National MRSA Reference Laboratory

Department in Depth

NMRSARL currently offers services including the confirmation of S. aureus identification and meticillin resistance, epidemiological typing, investigation of glycopeptide resistance and detection of virulence factors. The service is available to microbiology laboratory medical and scientific staff in hospitals in Ireland. Details in the user manual are described on this page but should you require a printed version it is available to download below.

Confirmation of meticillin resistance
Isolates giving equivocal results with the standard tests for species identification of S. aureus are tested by PCR to detect the species specific nuc gene. Isolates with borderline resistance to meticillin are tested by oxacillin E-tests and by PCR to detect the mecA gene.

Epidemiological typing
Using a combination of 27 antimicrobials and heavy metals all isolates are assigned an antibiogram- resistogram type. Using this method more than 90% of MRSA isolates are assigned to known epidemic strains. Genotyping by pulsed field gel electrophoresis (PFGE) typing and spa typing is carried out where appropriate. PFGE type of MSSA is also performed if required. PFGE is the more discriminatory technique and is particularly valuable in the investigation of localised outbreaks. Other sequence-based methods, e.g. MLST are carried out on selected isolates in conjunction with a collaborative laboratory.

Antibiotic susceptibility monitoring
AR typing using CLSI disk diffusion methodology allows NMRSARL monitor changing/ emerging resistance patterns in Irish MRSA. Isolates with reduced susceptibility to mupirocin are further tested by mupirocin E-test to distinguish between high and low level mupirocin resistance.

GISA (Glycopeptide intermediate resistant Staphylococcus aureus) screen
All referred isolates are screened for glycopeptide resistance using teicoplanin and vancomycin agar screening plates. Isolates positive on screening are tested by E-test against vancomycin and teicoplanin using a CLSI Macromethod and if required a modified population analysis profile is performed.

Part of NMRSARL’s current work is the routine monitoring of MRSA strains prevalent in Ireland. This is done in conjunction with the HPSC by epidemiological typing of MRSA isolates received from Irish hospitals that participate in the European Antimicrobial Resistance Surveillance Network (EARSNet). This information is used to monitor the changes in the MRSA population in Ireland.

Detection of Virulence Factors
PCR tests for the detection of the Panton-Valentine leucocidin (PVL), a virulence factor associated with MRSA and MSSA strains causing skin and soft tissue infection in the community is investigated in NMRSARL (for research purposes only).

Staphylococci other than MRSA
Many of the tests performed in the Reference Laboratory are useful in the investigation of other Staphylococci. Epidemiological typing of MSSA by PFGE and species identification of CNS by phenotypic methods will be undertaken on request.

Quality Policy
The Quality Management System of the NMRSARL ensures that we provide a prompt, quality assured and clinically appropriate service to users throughout Ireland. This is done through a process of quality planning which is the part of quality management focused on setting quality objectives and specifying necessary operational processes and related resources to fulfill quality objectives. Should you require details of the accreditation status of the NMRSARL please contact the laboratory directly.

Annual Reports
Reports on the work of the NMRSARL have been produced annually and distributed to all Consultant Microbiologist and Chief Medical Scientist. The current annual report is available in the Reference Material section below.

The staff of the NMRSARL has played an important role in the investigation of MRSA in Ireland. Since its establishment the staff of the NMRSARL have been involved in numerous collaborative research projects both nationally and internationally. A list publications involving staff of the NMRSARL is available in the Reference Material section below.section below.

Reference Material

Annual Report 2017 (PDF 1,266Kb)

Annual Report 2016 (PDF 2,091Kb)

Annual Report 2015 (PDF 2,375Kb)

Annual Report 2014 (PDF 1,456Kb)

Annual Report 2013 (PDF 2,501Kb)

Annual Report 2012 (PDF 1,843Kb)

Annual Report 2011 (PDF 2,156Kb)

Annual Report 2010 (PDF 619Kb)

Annual Report 2009 (PDF 638Kb)

EARS-Net MRSA Summary Report Q2, 2017 (PDF 511Kb)

Publications involving Staff of the NMRSARL (PDF 2,107Kb)