School of Infection & Immunity

Biological Hazards

You should ensure that you know the categorisation of the organism(s) being used, and follow the appropriate recommendations given by the Scientific Advisory Committee for Genetic Modification (SACGM). The documentation 'Approved List of Biological Agents' is currently available in printed format from Helen Arthur. Note that no organisms in hazard group 4 should ever be received in this Centre. The organisms in hazard group 3 require special precautions. Anyone wishing to import HG 3 organisms must seek permission from the Head of Institute.

Particular care should be exercised when handling material of human origin and any member of staff responsible for bringing such material into the building must ensure that it has been adequately screened (especially for HIV and hepatitis B, C & D viruses) before its arrival in the building wherever feasible. Appropriate records of such material must be maintained. Staff working with such materials should be familiar with the recommendations contained in the HSAC and ACDP guidance documents:

• Safe working and the prevention of infection in clinical laboratories and similar facilities (2003);
• Revised Advice on laboratory containment measures for work with tissue samples (2001);
• Supplement to above Revised Advice for Work in Clinical Cytogenetic Laboratories; Protection against blood borne infections in the workplace - HIV & Hepatitis;TSE Agents: Safe Working and the Prevention of Infection
• : Managing the risks in laboratories and healthcare facilities, Health & Safety Executive
• Anti-Terrorism, Crime and Security Act (2001) list of Schedule 5 Pathogens and Toxins.

 

Handling of Cultures

Before starting work, you must:-

• read the relevant COSHH assessment and ensure that you know the categorisation of the organism(s) being used.
• assess the microbiological hazards under COSHH  and SACGM as appropriate.
• ensure that supplies of an appropriate disinfectant (eg 1% chloros or Virkon) are available.

 

On finishing or interrupting work, you must:-

• Never leave contaminated material unattended unless it is sealed and clearly labelled.
• On leaving the laboratory, swab benches and worktops

The safe handling of microbial cultures requires manipulative skill and so anyone intending to handle cultures must obtain advice from a member of their Department experienced in dealing with micro-organisms. In addition, the following points must be noted:- Wire loops should not be over-charged with liquid when flamed; the loop may 'spit' if heavily charged and the material which flies off is not necessarily sterile.

Cultures of micro-organisms must not be pipetted by mouth. Use a propipette. Contaminated pipettes must not be laid on the bench, but released tip downwards into a jar of disinfectant (0.25% chloros) and completely immersed. Contaminated Pasteur pipettes and slides should also be totally immersed in a (separate) plastic jar (eg Jencons Sharp-Safe) of disinfectant; after disinfection, the jar should be drained, capped and incinerated. Syringe needles must be disposed of in a CinBin.

Accidents with Biological Hazards

• All spillages must be reported using an Injury or Dangerous Occurrence form even when no personal injury is involved.
• If hands become contaminated, they should then be washed using a suitable disinfectant (eg 70% methylated spirit containing 0.5% Hibitane or a 1% solution of Savlon), before putting on disposable gloves in order to clean up. A contaminated laboratory coat must be removed to be autoclaved if practicable, or disinfected immediately and autoclaved later. A fresh laundered coat should be put on. Any contaminated personal clothing must also be removed and treated in the same way. 
•  If a tube, culture bottle, or flask is broken, the area should be flooded with disinfectant (e.g. 1% chloros or Hibitane 1/1000 or Virkon) immediately which should be allowed to act for 30-60 minutes after which the area should be cleaned up with water and allowed to dry. Broken glass should never be picked up with the fingers. Forceps or pan and brush should always be used and these should be disinfected after use. A wad of blu-tac or sticky tape may be useful to collect the smallest slivers.
• If bacterial cultures are spilt on the bench or floor, the nearest window must be opened and 10 minutes allowed for the for aerosol and droplets to disperse. Work must be stopped in the area and a warning noticed posted. The spilt material should then be mopped up with suitable disinfectant (e.g. Hibitane) which should be allowed to act for 3060 minutes, after which time the area should be cleaned up with water and allowed to dry. The hands should then be washed with a suitable skin disinfectant (e.g. Hibiscrub).

Opening of ampoules

Ampoules may be opened with the minimum of risk as follows:
The bottom of the ampoule should be held in several layers of tissue to protect the hands and a file mark made at about the level of the middle of the cotton wool plug which is inside the tube. A red hot glass rod or sealed Pasteur pipette should be applied to the mark. The glass will crack allowing air to enter the ampoule and equalise the pressures. After a few seconds the ampoule should be wrapped in a few layers of tissue or held in a small ball of plasticine and broken along the crack. The tissues and ampoule neck can then be discarded into disinfectant. About 0.5ml of medium is added to the ampoule, very slowly, drop by drop, with a Pasteur pipette to avoid blowing dried material out. The contents may then be mixed without bubbling and withdrawn into a culture tube.

Aerosols and droplets

Aerosols constitute a major infection hazard and may persist in the air for some time. Sources of aerosols and droplets include:-
• opening the screw-caps of universal containers
• opening of snap-on closures on plastic containers or plug stoppers
• rinsing pipettes when transferring dilutions etc.
• breakage of containers in centrifuges
• accidental breakages
• homogenising by mechanical means (particularly at high speeds)
• ultrasonic treatment
• operation of centrifuges

Guard against excessive production of aerosols by, for example, careful, non-violent pipetting. When pipettes are rinsed, e.g. between dilutions, or the contents are discharged into media or disinfectant, the tip of the pipette should be submerged and the contents expelled gently, without bubbling.

For Modifications of pathogens in ACDP hazard group 2 which involve risk of aerosol production, a  microbiological safety cabinet or equipment designed to contain the aerosol must be used.

Special Procedures

Anyone embarking on work involving the handling of pathogenic organisms/viruses for gene Modification should consult the appropriate member of staff and have your technique fully checked by that staff member before proceeding.

Microbiological Safety Cabinets must be serviced every 6 months. Additionally, a service operator protection test (KI-discus) test should be carried out once a year.