The first test of penicillin on a human, Constable Albert Alexander in 1941, illustrated the remarkable power of antibiotics to control bacterial infection, only to end in tragedy when all available penicillin was exhausted and Alexander’s infection recrudesced (McKenna, 2010). Since then, antibiotics have saved millions of lives and, due to their efficacy, their use has become ubiquitous in human and veterinary medicine. Unfortunately, any use of antibiotics, whether defined as prudent or not, will inevitably invoke Darwinian selection that favors the emergence, amplification, and persistence of antibiotic resistance. Thus, while Constable Alexander’s death resulted from an insufficient supply of antibiotics, the threat today is the lack of effective antibiotics due to widespread resistance. During the past 70 years, the health impact of antibiotic resistance has been held at bay primarily by the continual development of new classes of antibiotics and by new generations of existing classes. As has been widely reported, however, there are a number of issues limiting the pipeline of new antibiotics needed to continue to stay ahead of widespread resistance (Spellberg et al., 2008). A recent review identified 20 new antibiotic compounds in development since 2000, of which 8 out of 9 synthetic compounds are derived from quinolones—a class of antibiotic that may only require minor chromosomal mutations to gain resistance (Butler and Cooper, 2011).
Exacerbating the lack of new antibiotic classes to combat antibiotic resistance is an unprecedented increase in the ability of microbes to move around the world. Global travel aids the rapid spread of emerging pathogens and the expansion of pandemics (Tatem et al., 2006). Enteric bacteria carrying plasmid-encoded resistance to multiple antibiotics are carried surreptitiously, like Trojan Horses, connecting even remote communities to tertiary-care hospitals in a global network. Movement of people, however, is not the only means of spread, because resistance is also carried by microbes present in food and on fomites. The statement that any pathogen can move around the globe within 24 hours also holds for the spread of antibiotic resistance. In fact, the dissemination of antibiotic-resistance traits through travel and trade likely occurs at levels orders of magnitude higher than pathogens (Okeke and Edelman, 2001). There is no question that the emergence and maintenance of antibiotic resistance anywhere is a threat to health everywhere.