Epidemiology of resistance to quinolones in Salmonella

Fluoroquinolones account for about 11% of antimicrobial prescriptions in human medicine worldwide and represent the drug of choice for the treatment of a wide range of human infectious diseases. They were introduced into veterinary medicine in Europe in the late 1980s and early 1990s and in the USA in 1995. Following their introduction, resistant strains of bacteria, including Salmonella, started to emerge. Resistance to quinolones depends on chromosomal mutations and the subsequent spread of resistant clones. While the selective pressure caused by the use of quinolones facilitates their epidemic transmission, the resistant mutants may spread independently of quinolone use. In view of the key role of this group of antimicrobials in human medicine and the position of Salmonella as the leading cause of food-borne infections in many countries, the public health hazard posed by quinolone-resistant zoonotic Salmonella serovars has been a subject of concern. The fluoroquinolones are on the WHO list of drugs that should be reserved for human use. Considering the mounting evidence that quinolone-resistant zoonotic Salmonella are the cause of severe, sometimes fatal, infections in humans, the use of fluoroquinolones in food animals should be discontinued or severely restricted. Such an intervention should be accompanied by prudent use measures involving all other groups of antimicrobials to reduce the need for fluoroquinolones in veterinary medicine.