SCCmec type and epidemiological characteristics of MRSA isolates in the Netherlands

Abstract number: 1733_1073

Van den Broek I., Huijsdens X., Tiemersma E., van Loo I., Kluytmans J.

Objectives: To investigate the development of SCCmec types of Methicillin Resistant Staphylococcus aureus (MRSA) in the Netherlands in relation to epidemiological characteristics.

Methods: 76 MRSA isolates were randomly selected from the national MRSA database at the National Institute for Public Health and the Environment, in the period January 2003 to September 2005. We compared the epidemiological characteristics of the SCCmec types I, II and III (`Hospital Acquired') with types IV and V (`Community Acquired'). Patient information was provided by the referring hospitals.

MRSA isolates from the Netherlands, 2003–2006.

Results: Of the 76 isolates, 43 could be typed by SCCmec and 17 of these had the `HA'-type (4 I, 7 II and 6 III) whereas 26 had the `CA'-type (21 IV and 5 V). The development of these two groups over the years is shown in the figure. Of the HA-type isolates 82% were attributable to healthcare exposure while this was the case for only 35% of CA-type isolates; the first were more likely to originate from patients who had been admitted to a foreign hospital than the latter (65% versus 12%, p < 0.01). HA-isolates were found by intentional MRSA screening more frequently than CA-isolates (88% vs 42%, p < 0.01). CA-type isolates were more often associated with clinical signs of MRSA infection than HA-type isolates (46% vs 18%, p = 0.1), most of which were skin infections (92% vs 100%, ns). The living circumstances (degree of urbanisation) and occupation of the patient had no clear link to SCCmec type, though CA-type isolates more frequently originated from jobless persons than HA-type isolates (39% vs 18%).

Conclusion: The increase of MRSA in the Netherlands seems to be attributable to the CA-type isolates. The HA-type isolates are mainly derived from patients who have been hospitalised abroad and found by intentional screening. The majority of CA-types cannot be related to the healthcare setting and are coincidental findings indicating that the patients were not considered to be at increased risk. Further studies are warranted to identify the patients at risk for CA-MRSA.