**1. Introduction**

Modern medicine is a tributary to a continuously increasing degree of diagnostic and therapeutic invasiveness. In particular, intensive care units (ICUs) are confronted with increasing number of patients with marked co-morbidities, severe acute pathology or immune suppression, and intrinsic infectious risk factors. Additionally, given the pathogenicity changes of potentially hospital-acquired pathogens, most healthcare-associated infections (HCAIs) are caused by multidrug-resistant organisms (MDRO).

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
