WATER SYSTEMS
other water-associated opportunistic pathogens, non-tuberculous mycobacteria are present in the environment, and can proliferate in drinking water systems, attaching to a variety of surfaces, and establishing biofilms not too dissimilar to Pseudomonas aeruginosa and Legionella bacteria – which are among select bacteria able to enter, and survive within, amoebae. These properties confer the resistance needed to survive conventional water treatment, and proliferate in drinking water systems despite the presence of disinfectant residuals. Their resistance to chlorine has been recognised as key to the survival, colonisation, and persistence, of environmental mycobacteria in water distribution systems.
Generic variability
Identifying and quantifying NTM in environmental samples is complicated by genetic variability among species, making it challenging to determine if clinically relevant NTM are present. Sampling frequency should be agreed by the WSG and the IPC team. Analysis for Non-Tuberculosis Mycobacteria is normally covered within the Environmental Mycobacteria analysis (EM). The bacteria are principally transmitted by ingestion, inhalation, and inoculation from environmental sources, rather than person to person. A BBC News story last November highlighted a case of Mycobacterium abscessus – a group of rapidly growing bacteria of particular concern to lung transplant patients and other immunosuppressed individuals.5
This
Mycobacterium species is currently not monitored in healthcare, but this is something that needs addressing. Mycobacterium abscessus is a
bacterium distantly related to the ones that cause tuberculosis and Hansen’s Disease (Leprosy). Part of a group of environmental mycobacteria, it is found in water, soil, and dust, and has been known to contaminate medications and medical devices.
‘‘
Correct hand hygiene in healthcare must be strictly observed to slow down, if not eradicate, hazardous microorganisms. The COVID-19 pandemic highlighted its importance to everyone
Skin and soft tissue diseases M. abscessus can cause a variety of infections. HAIs caused by it are usually of the skin and the soft tissues underneath. It also causes serious lung infections in those with chronic lung diseases like cystic fibrosis.6
People with open
wounds, or who receive injections without appropriate skin disinfection, may also be at risk.
UKAS accreditation and choosing a laboratory Since water analysis provides vital information, it should be undertaken in accordance with current ISO standard methods. In the UK, laboratories and other organisations providing certification, testing, inspection, and calibration services, should be accredited by UKAS. Water sample analysis for Legionella should be performed in UKAS- accredited laboratories. The current ISO standard methods for the detection and enumeration of Legionella are included within the scope of accreditation to EN ISO 17025: General requirements for the competence of testing and calibration laboratories. The Health and Safety Executive
HSG 274 Technical guidance Part 2 recommends that these laboratories take part in a water microbiology proficiency testing scheme, such as that run by Public Health England (PHE), or an equivalent ISO 17043-accredited scheme. Alternative quantitative testing methods may be used if validated using ISO 17994: Water quality – Requirements for the comparison of the relative recovery of microorganisms by two quantitative
methods, and the tests meet the required sensitivity and specificity. This standard was last reviewed and confirmed in 2019, and is still current.
Standards writing for many different sectors The International Organization for Standardization (ISO)7
is the international
organisation that writes standards for many sectors, ISO 9001 and 14001 being among the best known. UKAS oversees the standards in the UK, assessing organisations including laboratories against recognised standards. Not all ISO standards require UKAS accreditation. ISO 9001 is a standard used for certification, rather than accreditation, and thus UKAS does not assess or provide accreditation to this standard. So, what is the difference between accreditation and certification?8
A written assurance Certification is a third party’s written assurance on the conformity of a service, product, or process, based on specified requirements provided by some form of education, audit, assessment, or external review. The third party provides certification by indicating full satisfaction with a service, product, or process. It is important to be certified by an official certification body. Accreditation refers to formal
recognition on the competency towards specified standards by an authoritative body like UKAS. These bodies also test and supervise organisations tasked with testing, calibrating, inspecting, and certifying, firms against internationally set standards.
Legionella pneumophila and Pseudomonas aeruginosa (pictured left and right) are present in the environment, and can proliferate in drinking water systems.
February 2023 Health Estate Journal 37
CDC
HansN., CC BY-SA 4.0, via Wikimedia Commons
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