Microbiological laboratories, and procedures involving micro-organisms in general laboratories, pose special safety problems, so the following policy and procedures must be followed rigorously.
In addition to those safety challenges commonly encountered in chemical laboratories, procedures undertaken in microbiological laboratories - indeed all procedures involving micro-organisms regardless of laboratory type - pose particular safety problems. Pathogens must be handled with great care in order to avoid infection of staff, the general public and animals outside the laboratory.
Microbiological hazards are particularly insidious because of the microscopic size of the organism.
The safest procedure is to regard all micro-organisms as potential pathogens and treat them accordingly.
Infection can result from ingestion, inhalation or skin penetration. In particular, staff or students having little or no microbiological training should not be exposed to situations in which they may not appreciate the potential hazards.
Non-laboratory workers such as cleaners and tradesmen should be given special instruction if they are to come into contact with this class of hazard. No one should be working in a microbiological environment without knowledge of recommended practices and procedures.
Prevention of cross-contamination or contamination with adventitious micro-organisms is important since this may nullify experimental procedures and lead to erroneous results. Such a situation may result in incorrect treatment of patients or modified techniques.
A biological hazard must be clearly indicated by standard biological warning signs giving the type and degree of risk and the person responsible. Immediately adjacent to the symbol, a sign shall also be displayed stating: Danger - infectious material.
Separate areas should be set aside for:
Animal rooms must be segregated from laboratories and should contain separate areas for infected animals, for non-infected animals and post-mortems.
Details: Australian Standard AS2243.3. Safety in Laboratories Part 3 – Microbiology. See the Standards Australia website.
Clean workstations, using biological safety cabinets or laminar flow clean air benches, are to be used for product and/or user protection. These types of equipment have different purposes and laboratory staff should be aware of the differences.
Laminar flow clean air benches protect the work (not the workers) from contamination and the air passes unfiltered onto the worker and into the laboratory. Laminar flow benches must never be used when handling pathogenic materials as any aerosols formed will be directed at the worker.
Virulent pathogenic organisms must be handled in a biosafety cabinet where contaminated air is passed through a high efficiency particulate air (HEPA) filter. There are three types of biological safety cabinet, Class I, Class II and Class III:
Class I and II cabinets are completely free-standing and must not be directly connected to ducting which has outside vents as wind may interfere with operator protection.
Any procedure, such as using blenders, shakers or sonicators, that is likely to produce infectious aerosols should be carried out in a biosafety cabinet.
Details of the construction and performance requirements: Australian Standard AS2252 – 1985, Biological Safety Cabinets Parts 1,2, and 3. See the Standards Australia website.
All biological cabinets must be inspected and maintained by a registered repairer every 12 months.
Whenever possible, decontamination should be achieved by sterilisation in an autoclave (steam heat under pressure). Disinfectants should only be utilised where sterilisation is not possible, for example, in large spaces, surfaces and delicate instruments. Disinfectants should be chosen on their effectiveness to deal with the specific type of micro-organism.
The main uses for disinfectants are:
The following are some commonly used disinfectants:
Steam heat autoclaves are used for sterilisation. Only properly trained staff should use the autoclave and care must be taken to ensure the load reaches the required temperature and remains at that temperature for the prescribed time.
Visual indicators such as Browne's tubes or heat-sensitive autoclave tape should be used routinely. Monthly checks of sterilising efficiency should be carried out by using spore strips, and times for sterilisation must be determined according to the load. Minimum sterilisation times after attainment of the required temperature are:
The standard reference book on this topic is Introduction to Sterilisation and Disinfection by J Gardner and M Peel, Churchill Livingstone (1986).
Animals can be an important source of infection which may be acquired by man via ingestion, inhalation, eye contact, skin lesions or bites.
Other than the general safety procedures already given, the basic principle to be observed in procedures requiring the use of animals is that handlers should be properly trained and/or supervised to minimise the risk of accidental injury or infection.
All animal users should be aware of the procedures governing the housing and care of animals in the University animal house areas. A copy of these procedures may be obtained from the Animal Welfare Officer on (+61 8) 6488 7882.
All infectious wastes should be disposed of in accordance with both federal and state regulations, and the following procedures should be followed:
Researchers who wish to carry out experiments which involve recombinant DNA techniques for the production of material incorporating recombinant DNA molecules unlikely to occur in nature must submit a proposal giving details of the project to the UWA Institutional Biosafety Committee (IBC) for approval.
The Gene Technology Act 2000 and Regulations have been produced to eliminate any possible hazard for occupational, public health and for the environment which may be associated with any genetic manipulation (GM) techniques. The safety of recombinant DNA work ultimately depends on the individuals conducting it.
The Biosafety Committee is available to provide advice to proponents about the Gene Technology Act 2000 and regulations. In particular it reviews applications for experiments as set out in the appropriate schedule of the regulations.
The committee serves a number of purposes such as:
Currently the Committee and UWA Safety and Health play a broad role on behalf of UWA:
There are three levels of physical containment for laboratory work with recombinant DNA. The classification is dependent upon the nature of the technique. The levels are referred to as PC 2, PC 3 and PC 4, with PC 4 being the highest level of containment.
Irrespective of the level recommended, there are certain practices that are minimum requirements for all levels.
Constant Temperature Rooms may be certified as PC2 facilities even if they do not contain sinks or coat hooks. Work shall otherwise follow the procedures required of PC 2 facilities.
In addition to the requirements for PC 2 level:
The requirements for a PC 4 laboratory are much more stringent than for other containment facilities, and the following are the requirements in addition to those for PC 2 and PC 3 levels.
The fire brigade may be called to fires in a PC 2 or PC 3 laboratory. For PC 4 facilities, procedures should be agreed in advance with the fire brigade.