CONCORD · CONtrol of COmmunity-acquired MRSA: Rationale and Development of counteractions

Until recently, methicillin-resistant Staphylococcus aureus (MRSA) were confined to hospitals (HA-MRSA). However, community- and farm-associated MRSA (CA-and FA-MRSA) has developed as an important cause of infections. No strategies exist to combat these MRSA. CONCORD is aimed at explaining the ecological success in the community and the farm environment of CA- and FA-MRSA in contrast to HA-MRSA in order to facilitate the rationale and development of effective strategies against CA- and FA-MRSA. Epidemiology of CA-MRSA is complex and incomplete. To obtain both a more complete description of the epidemiology of CA-MRSA and recent isolates small scale surveillance will be performed among patients in the 20 most populous EU countries, pig farms in major pig exporting countries and important veal calve raising countries. Genomics data for CA-MRSA are limited and non-existent for FA-MRSA. Successful adaptation of MRSA to a new environment supposes either the acquisition of novel properties or the differential expression of genes already present. Only 2 CA-MRSA have been fully sequenced and the UMCU has sequenced a FA-MRSA. Whole genome sequencing, comparative genome hybridization and transcriptomics will be used to understand the genetic adaptations of MRSA in the community. The contribution of putative virulence factors to pathogenicity will be studied by knock-outs and complemented strains of these knock-outs. The strains will be tested in in vitro and ex vivo models to establish their physiological role. Mathematical modelling is an important tool to manage infection control. A few models exist that evaluate measures to reduce transmission of HA-MRSA or CA-MRSA in jails. No models are available for FA-MRSA. Modelling will provide both fundamental insights on MRSA epidemiology as well as specific recommendations or testable hypotheses for human and veterinary clinical practice. The potential of intervention strategies to combat CA- and FA-MRSA will be determined.