Antimicrobial Resistance: Alarming Rates of Resistant E. coli Detected in Cats and Dogs in Germany

A large-scale German study on antimicrobial resistance focused on Escherichia coli resistance to third-generation cephalosporins (cefovecin in veterinary medicine) in dogs and cats.   The researchers analyzed antimicrobial susceptibility test data from 3,491 German veterinary clinics between 2019 and 2021, representing 33.1% of the country’s veterinary practices. The results are alarming: the rate of phenotypic resistance to third-generation cephalosporins (3G) was 11.6% among the 25,491 E. coli strains isolated from canine and feline clinical specimens. A similar rate was observed in dogs (11.6%) and cats (11.7%). Geographically, regional differences of approximately 3% were observed. Some regions, such as Bavaria, had resistance rates of approximately 15%. In addition, the study highlighted cross-resistance, with significantly higher resistance rates to other antibiotics. This was particularly true for the sulfamethoxazole-trimethoprim combination, with a 30% resistance rate among C3G-resistant E. coli, compared to 12% for all isolated strains! Furthermore, variations were detected depending on the type of sample: resistance rates were lower in samples from the animals’ reproductive and urinary tracts compared to other organs. This study is the first to use such a large dataset covering dog and cat populations throughout Germany. Given the close contact between these animals and their owners, the results should be taken into account in the context of the potential transmission of resistant bacteria. By way of comparison, the rates of resistance to ceftazidime reported in human medicine are lower than the veterinary data from this study (6.7%). Finally, while this large-scale study focuses primarily on Escherichia coli resistance to cefovecin, the only third-generation cephalosporin authorized for veterinary medicine in pets, the results can be extrapolated to other cephalosporins used in human medicine and serve as an indicator of the high prevalence of antimicrobial resistance in E. coli.