Novel or rare antimicrobial resistant organism (NRAO)

Clinical criteria
not relevant for surveillance purposes.

Laboratory criteria
The identification of an organism from any specimen, whether a diagnostic (invasive, non-invasive infection or colonisation, also known as carriage) or a screening specimen (colonisation, also known as carriage), with a confirmed pattern of antimicrobial resistance of clinical concern and not previously reported (novel) or rarely reported in Ireland.

For this purpose “clinical concern” means that the pattern of resistance is likely to impact on efficacy of antimicrobial agents that would normally be used to treat the species in question. The “confirmed pattern of antimicrobial resistance” should always be confirmed in a second laboratory (generally a reference laboratory). Guidance on what constitutes a NRAO should be sought from the relevant reference laboratory and the Health Protection Surveillance Centre.

Epidemiological criteria
Not relevant for surveillance purposes.

Case classification
- Possible case: Not applicable
- Probable case: Not applicable
- Confirmed case: Any person meeting the laboratory criteria

An outbreak of a novel or rare antimicrobial resistant organism is defined as two or more confirmed cases of the same antimicrobial resistance pattern (causing any of invasive or non-invasive infection or colonisation) that are linked epidemiologically in time and place.

Note: Given that chains of transmission of organisms are generally silent, assessment of linkage may be challenging. Guidance on what constitutes a NRAO and an outbreak of a NRAO should be sought from the relevant reference laboratory, the Health Protection Surveillance Centre and local Department of Public Health. If deemed indicated, an outbreak control team should be convened.

Current as of: 5 February 2019