In addition, the overuse and misuse of antibiotics has led to the emergence of antibiotic-resistant bacteria, compromising the effectiveness of antimicrobial therapy because the infectious organisms are becoming resistant to commonly prescribed antibiotics. In fact, the emergence and spread of resistant bacteria have been classified by the World Health Organization (WHO) as one of the major threats to public health in the 21st century, and without urgent actions we are heading to a post-antibiotic era, in which common infections and minor injuries could eventually cause death.