β-lactam resistance in gram-negative pathogens isolated from animals.
Although β-lactams remain a cornerstone of veterinary therapeutics, only a restricted number are actually approved for use in food-producing livestock in comparison to companion animals and wildlife. Nevertheless, both registered and off-label use of third and fourth-generation cephalosporins in livestock may have influenced the emergence of plasmid-encoded AmpC β-lactamases (pAmpC) (mainly CMY-2) and CTX-M extended-spectrum β-lactamases (ESBLs) in both Gram-negative pathogens and commensals isolated from animals. This presents a public health concern due to the potential risk of transfer of β-lactam-resistant pathogens from livestock to humans through food. The recent detection of pAmpC and ESBLs in multidrug-resistant Enterobacteriaceae isolated from dogs has also confirmed the public health importance of β-lactam resistance in companion animals, though in this case, human-to-animal transmission may be equally as relevant as animal-to-human transmission. Identification of pAmpC and ESBLs in Enterobacteriaceae isolated from wildlife and aquaculture species may be evidence of environmental selection pressure arising from both human and veterinary use of β- lactams. Such selection pressure in animals could be reduced by the availability of reliable alternative control measures such as vaccines, bacteriophage treatments and/or competitive exclusion models for endemic production animal diseases such as colibacillosis. The global emergence and pandemic spread of extraintestinal pathogenic E. coli O25-ST131 strains expressing CTX-M-15 ESBL in humans and its recent detection in livestock, companion animals and wildlife is a major cause for concern and goes against the paradigm that Gramnegative pathogens do not necessarily have to lose virulence in compensation for acquiring resistance.
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia. darren.trott@adelaide.edu.au
Darren
D
Trott
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002511:Cephalosporins / Q000008:administration & dosage / Q000494:pharmacology; D004285:Dogs; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology / Q000635:transmission; D006801:Humans; D058751:Livestock / Q000382:microbiology; D057805:Pets / Q000382:microbiology; D015047:Zoonoses / Q000382:microbiology / Q000635:transmission; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics; D047090:beta-Lactams / Q000008:administration & dosage / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D047090:beta-Lactams; D001618:beta-Lactamases