Antimicrobial resistance of pet-derived bacteria in China, 2000-2020.

With the rapid growth of the pet industry in China, bacterial infectious diseases in pets have increased, highlighting the need to monitor antimicrobial resistance (AMR) in pet-derived bacteria to improve the diagnosis and treatment. Before the establishment of the China Antimicrobial Resistance Surveillance Network for Pets (CARPet) in 2021, a comprehensive analysis of such data in China was lacking. Our review of 38 point-prevalence surveys conducted between 2000 and 2020 revealed increasing trends in AMR among pet-derived , , spp., spp., and other bacterial pathogens in China. Notable resistance to β-lactams and fluoroquinolones, which are largely used in both pets and livestock animals, was observed. For example, resistance rates for ampicillin and ciprofloxacin in frequently exceeded 50.0%, with up to 41.3% of the isolates producing extended-spectrum β-lactamases. The emergence of carbapenem-resistant and , carrying and genes, highlighted the need for vigilant monitoring. The detection rate of SCC (Staphylococcal Cassette Chromosome ), a genetic element associated with methicillin resistance, in isolated from pets in China was found to be over 40.0%. The resistance rate of to vancomycin was 2.1% (5/223) in East China, which was higher than the detection rate of human-derived vancomycin-resistant (0.1%, 12/11,215). Establishing the national AMR surveillance network CARPet was crucial, focusing on representative cities, diverse clinical samples, and including both commonly used antimicrobial agents in veterinary practice and critically important antimicrobial agents for human medicine, such as carbapenems, tigecycline, and vancomycin.