Chapter I General safety rules in Microbiological Laboratory Flashcards
the application of safety precautions that reduce a laboratorian’s risk of exposure to a potentially infectious microbe and limit contamination of the work environment and, ultimately, the community.
Biosafety
Four biosafety levels
Biosafety level 1
Biosafety level 2
Biosafety level 3
Biosafety level 4
organisms are well-characterized strains of microorganisms
not known to cause disease in healthy human adults.
Biosafety level 1
organisms include in this biosafety level are non-pathogenic laboratory strains of Escherichia coli, Staphylococcus xylosus, and Bacillus megaterium.
Biosafety level 1
Organisms are moderate-risk microorganisms associated with less serious human diseases whose potential for transmission is limited and a proven treatment for the disease exists.
Biosafety level 2
pathogens are opportunistic, particularly in children and immunocompromised adults. Additional precautions in this biosafety level include using personal protective equipment (PPE) such as disposable gloves and laboratory coats and limiting lab access to trained individuals.
Biosafety level 2
Organisms are high-risk microorganisms with a true potential for infection by aerosols and in which the resulting disease may have serious or lethal consequences.
Biosafety level 3
organisms include Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella
Biosafety level 2
Researchers in this biosafety level generally wear double gloves, respirators, and disposable surgical scrubs and gowns, and work in biological safety cabinets in isolated, negative-pressure containment rooms.
Biosafety level 3
organisms include Mycobacterium tuberculosis, Foot-and-mouth disease virus, and Bacillus anthracis.
Biosafety level 3
organisms include Avian flu viris, Ebola virus, Marburg virus, and Lassa fever virus.
Biosafety level 2
organisms are easily transmitted, very-high risk microorganisms which cause life-threatening diseases for which there is no vaccine or therapy.
Biosafety level 4
Laboratories work in impermeable positive pressure “space suits” with an external oxygen supply, and precautions such as chemical showers must be taken before exiting the lab.
Biosafety
A very important biosafety practice. Incidents involving biological, chemical, physical, and radiological hazards can have a significant impact on the safety and health of those who work in laboratory settings.
Microbiological risk assessment
Steps of risk management
Step 1: Identify the hazard and risk
Step 2: Evaluate the risk
Step 3: Implement a risk mitigation plan, as needed
Step 4: Evaluate the effectiveness of controls
Ask what, where, and how the work is occurring and who is doing the work. Then, determine what could go wrong in every step of the activity or procedure and the result of the undesirable incident (e.g., injury, exposure, infection, disease).
Identification of the hazards and risks
Characterize the risks
Likelihood of the risk
Consequence of risk
Risk evaluation
Example; strictly implement proper disposal of waste (ie sharps)
Risk mitigation plan
How to conduct risk assessment?
- Identification of the hazards and risks
- Risk evaluation
- Risk mitigation plan:
- Evaluation of effectiveness of control
Example ; needle sticks or broken glass (slides, cover slips, beakers etc)
Characterize the risks
Example; absence of proper disposal of sharp objects
Likelihood of the risk
Example; cuts, or potential infection from exposure to biological
agents
Consequence of risk
Classification of infective microorganisms
- Risk Group 1 (no or low individual and community risk) 2. Risk Group 2 (moderate individual risk, low community risk)
- Risk Group 3 (high individual risk, low community risk)
- Risk Group 4 (high individual and community risk)
A microorganism that is unlikely to cause human or animal disease.
Risk Group 1 (no or low individual and community risk)
A pathogen that can cause human or animal disease but is unlikely to be a serious hazard to laboratory workers, the community, livestock or the environment. Laboratory exposures may cause serious infection, but effective treatment and preventive measures are available and the risk of spread of infection is limited.
Risk Group 2 (moderate individual risk, low community risk)
A pathogen that usually causes serious human or animal disease but does not ordinarily spread from one infected individual to another. Effective treatment and preventive measures are available.
Risk Group 3 (high individual risk, low community risk)
A pathogen that usually causes
serious human or animal disease and that can be readily transmitted from one individual to another, directly or indirectly. Effective treatment and preventive measures are not usually available.
Risk Group 4 (high individual and community risk)
an enclosed, ventilated laboratory workspace for safely working with materials contaminated with (or potentially contaminated with) pathogens requiring a defined biosafety level. It is intended to offer protection to the user and environment from the aerosol hazards arising from the handling of infected and other hazardous biological material.
biosafety cabinet (BSC)—also called a biological safety cabinet or microbiological
safety cabinet
types of safety cabinet
Class I
Class II
Class III
Safety cabinet with front opening through which the operator can carry out manipulations inside the cabinet and which is constructed so that the worker is protected and the escape of airborne particulate contamination generated within the cabinet is controlled by means of inward airflow through the working front opening and filtration of the exhaust air.
Class I BSC
safety cabinet with front opening through which the operator can carry out manipulations inside the cabinet and which is constructed so that the worker is protected, the risk of product and cross-contamination is low and the escape of airborne particulate contamination generated within the cabinet is controlled by means of an appropriate
filtered internal airflow and filtration of the exhaust air (laminar airflow).
Class II BSC
Safety cabinet in which the working area is totally enclosed and the operator is separated from the work by a physical barrier (I.e. gloves mechanically attached to the cabinet). Filtered air is continuously supplied to the cabinet and the exhaust air is treated to prevent release of micro-organisms.
Class III BCS
to examine microorganisms which can’t be seen by naked eyes
Microscope
to heat or boil solution in laboratory
Bunsen burner
What’s the function of Autoclave
to sterilize the equipment medias and other solutions
What’s the function of Pressure cooker
to sterilize the equipment medias and other solutions
to preserve the samples, media, reagents and other specimen
Refrigerator
a laboratory device that employs a rotating magnetic field to cause a stir bar (or flea) immersed in a liquid to spin very quickly, thus stirring it.
Magnetic Stirring Plate
used for bacterial or fungal cultures
Incubator
To rescue the exposure of the operator and the lab contamination
Safety Cabinet
(used to inoculate test samples into culture media for bacterial or fungal cultures, antibiograms, etc.)
Wire loop/inoculating loop
to act as a supporting container to hold the
culture medium
Petri dish
a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom.
Test tube
a piece of laboratory equipment designed to hold multiple test tubes upright at the same time.
Test tube rack
To measure and prepare media
Flask
To measure and transfer solution
Beaker
to measure the weight of an
specimen
Weighing scale
to transfer quantified volume of specimen or solution
Pipettor
Used to heat medium gently (to around 45-55℃) during media preparation
Water bath
essential tools in any laboratory setting, especially for precise liquid handling.
Pipette tips
thin, flat pieces of glass used to hold specimens for examination under a microscope.
Glass slides
thin, square pieces of glass placed over the specimen on the slide. They help flatten the specimen, protect it from contamination, and prevent the microscope’s objective lens from coming into direct contact with the specimen.
Cover slip
bottles in laboratories protect light-sensitive substances from UV and blue light, ensuring their stability and efficacy.
Amber bottles
for storage of media, regeants and other materials
Cupboards
securely organizes and protects PPE from contamination and damage, ensuring it is readily accessible and in good condition for use.
Storage cabinet for personal protective equipments
(PPE’s)
used to quickly and effectively put out small fires, preventing them from spreading and causing more damage.
Fire extinguisher
Use to differentiate bacterial species into gram-negative and gram-positive groups based on the chemical and physical properties of their cell wall.
Gram’s staining set
treatment of work surface before and after use and spillages; disposal of used pipettes and microscope slides; in soap form for hand washing
Disinfectant
sterilization of metal forceps
and glass spreaders by ignition
Denatured 70% Alcohol
dealing with spilled cultures
Spillage kit
may be taken from animals or the environment for a variety of purposes, such as disease diagnosis, disease surveillance, health certification or monitoring the response to treatment or vaccination. T
Samples
may be taken for haematology or for culture and/or direct examination for bacteria, viruses, or protozoa, in which case it is usual to use anticoagulants, such as ethylene diamine tetra-acetic acid (EDTA) or heparin
Blood samples
They may also be taken for serology, which requires a clotted sample (serum/plasma).
Blood samples
Ideally the skin at the site of venipuncture should first be shaved (plucked) and
swabbed with ____________ and allowed to dry.
70% alcohol
A blood sample is taken, as cleanly as possible, by ___________________ (not easy in delicate veins but
convenient in strong veins)
venipuncture with a syringe
and needle or by needle and vacuum tube
Site of blood sampling of large animals
via jugular vein or a caudal vein, or less commonly brachial veins and mammary veins
Site of blood sampling of Pigs
vena cava veins
Site of blood sampling of birds
a wing vein (brachial vein) is usually selected
For serum samples, the blood should be left to stand at ambient temperature (but protected from excessive heat or cold) for __________ until the clot begins to contract and placed in a refrigerator at ______ After several hours, or overnight, the sample can be centrifuged at about ____________________ and the serum can be decanted or removed with a pipette.
1–2 hours
4°C
1000 g for 10–15 minutes
useful for surface-feeding mites, lice and fungal infections
Plucked hair or wool samples
using the edge of a scalpel blade, are useful for burrowing mite
Deep skin scrapings
Samples may be taken by vaginal or preputial washing, or by the use of suitable swabs.
Genital tracts and semen sample
In birds, feather tips can be taken for detection of viral antigen where ________
disease is suspected.
Marek’s
The cervix or urethra may be sampled by
Swabbing
Best obtained using an artificial vagina or by extrusion of the penis and artificial stimulation.
Samples of semen
Samples of semen are best obtained using an artificial vagina or by extrusion of the penis and artificial stimulation. The ________________ should be present in the sample and contamination by antiseptic washing solutions should be avoided.
sperm-rich fraction
can be taken by holding the palpebra apart and
gently swabbing the surface. The swab is then put into transport medium.
Samples from conjunctiva
rapings may also be taken on to a microscope slide. The handles of metal- handled swabs are useful for this, to ensure that sufficient cells are removed for microscopic examination
Eye samples
rarely useful in eye samples
Mucopurulent nasal and lacrimal discharges
Samples may be taken with dacron, cotton or gauze swabs, preferably on wire handles as wood is inflexible and may snap. It may be helpful if the swab is first moistened
Nasal discharge (saliva)
Long protected _____________ should be used to collect samples for some suspected viral infections.
nasopharyngeal swabs
In nasal discharge sample, the swab should be allowed to remain in contact with the secretions for up to _________, then placed in transport medium and sent to the laboratory without delay at ____.
1 minute
4°C
should be taken after cleansing and drying the tip of the teat, the use of antiseptics should be avoided.
Milk samples
should be discarded and a tube filled with the next stream(s), a sample of bulk tank milk can
Initial stream of milk
Milk for _____________ should not have been frozen, heated or subjected to
violent shaking.
serological tests
If there is going to be a delay in submitting them to the laboratory, ____________can be added to milk samples that are being collected for
serological testing. If necessary, milk for bacterial examination can be frozen.
preservatives
Samples may be taken to monitor hygiene or as part
of a disease enquiry
Environmental and feed sampling
should be done by trained
Sample collection at post-mortem
commonly taken from litter or bedding and voided feces or urine
Environmental samples
wabs may be taken from the surface of ventilation ducts, feed troughs and drains. This kind of sampling is particularly important in ____________ in which specialised equipment
hatcheries, artificial insemination centers and slaughterhouses
Samples may also be taken from animal feed, in __________
troughs or bulk containers
may be sampled in troughs, drinkers, header tanks or from the natural or artificial supply
Water
It is essential that individual samples be clearly identified using appropriate methods. Marking instruments should be able to withstand the condition of use, i.e. being wet or frozen use ______________
indelible marking pen
Possibly the most useful collection is the storage of serum samples _____________. These samples may be useful if a retrospective investigation is carried out to compare the present disease status with that of earlier times.
serum banks
Information to be sent with samples
a) Name and address of owner, or sender and geolocation where disease occurred, with telephone and fax numbers.
b) Diseases suspected and tests requested.
c) The species, breed, sex, age and identity of the animals sampled.
d) Date samples were collected and submitted.
e) List of samples submitted with transport media used.
f) A complete history would be beneficial for the laboratory and should be included if possible.
Establishing a collection of samples for future studies can be very useful. This can include cultures for comparison with future isolates, tissue or serum samples that can be used for the validation of new tests and a collection of fixed tissues, or paraffin blocks, for future histological examination.
Preservation of samples for prolonged storage
