This paper describes the building of an HL7-based Information Model Ontology (IMO) that can be exploited by a domain ontology in order to distribute querying over different clinical data repositories. We employed the Open Medical Development Framework (OMDF) based on a model driven development methodology. OMDF provides model transformation features to build an HL7-based information model that covers the conceptual scope of a target project. The resulting IMO is used to mediate between ontologically queries and information retrieval from semantically less defined Hospital Information Systems (HIS). In the context of the DebugIT project - which scope corresponds to the control of infectious diseases and antimicrobial resistances – Information Model Ontology is integrated to the DebugIT domain ontology in order to express queries.