The Emergence of Antimicrobial Resistance and Virulence Characteristics in <i>Enterococcus</i> Species Isolated from Bovine Milk
Beatriz Rizzo Paschoalini,
Karen Vanessa Munive Nuñez,
Juliana Takahashi Maffei,
Hélio Langoni,
Felipe Freitas Guimarães,
Clarice Gebara,
Natylane Eufransino Freitas,
Marcos Veiga dos Santos,
Carlos Eduardo Fidelis,
Roberto Kappes,
Mônica Correia Gonçalves,
Nathália Cristina Cirone Silva
Affiliations
Beatriz Rizzo Paschoalini
Department of Food Science and Nutrition, School of Food Engineering, University of Campinas, Campinas 13083-862, SP, Brazil
Karen Vanessa Munive Nuñez
Department of Food Science and Nutrition, School of Food Engineering, University of Campinas, Campinas 13083-862, SP, Brazil
Juliana Takahashi Maffei
Department of Food Science and Nutrition, School of Food Engineering, University of Campinas, Campinas 13083-862, SP, Brazil
Hélio Langoni
Department of Animal Production and Preventive Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, São Paulo State University, Botucatu 18618-681, SP, Brazil
Felipe Freitas Guimarães
Department of Animal Production and Preventive Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, São Paulo State University, Botucatu 18618-681, SP, Brazil
Clarice Gebara
Food Research Center, School of Veterinary Medicine and Animal Science, Federal University of Goiás, Campus Road, Goiânia 74690-900, GO, Brazil
Natylane Eufransino Freitas
Food Research Center, School of Veterinary Medicine and Animal Science, Federal University of Goiás, Campus Road, Goiânia 74690-900, GO, Brazil
Marcos Veiga dos Santos
Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, SP, Brazil
Carlos Eduardo Fidelis
Department of Animal Nutrition and Production, School of Veterinary Medicine and Animal Sciences, University of São Paulo (USP), Pirassununga 13635-900, SP, Brazil
Roberto Kappes
Center for Agroveterinary Sciences, University of the State of Santa Catarina, Lages 88520-000, SC, Brazil
Mônica Correia Gonçalves
Center for Agro-Food Science and Technology, Federal University of Campina Grande, Campina Grande 58840-000, PB, Brazil
Nathália Cristina Cirone Silva
Department of Food Science and Nutrition, School of Food Engineering, University of Campinas, Campinas 13083-862, SP, Brazil
Enterococcus spp., including E. faecalis and E. faecium, pose risks to dairy farms as opportunistic pathogens. The study evaluates antimicrobial resistance (AMR) and virulence characteristics of Enterococcus spp. isolated from bovine milk. Bile esculin agar was used to assess 1471 milk samples, followed by colony identification, gram staining, catalase tests, and 45 °C incubation. PCR analysis targeted E. faecalis and E. faecium in characteristic Enterococcus spp. colonies, with MALDI-TOF used for negative samples. Multiple tests, including disk diffusion, chromogenic VRE agar for vancomycin resistance, Vancomycin Etest® for MIC determination, and PCR for virulence factors (cylA, esp, efaA, ace, asa1, gelE, and hyl genes), were performed. Out of 100 identified strains, E. durans (30.66%), E. faecium (26.28%), and E. faecalis (18.25%) were predominant. AMR in Enterococcus spp. varied, with the highest rates against rifampicin (27%), tetracycline (20%), and erythromycin (18%). Linezolid (5%), vancomycin, ciprofloxacin, and teicoplanin (3% each) had lower prevalence. E. faecium and E. faecalis showed high AMR to rifampicin, erythromycin, and tetracycline. Thirty-two strains (18.98%) grew on VRE Chromoselect agar, while 4 (2 E. faecalis and 2 E. faecium) showed vancomycin resistance by MIC values. E. faecalis carried gelE (45.5%) and asa1 (36%), and E. gallinarum had 9.1% with the asa1 gene. Detecting resistant Enterococcus in bovine milk supports control strategies for enterococci on dairy farms, highlighting AMR concerns in the food chain.
