eazyplex SuperBug kits for detecting carbapenemase-producing organisms

The innovation

CPOs are typically detected using microbiological culturing techniques which can take between 24 and 48 hours to give a result. Culturing techniques cannot usually differentiate between different carbapenemases and ESBL types.

The eazyplex SuperBug kits and the Genie II platform are molecular diagnostic systems, which use LAMP to detect and identify carbapenemase- and selected ESBL-encoding genes in rectal swab samples within 30 minutes. They would give results faster than the first stage of standard microbiological culturing used to identify CPO colonisation and would also provide more information about the type of carbapenemase present.

Current NHS pathway or current care pathway

People known to have been colonised before, or who are at risk of colonisation with CPOs, are routinely tested during hospital admission. If they test positive, they should immediately be isolated according to the Public Health England Acute Trust Toolkit (Public Health England 2013). Some hospitals may also test patient groups for organisms beyond those covered in the toolkit.

The Acute Trust Toolkit recommends testing 3 stool samples or rectal swabs collected on days 0, 2 and 4 after admission (Public Health England 2013). However, guidelines from a joint working party on the prevention and control of multi-drug-resistant Gram-negative bacteria recommend a single screening swab on admission (Wilson et al. 2016).

The samples are often tested for CPO colonisation by microbiological culturing using a selective (chromogenic) medium. This process of culture and incubation and getting a result typically takes 24 hours for positive samples and 48 hours for negative samples. If any CPO colonies are detected, additional tests are needed to determine the type of carbapenem resistance (Public Health England 2013). This would involve antimicrobial susceptibility testing using microbiological agar plates and an indicator carbapenem. If a sample is considered resistant to the carbapenem, further supplementary tests are done to distinguish carbapenemase producers from those that have other carbapenem-resistance mechanisms. Confirmatory tests can be inhibitor-based in which synergy can be shown between the indicator carbapenem and various carbapenemase inhibitors. Other methods include the modified Hodge test, the Carba-NP test (bioMerieux, US) or polymerase chain reaction (PCR)-based assays (Public Health England 2016).

The following samples should also be sent to the Reference Laboratory at Public Health England for further testing, to assess outbreaks:

The eazyplex SuperBug kits would be used in place of standard culture-based tests to determine the presence or absence of CPOs, although supplementary and confirmatory tests such as antimicrobial-resistance testing may still be needed for CPO-positive samples. Using these kits could result in a quicker diagnosis of CPO colonisation (in rectal swabs) or infection (from other specimen types) and allow healthcare providers to implement local infection control protocols to prevent transmission to other susceptible people. This could also allow CPO carriage to be more quickly excluded, so that people do not have to wait so long to be released from isolation.

NICE is aware of the following CE‑marked devices that fulfil a similar function as the eazyplex SuperBug kits:

NICE has also published a medtech innovation briefing on the Xpert Carba-R test.

Population, setting and intended user

The eazyplex SuperBug kits would be used on rectal swab samples from people who are at high risk of, or who are suspected of, colonisation with CPOs. The SuperBug CRE kit can also be used with other specimen types. They would be used in secondary or tertiary care clinical laboratories and run by qualified laboratory staff with appropriate training on the test and system.

Costs

Resource consequences

Individual eazyplex SuperBug kits and the Genie II system are considerably more expensive than current microbiological culture techniques and would therefore represent an additional acquisition cost to the NHS. There will also be costs associated with maintenance, training and quality assurance.

However, the faster turnaround time and greater level of information provided could lead to more efficient use of isolation resources by excluding CPO carriage quicker, therefore avoiding prolonged time in isolation. Quicker detection of CPO carriage may also result in faster infection control implementation and more appropriate antimicrobial therapy. Four specialist commentators advised that limited training would be needed and 1 suggested that the technology could be used in the laboratory by staff from any discipline or grade.