Following the identification of an index patient with meticillin-resistant Staphylococcus aureus (MRSA) in a Dutch nursing home with 175 residents in the south of Limburg province, the Netherlands (microbiological diagnosis obtained from a foreign laboratory), a survey was carried out to trace contacts by means of the ‘ring principle’ of outbreak management. If positive cultures were found in the first ring of residents the contact and source tracing was extended. According to the Dutch guidelines for MRSA in nursing homes many preventive measures were taken regarding colonised residents and employees and the cleaning of rooms. Ten days after the occurrence of the index, 29 persons, 9 employees and 20 residents, were diagnosed as colonised with MRSA. Because of this extraordinary count compared with earlier Dutch findings (only 0.16 of inhabitants colonised) there were doubts about the laboratory results. A counter expertise from a Dutch lab and the National Institute of Health and Environmental Hygiene showed no MRSA, but meticillin-sensitive S. aureus.
This alleged epidemic had very aggravating consequences for residents and employees and large financial consequences for the nursing home. There was a good reaction to the crisis by a multidisciplinary team with external specialists. The Inspectorate of Health emphasized the importance of standardized quality and interpretation of laboratory results by microbiological experts. This should be kept in mind when contracting foreign laboratories specially because the Dutch policy is to strictly avoid MRSA in intramural setting. Verification of diagnosis proved again to be an essential step in outbreak management.