ABSTRACT
Prior to the use of antibiotics, bacterial infections were a major cause of morbidity and mortality in humans and animals. Diseases like diarrhea, diphtheria, pneumonia and tuberculosis were considered to be practically incurable (Zaffi ri et al. 2012). The discovery of penicillin by Alexander Fleming in 1928 (Fleming 2001) and its clinical use during the 1940s is considered to be one of the most important breakthroughs in the history of medicine and veterinary science (Zaffi ri et al. 2012). With the introduction of antibiotics, bacterial infection as a cause of death was addressed effi ciently, ultimately resulting in the expansion of human life expectancy. Since then, numerous antibiotics were discovered and used. Interestingly, the majority of these compounds derived from microorganisms. For a long time, antibiotics seemed to be the ultimate solution; however, bacteria started developing resistance to antibiotics mostly due to their overuse in human therapy as well as in livestock profi laxis (Neu 1992, Levy 2005, Mathew et al. 2007).
