Introductory chapter

Abstract

Resistance to antimicrobial agents has been known since the beginning of the antibiotic era. In fact, Alexander Fleming and Selman Waksman were already aware of the ability of bacteria to become resistant to antibiotics. In addition, it is likely that this antibiotic resistance has been enhanced and stimulated by the extensive use of antimicrobials in human and veterinary medicine, as well as by the somewhat illicit use of these compounds in intensive livestock feeding. In anyway, the emergence of antibiotic-resistant bacteria currently constitutes one of the major problems facing medicine, in such a way that, in some cases, we are almost out of drugs to combat infection. Indeed, respiratory tract infections caused by multiresistant Pseudomonas aeruginosa, as well as infections caused by methicillin-resistant Staphylococcus aureus, are notoriously hard to control. In addition, some microbes are naturally resistant to most antimicrobials. This is the case for mycobacteria, as these organisms have a very hydrophobic lipid layer on their external surface that prevents hydrophilic drugs from entering the cell. In summary, the prevalent scenario is defined by a diminishing effectiveness of conventional antimicrobials, an increasing virulence of pathogenic and opportunistic microbes and the need to explore alternatives. Both the WHO 2014 Antimicrobial Resistance Global Report and the 2014 US Presidential Report emphasized the need to address this antimicrobial resistance (AMR) problem; and AMR was also the subject of the special actions initiated in the USA and Europe (IMI).