To study a rapid Xpert polymerase chain reaction (PCR) method in detecting methicillin-resistant Staphylococcus aureus (MRSA) in patients and healthcare workers (HCW) exposed to MRSA, and to estimate savings associated to isolation or work restriction.

A test set of four double (one for the growth and one for the rapid test) pre-wet swabs from the nose, throat, hands/wrists and perineum was studied by a growth method and by the Xpert MRSA test.

The total correspondence between the growth and the rapid test was 92.8%. The overall sensitivity, specificity, positive and negative predictive values were for the Xpert MRSA test: 87%, 99.6%, 68.5% and 99.9%, and for the growth test: 76%, 100%, 100%, and 99.8%, assuming a prevalence of MRSA of 0.01%. Among the MRSA positive persons, the Xpert and growth tests detected MRSA in 44.6% and 40% of nose samples, respectively, 38.2% and 45.5% throat samples, 30.8% and 11.5% hands/wrists samples, 44% and 38% perineum samples, and in 81.8% and 77.3% wound samples, respectively. By combining four anatomical sites, the detection rate increased to 87.5% by both methods. The cost for each Xpert and growth test was €50 and €6.25, respectively. The rapid test would save at least €925 per exposed HCW and €550 per patient that were MRSA negative.

The MRSA Xpert test is easy to perform, has a high negative predictive value, and may be used to control healthcare workers and patients exposed to MRSA. Sampling from multiple anatomical locations is recommended. Still, more then 10% of MRSA positive cases may not be found.