Clonal dissemination of epidemic methicillin-resistant Staphylococcus aureus in Belgium and neighboring countries

Objectives To determine the diversity of pulsed-field gel electrophoresis ( PFGE) types among epidemic strains of methicillin-resistant Staphylococcus aureus (MRSA) recovered in Belgium, France, Germany and The Netherlands ove r the period 1981-94. Methods MRSA strains collected in a multicenter survey in Belgium (n = 171) and from reference laboratories in neighboring countries (n = 102) were ch aracterized by PFGE analysis using the Smal enzyme. Results In total, 32 PFGE types were found. Epidemic PFGE type 1, first rec ognized in 1984, accounted for 82% of Belgian strains (87% of hospitals) an d 51% of European MRSA strains. Four other internationally epidemic PFGE ty pes (types 8, 10, 11 and 12) were less widely disseminated and more recentl y detected (1991-94), each recovered from two or three countries. Internati onal spread of two PFGE types was linked to transfer of colonized patients to Dutch hospitals from another country where this type was frequently reco vered. Conclusions Genotypic analysis indicated widespread distribution of several outbreak-associated MRSA strains over large European regions, which was in some instances related to interhospital patient transfer. These findings u nderscore the need for standardized international surveillance and control of MRSA transmission between healthcare institutions across Europe.