Antibiotic Resistance of Enterococcus Species in Ornamental Animal Feed

SIMPLE SUMMARY: Numerous studies have already reported the presence of different antibiotic-resistant Enterococcus species in food-producing animals, animal products and pet food. However, studies specifically evaluating antimicrobial resistance in Enterococcus spp. in ornamental animals and their food are scarce. Therefore, this study aimed to identify Enterococcus spp. and their antibiotic-resistant patterns in ornamental animal feed, as this could lead to the spread of antimicrobial resistance to humans due to their close contact with these animals. ABSTRACT: Enterococcus is a bacterial genus that is strongly associated with nosocomial infections and has a high capacity to transfer and acquire resistance genes. In this study, the main objective was to evaluate the presence of Enterococcus species in ornamental animal feed and characterize their antimicrobial resistance and virulence factors. Antimicrobial susceptibility was determined using 14 antimicrobial agents by the disk diffusion method, complemented by genotypic analysis to identify Enterococcus species and the presence of 14 antimicrobial resistance and 10 virulence genes. From 57 samples of ornamental animal feed, 103 Enterococcus isolates were recovered from 15 bird, 9 fish and 4 reptile feed samples. Enterococcus isolates were highly resistance to rifampicin (78%) and erythromycin (48%), and 48% of isolates were classified as multidrug-resistant. Enterococcus faecalis (36.7%) and E. faecium (31.7%) were the species most frequently identified. Most isolates carried the resistance genes ermB (57%) and tetL (52%) and the virulence genes, cylL (52%) and esp (40%). Enterococcus gallinarum was the species with the highest number of multidrug-resistant isolates (50%) and virulence genes (80%). These results highlight the high levels of antibiotic-resistant Enterococcus spp. present in ornamental animal feed and the growing interaction of these animals with humans as a public health concern.