Volatile markets and constantly changing business conditions force manufacturing enterprises to continuously adapt their digital factory information systems. In many industries there is still no backbone for the integration of factory information systems. Current integration is based on point-to-point interfaces, which is partially due to the cost of replacing their established legacy systems. Furthermore the lack of flexibility prevents business processes to improve their responsiveness and adapt workflows of manufacturing to different turbulences. The principles of Service-Oriented Architecture (SOA) and its associated technologies (e. g., Enterprise Service Bus) and standards are key enabler and driver of the required flexibility. The presented Manufacturing Service Bus is a SOA-based approach that extends the Enterprise Service Bus capabilities in three areas: event management, factory context semantics and change propagation workflows. The Manufacturing Service Bus provides an event-driven platform for flexible integration of digital factory applications.