3. Laboratories
Dealing with
Infectious
Materials:
1.Microbiologic-
al laboratory
2. Biochemistry
laboratory
3. Hematology
laboratory
4. Pathology
laboratory
Hazardous
Materials:
Physical (e.g.,
needles, glass).
Chemical (e.g.,
acids, alkalis).
Biological agents
(e.g., clinical
samples,
microbial
cultures)
Biohazardous
Materials
include:
Infectious organisms
(bacteria, fungi,
parasites, prions,
rickettsiae, viruses,
etc.).
Human or primate
tissues, fluids, cells, or
cell culture.
4. Laboratory-acquired infections (LAIs)
are all infections acquired through laboratory activities which
start from collection & transport of specimens till the result is
issued.
Laboratory biosafety
Guidelines developed to protect workers in
microbiological and medical labs through engineering
controls, management policies, work practices
5. Risk factors for LAIs:
1. Sample volume
2. Sample microbial load
3. virulence of the organism
4. Infectious dose of the organism
5. Route of exposure
6. Workload
7. Adherence to safety regulations
8. Host factors (e.g., pregnancy, immunosuppression).
9. Knowledge & experience of the worker.
10. Attitude & habits.
6. ROUTES OF EXPOSURE LAB. PRACTICE
INHALATION Procedures that produce aerosols:
-Centrifugation
-Spills & splashes
-Mixing, vortexing
-Opening sample containers
INGESTION -Mouth pipetting
-Eating, drinking, smoking, nail biting at work
-Splashes into mouth
INOCULATION -Needlesticks
-Cuts from sharp objects
-Animal bites
CONTAMINATION OF SKIN & MUCOUS
MEMBRANES
-Splashes onto m.m. of eyes, nose, mouth
-Contact of blood with skin having small
lesions
7. PATHOGEN (INFECTION)
BACTERIA
COMMENTS
-Brucella (brucellosis) The most frequently reported bacterial LAI.
All species are highly contagious in the lab.
-Mycobacterium tuberculosis (pulmonary T.B.) Infectious dose is very low.
-Neisseria meningitidis (meningitis) Infrequently reported.
Infects by aerosol formation.
-Stool pathogens:
*Salmonella & Shigella
The most commonly reported gastrointestinal
LAIs. Infection occurs by ingestion.
Infectious dose is smaller than other enteric
pathogens.
8. PATHOGEN (INFECTION)
BACTERIA (Continued)
COMMENTS
-Stool pathogens (Continued):
*Escherichia coli O157:H7
*Campylobacter jejuni (enteritis)
Infectious dose is low.
-Rickettsiae:
e.g., Coxiella burnetti (Q fever) The 2nd most commonly reported LIA in the
world. Aerosol transmission. Labs with
animals are at risk.
-Chlamydia psittaci & trachomatis Only sporadic cases are reported.
Cause pneumonitis & lymphadenitis.
9. PATHOGEN (INFECTION) COMMENTS
VIRUSES -Blood-borne pathogens:
Hepatitis B virus
Hepatitis C virus
HIV
-Hemorragic fever viruses:
Transmitted by: parenteral inoculation,
percutaneous contact with infectious material
(blood & other body fluids) in the presence of
skin lesions, exposure of mucous membranes.
Highly infectious by aerosol.
Cause fatal disease.
The most virulent agents are: Ebola, Lassa,
Marburg viruses.
FUNGI -Blastomyces dermatitidis
-Histoplasma capsulatum
-Coccidioides immitis
-Sporothrix schenckii
Infections originate from inhalation of spores.
Cutaneous infections may result from
accidental inoculation.
PROTOZOA -Toxoplasma gondii
-Others: Malaria, leishmania,
trypanosomes
The most frequently observed parasitic LAIs.
In labs with animals, by needlestick injuries.
10. DEFINITION:
*These are guidelines which describe appropriate
containment equipment, facilities & procedures based on dividing
microorganisms into groups according to modes of transmission,
availability of vaccine/or treatment & seriousness of the possible
infection.
*Four biosafety levels (BSLs) are described.
*With class 1 agents, hazards are minimal; class 4 agents
require maximum containment.
11. BSL-1:
-Lowest level of containment.
-For agents which cause no disease in healthy adults (e.g., Bacillus
subtilis)
-Work can be done on open bench.
-Only standard practices are required.
BSL-2:
-For moderate risk agents transmitted by ingestion, percutaneous or
mucous membrane exposure not via aerosols (e.g., Salmonella spp,
hepatitis B virus).
-Ordinary work: on open bench + primary barriers (face protection,
gloves,…).
-If splashes are expected: biosafety cabinets must be used.
12. • 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
– 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
13. BSL-3:
-For hazardous microorganisms transmitted primarily by aerosols (e.g.,
M. tuberculosis, C. burnetti).
-All procedures are done only in biosafety cabinets .
-Specific requirements for lab. e.g., suitable ventilation system.
BSL-4:
-For agents which cause life-threatening disease, transmitted by
aerosol, with no available vaccine or therapy (e.g., hemorrhagic fever
viruses).
-Work is done only in biosafety cabinets: (class III) or (class II +
personnel wearing full-body, air-supplied, positive-pressure suits) .
-The facility is totally isolated from other laboratories & has a
specialized ventilation and waste management system..
14.
15. Comprises 3 aspects:
1. Laboratory practices & techniques.
2. Safety equipment.
3. Laboratory design.
GOAL:
To reduce or eliminate exposure of lab.
Workers (LWs) and the environment to potentially
hazardous agents.
Primary containment: involves protection of personnel and the
immediate environment.
Secondary containment: involves protection of the environment
external to the laboratory.
16. -Hand hygiene:
How ?
Hands must be washed with antiseptic soap or rubbed
with alcohol-based gel
When?
*After removing gloves.
*After handling contaminated materials or surfaces.
*Before leaving the lab.
17. -Protective laboratory clothing:
*Gloves
(well-fitting latex) must be worn for all procedures that
involve direct skin contact with biohazardous material &
are removed when task is completed, when soiled/torn,
before leaving the lab.
*Eye & face
protection are used when splashes expected.
*Footwear
must be with closed toes & heels.
*Clothing
properly fastened & not worn in non-lab areas.
*Open wounds & cuts should be covered with water-
proof dressings.
18.
19. -Waste disposal:
•Sharp objects e.g., needles, scalpels, capillary
tubes, prick instrument, broken slides, broken
contaminated glass, slide covers,…
disposed of in
“sharp containers”
Needles should not be recapped or separated
from the syringe. They should be disposed as
one piece in the sharp container.
20. - Potentially infectious waste (contaminated tubes, used
gloves, used swabs, disposable used petri dishes,…) should
be disposed of immediately at the time of production in
special colored bags with biohazardous label.
- Ordinary waste (paper packs, empty boxes, food remnants,
…) which resembles house waste is disposed of in normal
bags (black).
- Contaminated wastes may be sterilized by autoclaving then
disposed of with the ordinary wastes.
21. -Decontaminate work surfaces & equipment daily & after spills.
-Spills of blood, body fluids or chemicals are considered lab
accidents.
-Small spills are removed with a gloved hand using a small dry
absorbing material, then the area is disinfected using a material
soaked with conc. chlorine-containing disinfectant.
-Large spills are covered with a large absorbing material on which
a chlorine-containing disinfectant is poured, left for 10-15 min then
removed. Area is then disinfected as mentioned above.
22. -Do NOT eat, drink, apply cosmetics or smoke in the lab.
-Do NOT store food in refrigerators used for lab. Purposes.
- Long hair and large veils should be tied back
-Consider all blood & blood-contaminated materials “infected”.
- Pipetting:
*Use disposable plastic pipettes.
*Avoid mouth pipetting & use instead mechanical pipetting
devices.
24. a. Biosafety cabinets (BSCs)
-Biosafety cabinets protect:
1. Laboratory worker & environment
from contaminated spashes & aerosols.
2. Samples & media from being
contaminated.
- BSCs must be tested & certified on a
regular basis.
25. Class I BSCs
-Negative pressure.
-Open front.
-Designed for work with agents of
low to moderate risk (BSL-1 or -2).
27. Class II BSCs
-Negative pressure.
-Open front.
HEPA-filtered vertical laminar airflow.
-Part of the filtered air is recirculated & part is got
rid of.
-Designed for work with agents of BSL-2 or -3.
31. Class III BSCs
-Totally enclosed cabinets.
-Accessible only through glove ports.
-Provides the highest possible level of
protection.
-Designed for work with agents of BSL-3 or
-4).
34. b. Fume hood:
Laboratory fume hoods serve to control
exposure to toxic, offensive or flammable
vapors, gases and aerosols. The laboratory
fume hood is a type of local exhaust ventilation
system (engineering control).
35. • A typical fume hood is a cabinet with a
moveable front sash (window) made out of
safety glass. A properly used and properly
functioning fume hood exhausts hazardous
gases, dusts, mists, and vapors from a
confined location and helps protect
workers from inhalation exposure
36.
37. • c. Safety centrifuge cups prevent
release of infectious agents that can be
transmitted during centrifugation via
aerosols & splashes
38. Basic safety procedures for centrifuges:
*Keep lid closed while centrifuge is
operating.
*If centrifuge vibrates, stop immediately
& check load balances.
*Clean & disinfect after each use.
40. -Laboratory design depends on the type of
microorganisms processed in the lab.
-Most isolates recovered from clinical samples are of
BSL 1 or 2, thus most clinical laboratories must fulfill the
following criteria:
*A space separated from public areas by locked
doors with signs.
*Work surfaces should be nonabsorptive/scratch,
stain, chemical & heat resistant.
41. *Windows prevent entrance of flying insects.
*Ready access to hand-washing sinks
(preferably operated without hands).
*Emergency showers & eye-washing stations
available.
*Air supply of 100% outside air with no
recirculation.
42. The safety program should also include:
*Surveillance for LAIs esp. HBV, HIV & T.B.
*Vaccination plans e.g. HBV vaccine, diphteria/tetanus toxoid,
meningococcal vaccine, ...
*All lab. safety procedures & guidelines should be written and
available to all staff.
*Material safety data sheets (MSDS) for all chemicals and
microorganisms must be available.
•Lab. Personnel must receive proper training and orientation.
*Staff members should know the location of emergency
equipment & routes for evacuation in case of fire or accidents.
