initiate clean-up immediately at all levels ¨ for spills that go into grilles, flood drain pans with disinfectant (ensure that drain is closed) and call safety for evaluation more extensive decon may be needed
Biohazard Spills n BL 2 spill (outside containment equipment) ¨ evacuate lab for 20 - 30 minutes ¨ treat exposed, remove lab clothing, wash ¨ post-sign ¨ call safety if exposure risk (airborne) high defined area on floor, bench? - lab n widespread aerosol throughout room (centrifuge incident) - safety assistance needed n
Biohazard Spills n BL 3 (spill outside containment equipment) ¨ evacuate lab ¨ remove PPE in anteroom (contaminated clothing) ¨ wash/decon all exposed skin surfaces, face & hands ¨ post sign ¨ verify airflow direction ¨ call safety & PI, notify Health Services ¨ lab remains closed until cleared by Safety
Spill Decontamination n Spill kit (assembled in advance, kept in BL 1, BL 2 labs, outside of BL 3 labs) ¨ concentrated disinfectant (appropriate for agent in use) ¨ paper towels, biohazard bags ¨ squirt bottle ¨ sharps container, forceps/tongs ¨ lab coat/gown, gloves, utility gloves ¨ full face protection, booties ¨ respiratory protection as required
Spill Decontamination n COVER n n cover spill area with paper towels DISINFECT slowly pour disinfectant around perimeter and into the center of spill area. 10 -15 minute contact time. n Clean/disinfect surrounding areas n n CLEAN n n absorb spill and paper towels and place in biohazard bag. Sharps placed in sharps container. DISINFECT n spray spill area with disinfectant, allow to air dry
Mixed Biohazard Spill n Chemical/biohazard spill ¨ will chemical inactivate the biohazard? ¨ is chemical a listed hazardous or toxic waste? ¨ chemical safety risk assessment (PEL, TLV, exposure routes, chemical PPE) ¨ chemical neutralizers or absorbents used ¨ inactivate biohazard component of waste and discard as hazardous chemical waste ¨ check for incompatibilities with proposed disinfectant
Mixed Biohazard Spill n Radioactive/biohazard spill ¨ again, more regulated waste takes precedence ¨ inactivate the biohazard component and discard as radioactive waste ¨ avoid bleach with 125 -I (radioiodine gas may be released) ¨ booties required for radioactive spill ¨ Geiger-mueller, Scintillation probes (Na. I), Liquid Scintillation Counters to determine scope of radioactive contamination
BL 3 Emergency Response n Airflow alarm in BL 3 lab - work in progress ¨ all work under containment ¨ stop work @ time of alarm, remove outer gloves, verify airflow reversal ¨ if verified, cap all cultures and return to incubator or freezer ¨ decontaminate work surfaces in biosafety cabinet, leave waste inside cabinet, leave cabinet on ¨ remove PPE, leave lab, post “lab down” sign, and notify safety, PI, and maintenance
BL 3 Spill @ time of Airflow Alarm n n n Worst-case breach Verify interlock of supply with exhaust ¨ did supply also shut down? ¨ is air movement neutral and not out of lab? ¨ duct tape around entire door to seal in lab ¨ shut exhaust/supply dampers to/from BL 3 lab ¨ if breach, may have to evacuate adjacent rooms, floor, building? ? ? ¨ Rapid notification to safety, PI, maintenance Why redundancy/emergency power so important in BL 3 labs!
Non-Ambulatory Researcher in BL 3 Lab n Prompt notification ¨ 2 person team approach ¨ good visual access inside the lab ¨ video surveillance ¨ method of communication outside the lab n Consider person and all clothing contaminated ¨ EMT’s w/ PPE enter with support or safety personnel ¨ EMT’s provide medical assistance ¨ Safety or support cuts off/removes/decontaminates PPE and regular clothing n 2 EMT’s outside lab awaiting transfer of patient
Non-Ambulatory Researcher in BL 3 Lab n Decontaminate EMT’s equipment ¨ may n Evaluate contamination of laboratory ¨ gas n have to buy new supplies (BSL 3 stigma) decontamination may be required Level of coordination must be practiced ¨ schedule n drills periodically Always hold a post-incident review (lessons learned) session - will benefit all involved
Maintain a spill kit for cleaning biological spills. Keep the spill kit outside the BSL-3 Lab (to prevent contamination of supplies)
Biohazard Spills n BSL-3 (spill outside containment equipment) ¨ evacuate lab ¨ remove PPE in anteroom (contaminated clothing) ¨ wash/decon all exposed skin surfaces, face & hands ¨ post sign ¨ verify airflow direction ¨ call safety & PI, notify Health Services ¨ lab remains closed until cleared by Safety
Spill Decontamination – BSL-3 n Confine spread of contamination to smallest possible zone ¨ HEPA filtered space? ¨ Exhaust location? Notify Plant Maintenance n Determine extent of contamination within zone ¨ Exposed n Environmental stability of spilled agent? ¨ Is n personnel to Employee Health after decon time on your side? Wait it out Unique requirements for agent? (immunization, PPE – any responders at high risk? ¨ Default to HEPA-filtered PAPR for emergency entry
Spill Decontamination – BSL-3 n n n What is the 99. 9% particle clearance time for the BSL-3 Lab in minutes? Is manual facility chemical decontamination sufficient? Which chemicals are effective? Determine need for Space Decontamination ¨ How sealed/sealable is the space? ¨ Can you achieve parameters required decon? n n for space Select remediation plan with incident commander (EHS, FD, FBI? ) – Level A/B/C/D Response? Are clearance swab samples/air samples required to document destruction?
Spill Decontamination (Aerosol release throughout laboratory) n Large area decontamination ¨ Gas decontamination Formaldehyde, chlorine dioxide, vaporized H 202? n Outside vendor? EH&S? n Sealed laboratory? n ¨ Liquid n Chemical Decontamination Foggers, sprayers? ¨ Contact time? Biological indicators? ¨ Process verified/lab cleared prior to reuse
Spill Decontamination – BSL-3 n Release of a Select Agent from BSL-3 lab? ¨ Immediate n agency notifications by RO/ARO Public Health Risk from release of agent? ¨ Public Affairs Office (EHS Director, CEO) ¨ City/Town Dept. of Public Health ¨ State Dept. of Public Health ¨ CDC? n Lessons learned meeting? ¨ Was response protocol effective? ¨ Identify areas of improvement?
Spill Decontamination n COVER n n cover spill area with paper towels DISINFECT slowly pour disinfectant around perimeter and into the center of spill area. 10 -15 minute contact time. n Clean/disinfect surrounding areas n n CLEAN n n absorb spill and paper towels and place in biohazard bag. Sharps placed in sharps container. DISINFECT n spray spill area with disinfectant, allow to air dry
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