Introduction: emerging antimicrobial resistance mechanisms in the zoonotic foodborne pathogens Salmonella and Campylobacter

摘要

Salmonella and Campylobacter are the most commonly reported bacterial causes of human foodborne infections, and increasing proportions of these pathogens have become resistant to medically important antimicrobial agents, imposing a burden on public health. Strains of Salmonella enterica with resistance to antimicrobial drugs are now widespread in both developed and developing countries. Since the early 1990s, multiresistant strains of S. enterica serovar Typhirnurium definitive phage type 104, displaying resistance to up to six commonly used antimicrobials, have gained particular importance. These strains harbour a chromosomally integrated genomic island called Salmonella genomic island 1 (SGI1) including a complex antibiotic resistance gene cluster, of which a number of variants have been described. SGI1 has spread to several S. enterica serovars, and it has been recently shown to be an integrative mobilizable element. Also of particular concern since the 2000s is the development of resistance to key antimicrobials such as fluoroquinolones, particularly in Asian countries, and also extended-spectrum cephalosporins worldwide. The use of newer p-lactams in animal husbandry and veterinary medicine may have facilitated the spread of extended-spectrum cephalosporin-resistant Salmonella strains in livestock.