Pseudomonas aeruginosa is a waterborne bacterium that presents a significant, life-threatening risk to vulnerable populations within healthcare and hospital environments such as neo-nates, patients undergoing chemotherapy or organ transplants and the immunocompromised. The bacteria tend to build up as a biofilm in water systems at the ends of pipe systems and outlets, and although steps can be taken to design and maintain water systems to minimise biofilm growth, this is not always practical to do in older facilities. P. aeruginosa is most likely to be spread by direct contact with a tap or sink; if a contaminated patient or healthcare worker touches the tap, transmission can result.
UK Department of Health guidance on testing for P. aeruginosa is within Health Technical Memorandum 04-01 (HTM 04-01) Addendum: Pseudomonas aeruginosa – advice for augmented care units and suggests routine sampling and testing should be undertaken only in those areas of the hospital that have been designated as providing augmented care. Here, every outlet should be tested at a minimum frequency of every six months.
The consequences of a P. aeruginosa outbreak can be severe and has led to tragic, fatal incidents in the UK; however by monitoring the condition of water systems and instigating rapid remedial works, facilities managers can ensure that contamination does not lead to prolonged closure of wards which reduces the efficiency and capabilities of a hospital.
Pseudalert: Rapid identification of Pseudomonas aeruginosa
Launched by IDEXX in 2014 into the UK healthcare sector, the Pseudalert test facilitates rapid identification of P. aeruginosa in hospital water systems using an innovative bacterial enzyme technology. The test gives either a confirmed presence/absence or a quantified result in only 24 hours, which is less than half the time taken by traditional agar culture methods.
The test can either be carried out in a laboratory environment, or set up with minimal capital expenditure in-house, for testing and monitoring of water systems. Pseudalert is very sensitive and detects P. aeruginosa at levels as low as 1 colony forming unit, in standard 100 ml samples.
Pseudalert is simple to use, delivers definitive results with no additional confirmation steps, and minimises the risk of false positive results from non-target organisms.
Using Pseudalert, actively growing strains of P. aeruginosa have an enzyme that metabolises the substrate in the reagent to produce blue fluorescence under ultraviolet light.
Where quantification of a sample is required, the IDEXX Quanti-Tray®, which consists of 51 individually sealable cells, can also be incubated for 24 hours after which fluorescent cells can be counted and quantified by reference to a Most Probable Number table.
Regulatory acceptance of Pseudalert
In September 2018, Pseudalert became accepted as the worldwide standard ISO 16266-2, marking a significant milestone for IDEXX Water.
In the UK, it has been accepted by the UK Standing Committee of Analysts for the analysis of drinking water, and is specified as a recommended method in the Committee’s “Blue Book” publication, “The Microbiology of Drinking Water (MoDW) Part 8 – Methods for the isolation and enumeration of Aeromonas and Pseudomonas aeruginosa,” This means that Pseudalert meets the requirements specified by the Department of Health publication HTM04-01 and is therefore validated to be used to undertake the microbial examination of water samples for P. aeruginosa in a UK healthcare environment.
Pseudalert is also included in several European country-specific standards, and was shown to be as accurate as or more accurate than the traditional method in two independent studies.