Zoonotic and antibiotic-resistant Campylobacter: a view through the One Health lens

Abstract

As a pathogen of a major public health concern with animal health importance, Campylobacter constitutes a clear and present threat to One Health. This organism colonizes the intestinal tract and is widely distributed among various animal species, including livestock and poultry, companion animals, and wildlife. As a result of its broad distribution, Campylobacter is exposed to antibiotics used in both human and veterinary medicine, which creates antibiotic selection pressure that has driven the development and rising prevalence of antibiotic resistant Campylobacter. This is particularly evident with the resistance to fluoroquinolone (FQ), which has become a great concern for public health. However, the increased prevalence of antibiotic-resistant Campylobacter cannot be solely attributed to antibiotic usage, as interspecies transmission and subsequent clonal expansion also contribute to the dissemination of antibiotic-resistant Campylobacter. This is exemplified by the emergence and expansion of FQ-resistant Campylobacter clones in animal production systems where FQ antibiotics were never used, the transmission of extensively drug resistant Campylobacter from dogs to human patients, and the spread of antibiotic-resistant and hypervirulent Campylobacter from ruminants to humans. Another notable finding from recently published work is the emergence of antibiotic resistance genes of Gram-positive origin in Campylobacter, suggesting that genetic exchange between Campylobacter and Gram-positive bacteria occurs in the natural environment and is more frequent than previously realized. Once these “foreign” antibiotic resistance genes are presented in Campylobacter, they can further disseminate by clonal expansion or horizontal gene transfer among different Campylobacter species/strains. These findings indicate that the emergence and transmission of antibiotic-resistant Campylobacter in the ecosystem are complex and multidirectional, and are affected by multiple factors. Thus, a holistic and One Health approach is necessary to fully comprehend and mitigate antibiotic resistant Campylobacter.