Veterinary Public Health and Antimicrobial Resistance
The control and prevention of AMR has become a public health priority as reports of AMR emergence and spread increase from around the world. Veterinarians are medical professionals, and have a public health responsibility to ensure that antimicrobials are used appropriately and prudently to preserve the efficacy of antibiotics for both animals and humans. The bottom line is that we do not want our grandchildren to suffer the ill effects of antibiotic treatment failure because we squandered the efficacy of antibiotics when good alternative options were only slightly less convenient. Cost-benefit analysis of antimicrobial use policy must compare future costs if ANR to the present costs of using antibiotics more judiciously.
Animals, Humans and Antimicrobials.
Epidemiological and molecular observations have shown that AMR in animal populations can increase AMR problems among human populations. For example, vancomycin resistant enterococci (VRE) in both animals and people have become prevalent in countries that used a glycopeptide growth promotant called avoparcin, which is structurally similar to vancomycin. Vancomycin is a very important antibiotic in human medicine that is often used a last line of defense for several types of infectious agents. The banning of avoparcin’s use in animals was followed by a rapid subsequent decline in the incidence of VRE in both human and animal populations. However, VRE in Europe has not disappeared.
Genes encoding resistance to antibiotics used only for animals have been found in increasing prevalence among animal pathogens, in the commensal flora of humans, in zoonotic pathogens like Salmonella and in strictly human pathogens like Shigella. This indicates the clonal spread of resistant strains and the shared transfer of resistance genes among bacteria infecting both humans and animals.2
The introduction of enrofloxacin in veterinary medicine was quickly followed by the emergence of fluoroquinolone resistance among Campylobacter isolates from broilers, and in Campylobacter from humans shortly thereafter. As was the case with avoparcin, resistance to fluoroquinolones in human and animal populations remained rare in countries that had not used fluoroquinolones in food animals3
In yet another example, an increase in AMR to third-generation cephalosporins in Salmonella and E.coli was observed following the increased usage of these antibiotics in Canadian poulty. Furthermore, their withdrawal and re-introduction were subsequently followed by a decline and resurgence, respectively, in AMR among poultry and human Salmonella isolates.