First outbreak of MRSA ST398 in a Dutch hospital

Abstract number: P1452

Wulf M.W.H., Markestein A., van der Linden F.T.P.M., Voss A., Klaassen C.H.W., Verduin C.M.

Background: In the Netherlands the rate of Meticillin resistant Staphylococcus aureus infections in hospitals is still low, but community acquired MRSA occurs more frequently. This increase is mainly caused by so called `non-typable' MRSA (NT-MRSA, = not typable by PFGE using Sma1) belonging to MLST type ST398. This strain is widely disseminated among pigs, veal calves and people in contact with pigs. Transmission within families as well as solitary cases of colonised healthcare workers have been described but until now no nosocomial transmission to multiple patients or HCWs had occurred.

Outbreak: In June 2007 MRSA was isolated from a diabetic foot ulcer of a patient on a surgical ward. Subsequent screening of contacts among patients and healthcare workers revealed four additional patients with MRSA colonisation and/or infection and five HCW who carried MRSA. All strains were resistant to tetracycline and non-typable by PFGE. Spa typing showed that all strains to be t567, a type previously found in pigs. None of the patients had contact with pigs and/or veal calves. One healthcare worker lived on a pig farm but neither she nor her partner came into contact with pigs.

Conclusions: We describe the first outbreak of NT-MRSA among patients and HCW on a surgical ward. While the source is not fully established it could be the HCW living on a pig farm. This outbreak makes clear that transmission on a larger scale can occur, even with NT-MRSA.