Given the increasing commercial and clinical relevance of probiotic cultures, improving their stress tolerance profile and ability to overcome the physiochemical defences of the host is an important biological goal. Pathogenic bacteria have evolved sophisticated, strategies to overcome host defences, interact with the immune system and modulate essential host systems. The 'Patho-biotechnology' concept promotes the exploitation of these valuable traits for the design of more technologically robust and effective probiotic cultures with potentially improved biotechnological and clinical applications, as well as the development of novel vaccine and drug delivery platforms. (c) 2007 Elsevier Ltd. All rights reserved.