Workpackage 1: Project IP4

Title of the project: LA-MRSA spread from food to consumers


Contact IP4

PD Dr. med. Alexander W. FriedrichDr. med. Robin Köck
Institute of Hospital Hygiene
Klinikum Oldenburg gGmbH
D-26133 Oldenburg

Phone +49 (0)441-403-2690
Fax +49 (0)441-403-2318
E-mail: robin.koeck[at]

Other Contactpersons:

PD Dr. med. Mellmann
Institute of Hygiene
University Hospital Münster
Phone +49 251-83-55690
Fax +49 251-83-55688
E-mail: alexander.mellmann[at]


Until now various epidemiological reports described a close risk-association between animal contact and colonization with MRSA CC398. However, our results from the first funding period indicated nosocomial transmission and a rising number of publications have revealed that the proportion of MRSA CC398 with unknown origin (i.e. no contact with livestock) has increased. We analyse this question in a prospective epidemiological study.

Phylogenetic models based on SNP analysis showed that MRSA CC398 originate from human methicillin-susceptible S. aureus (MSSA), that were transferred to livestock animals where they acquired methicillin- and tetracycline resistance., but lost an important virulence factor, the so-called immune evasion cluster (IEC) encoded on a β-haemolysin-converting phage (φ3). Hence, it was indicated by this model, that MRSA CC398 occurring among humans are mostly zoonotically transferred LA-MRSA CC398 which are less adapted to the human host (since they do not carry the IEC which is crucial to facilitate escaping the human immune response system). We analyse this hypothesis by performing whole genome sequencing of MRSA CC398 isolates from humans and livestock (derived in the same region).