aerosol transmissable diseases · 2019. 12. 16. · incidents involving atps are difficult to...
TRANSCRIPT
AEROSOL TRANSMISSIBLE DISEASESCMU OFFICE OF LAB AND FIELD SAFETY
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TRAINING OVERVIEW
Define laboratory acquired infections
Identify the occupational risks and hazards of working with
aerosol transmissible pathogens (ATPs)
Identify requirements for handling of aerosol transmissible
pathogens with specific laboratory equipment
Identify proper steps to take in the event of an incident
involving aerosol transmissible pathogens
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LABORATORY-ACQUIRED INFECTIONS
Laboratory-acquired infections (LAIs) are defined as all
infections acquired through laboratory or laboratory-related
activities regardless of whether they are symptomatic or
asymptomatic in nature. Ex. Mtb
Check out the ABSA International LAI Database @
https://my.absa.org/LAI
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POSSIBLE ROUTES OF EXPOSURE FOR
LABORATORY-ACQUIRED INFECTIONS
Contact between mucous membranes and
contaminated material
• Contaminated surfaces or hands, direct splashes/droplets
Ingestion
• Aspiration through a pipette, smoking or eating in lab
• Ingestion following application of cosmetics and lipstick in
the lab
Percutaneous inoculation
• Needle and syringe, cuts or abrasions from contaminated
items, animal bites
Inhalation
• Aerosols-most relevant to this training! 4
AEROSOLS
An aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas
An aerosol is the most common source of LAIs, WHY?
Not as easily detected as a needle stick, animal bite, or splash
Multiple infections from single exposure incident
Aerosols are generated by many common laboratory techniques, examples include: sonicating, vortexing, pipetting
Any time energy is applied to a microbial culture, aerosols may be generated!
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AEROSOL TRANSMISSIBLE DISEASES
Aerosol transmissible diseases
(ATDs) are caused by pathogenic
microbes called aerosol
transmissible pathogens (ATPs)
These microbes can be spread when
an infected person coughs, sneezes or
laughs
The microbes are able to remain
suspended in the air and may travel
several feet before settling
The primary method of contracting an
ATD is through inhalation of these
microbes
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EXAMPLES OF AEROSOL TRANSMISSIBLE
PATHOGENS
Examples include:
Mycobacterium tuberculosis
Brucella spp.
Bordetella pertussis
Measles virus
Rabies virus
Varicella zoster virus
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MYCOBACTERIUM TUBERCULOSIS
Tuberculosis (TB) is one of the most widely
recognized ATDs
Not everyone that contracts TB becomes ill
~5% of infections active TB
~95% of infections latent TB (~10%
reactivate; cannot spread to others)
When TB does cause illness, it can infect any part
of the body
Active TB is called TB disease
Most common site for TB disease is the lungsFilm chest x-ray show interstitial infiltrate both
lungs due to Mycobacterium tuberculosis infection
(Pulmonary Tuberculosis). Photo Credit:
stockdevil/iStock/Getty Images8
SYMPTOMS AND TREATMENT OF TB DISEASE
Individuals with latent TB do not display symptoms
Symptoms of TB disease vary depending on the location of the bacteria
Symptoms of TB disease in the lungs are:
Left untreated, TB can spread beyond the lungs and cause death
Most forms of TB (including lab strains) are diagnosable and treatable, you’ll
be work with the Mtb strain H37Rv9
Severe cough lasting longer
than three weeksChest pain
Coughing up blood or sputum
Weakness
Weight loss Loss of appetite Fever
TB – LAB RISKS
Primary route of transmission is inhalation of TB containing
aerosols
Secondary routes of transmission (uncommon in laboratory)
include ingestion and direct inoculation
TB-causing bacteria can remain viable for extended periods
in the environment
Infectious dose is estimated to be < 10 bacilli by inhalation
for humans
In animal studies, infectious doses range from 1 organism
to 1,000 organisms, depending on the susceptibility of the
species10
TB – LAB RISKS
Risk is elevated in labs that manipulate cultures
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IDENTIFYING REQUIREMENTS FOR PROPER
HANDLING OF AEROSOL TRANSMISSIBLE
PATHOGENS WITH SPECIFIC LABORATORY
EQUIPMENT
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REDUCING THE RISK OF LABORATORY-
ACQUIRED INFECTIONS
Factors contributing to
the reduction in LAIs
may include
improvements in
containment equipment,
engineering controls,
and an increased
emphasis on safety
training
0
200
400
600
800
1000
1200
1930-1950 1951-1978 1979-2004
Fungi
Rickettsia
Viruses
Bacteria
Parasites
Source: Harding, A.L., Brandt Byers, K.. Epidemiology of laboratory–associated infections. In Fleming, D.O. and Hunt.
D.L. Biological Safety: Principles and Practices. 4th edition. Washington, DC: ASM Press, 2006; 53-77.
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Symptomatic LAIs by Time Period and Agent Category
REDUCTION OF LAB RISKS
Elements that must be in place to reduce risks of TB exposures
include:
1. Careful risk assessment of all procedures, equipment and techniques
2. Properly maintained and certified/calibrated/monitored equipment
3. Appropriate laboratory design and facilities
4. Job appropriate medical surveillance program
5. Thorough personnel training program
6. Appropriate waste handling
7. Well reviewed SOPs and safety policies 14
MITIGATION OF BIOAEROSOL EXPOSURE
The use of engineering controls (for example,
biological safety cabinets [BSCs] and room ventilation)
and personal respiratory protection (such as
respirators) can help prevent inhalation of infectious
aerosols
However, the most important consideration in
reducing the risk of infection in the laboratory is to
minimize the production of aerosols
All aerosol generating procedures with open
containers MUST be conducted in the BSC15
MITIGATION OF BIOAEROSOLS – PIPETTING
TECHNIQUES
Pipetting techniques that can reduce the risk of creating bioaerosols when manipulating
TB material include:
Do not forcibly expel infectious liquids from a pipette, stop at the first ‘stop’
Do not forcibly expel air from a pipette into potentially infectious liquids
When using a pipette to add a reagent to a potentially infectious liquid, place the
pipette against the inner wall of the container and gently expel the fluid or hold the
pipette on an angle so that the liquid runs down the side of the tube
Ensure that when expelling liquids, tubes are held on angle so that the liquid runs
down the side of the tube or waste container to minimize any splashes
Only insert the disposable tip of a micropipette into a tube or container, NEVER
submerge the barrel of a micropipette, exceptions include…disinfecting the pipette
Do not mix or suspend infectious materials by repeatedly filling and fully emptying a
pipette, exceptions include…breaking up the Mtb pellet
With serological pipettes don’t draw up into the pipette pump.
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MITIGATION OF BIOAEROSOLS –
CENTRIFUGING TECHNIQUES
When centrifuging a specimen or culture, do so
in a sealed safety cup or sealed rotor to avoid
releasing an aerosol into the centrifuge and
laboratory.
Following centrifuging, place containers inside
the BSC.
Allow aerosols to settle (approx. 10 mins) tube
to.
Always open safety cups or sealed rotors inside
a BSC.
Question: Why is it important to open safety
cups or sealed rotors inside the BSC? If a spill
has occurred in the cups, the BSC will help mitigate
spreading the aerosol.
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MITIGATION OF BIOAEROSOLS –VORTEXING
TECHNIQUES
Never vortex an open tube; always ensure
that screw caps/snap caps are securely
fastened to tubes before vortexing or shaking.
(Do not vortex tubes with cotton plugs or
rubber stoppers.)
Allow aerosols to settle (approx. 10 mins).
Always open vortexed tubes inside a BSC.
Vortexer MUST be placed in the BSC. 18
MITIGATION OF BIOAEROSOLS – REMOVING
TEST TUBE CAPS
Always avoid disrupting a bubble or film in an open culture tube. This may be avoided by replacing the cap, gently tapping the top of the tube, set the tube aside and allowing any generated aerosols to settle before reopening.
Tubes can ONLY be opened in the BSC.
Question: Does opening this type of lid create an aerosol? It is highly likely, remember any time energy is applied to a microbial culture, aerosols may be generated!
Question: How could we reduce or prevent an aerosol from being created? Add a disinfectant-soaked towel to the top of the tube while opening or use a lid opener 19
MITIGATION OF BIOAEROSOLS – BLENDING
AND HOMOGENIZING
Use a laboratory blender/bead beater
with a tight‐fitting gasketed lid and
leak‐proof bearings
Allow aerosols to settle (approx. 10
mins).
Bead beater MUST be used in the BSC.20
MITIGATION OF BIOAEROSOLS – USING BLUNT
NEEDLES
If you need to use a needle, use a blunt needle.
When withdrawing a needle from a stoppered bottle, wrap the needle and bottle cap in a disinfectant‐soaked absorbent.
Use syringes with a Luer lock connector.
Dispose of needles directly into sharps container without further manipulation (needle‐cutting devices release aerosols).
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STEPS TO TAKE IN THE EVENT OF AN
INCIDENT THAT MAY HAVE CREATED AN
AEROSOL
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BIOLOGICAL SPILL INSIDE THE BIOSAFETY
CABINET
A small spill completely contained inside the BSC must be cleaned up immediately,
but does not require any further notification
If the spill is severe and you are unsure about whether to report the spill, notify
the Facility Director and BSO
1. Immediately disinfect the spill area in the BSC
2. Place Kimwipe on the spill to absorb liquid
3. Soak the absorbent material with Vesphene, by slowly pour from the outside of
the cloth to the center
4. Allow at least 10 minutes of contact time before placing absorbent material in
the waste container inside the BSC
5. If the spill occurred on the plastic-backed absorbent towel, slowly pour
Vesphene, to decontaminate, wait 10 mins then discard towel and replace
6. The BSC blower is never turned off and the sash should never be closed during
a spill
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“TYPICAL” BIOLOGICAL SPILL OUTSIDE THE
BIOSAFETY CABINET
1. Do not attempt to clean the spill!
2. Alert all personnel in the BSL-3 Facility to evacuate
3. Decon any PPE thought to be contacted by the spill
Try not to track the spill all over
4. Take note of details of spill
5. Follow the lab exit SOP
6. If the lab and anteroom are maintaining negative pressure, remove the PAPR and remain in the anteroom
7. If the lab or anteroom have pressure failure, keep the PAPR on and remain in the anteroom
Once in the anteroom:
Contact the Facility Director, the Biosafety Officer and OLFS immediately
Place a sign reading “Biohazardous Spill- Do Not Enter” from the spill kit on the inside of the door, facing outward through the window
Stay until contacted personnel arrive
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Note: the following steps are related to “typical” spills outside the BSC without an immediate threat to one’s physical
safety, i.e. like an nearby explosion.
For other spill scenarios outside the BSC refer
to the Emergency Response section of the CMU
BSL-3 Facility Laboratory Manual
IDENTIFYING FACTORS OF A POSSIBLE
EXPOSURE
Incidents involving ATPs are difficult to detect, don’t take it upon yourself to
determine exposure
Notify, consult and discuss the incident with the Facility Director and/or the
Biosafety Officer
If a possible exposure has occurred, immediately report to McLaren Central
Occupational Medicine Program (COMP)
If a possible exposure has occurred you may need to file an incident report.
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WHAT TO DO IN THE EVENT OF AN EXPOSURE
OR POSSIBLE EXPOSURE
Notify the Facility Director and/or the Biosafety Officer
Immediately report to McLaren Central Occupational Medicine Program
(COMP), stating that you are an ATD researcher
If COMP is not open, go to McLaren Central Michigan Fast Track or Emergency
Department
Paid employees-Within 24 hours, notify Workers’ Compensation, (989) 774-
7177
Unpaid workers- Within 24 hours, the Facility Director must submit an
Accidental Personal Injury Report form to Risk Management
Immediate response to exposure will reduce your risk of contracting a
laboratory acquired infection 26
NEAR MISSES
A “near miss” is an event where there was almost a spill or an
exposure but an incident did not actually occur
“Near misses” should always be reported to your supervisor
Question: Why should the ‘near misses’ be reported to
your supervisor? We can learn from these ‘near misses’!
Procedures can be updated to reduce the risk of ‘near misses’.
The Facility Director and Biosafety Officer can be consulted for
assistance in devising safety plans
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QUESTIONS?
Any questions or concerns you have can be directed to the Office of Laboratory
and Field Safety
Contact Information
Office number Cell number
Ben Swarts, PhD Facility Director,
Principal Investigator
989-774-2525 216-308-1248
Tom Schultz Biosafety Officer 989-774-3279 989 330-4660
Jennifer Walton, PhD Director, Office of
Laboratory and Field
Safety
989-774-4189 989-621-0785
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