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Working at Containment Level Three

NCTC holds a collection of approximately 700 restricted pathogens. These include Advisory Committee on Dangerous Pathogens (ACDP) hazard group three bacteria, animal pathogens, and hazard group two organisms that pose a greater risk to the operator during the manufacturing process. NCTC must abide by the relevant legislation when processing, storing, or shipping these strains.

In the UK, the Health and Safety Executive (HSE) defines hazard group three pathogens as those that “can cause severe human disease and may be a serious hazard to employees; it may spread to the community, but there is usually effective prophylaxis or treatment available.”

The restricted NCTC strains are handled in an ACDP Containment Level Three laboratory, which complies with UK regulations in both the design and management of the facility. The laboratory is equipped with engineering control measures to contain pathogens and create a safe working environment, such as microbiological safety cabinets, negative pressure, an autoclave, and full sealablity to allow for fumigation. Staff working in the facility are highly-skilled, performing daily safety checks, completing the required documentation, and diligently handing the pathogens in a safe manner.

Hazard Group Three pathogens in the NCTC Collection include: -

  • Shiga toxin-producing Escherichia coli such as NCTC 13733, isolated from human faeces and contains both stx1 and stx2 toxin genes.

  • Mycobacterium tuberculosis complex clinical isolates such as NCTC 13852 – NCTC 13859 that have been whole-genome sequenced by Casali et al (2012) to determine lineages in drug resistance.

  • Francisella tularensis subsp. holartica NCTC 10857, deposited in 1972 and used in the development of a live tularaemia vaccine.

  • Veterinary pathogens including 58 Brucella species, such as NCTC 7471 isolated in 1948 from milk in the UK.

In 2022, NCTC will be continuing the curation of the restricted pathogen collection in the containment level three facility.


Written by Hannah McGregor

December 2023