title: Multidrug-resistant enterococci in animal meat and faeces and co-transfer of resistance from an Enterococcus durans to a human Enterococcus faecium.
abstract: Forty-eight isolates resistant to at least two antibiotics were selected from 53 antibiotic-resistant enterococci from chicken and pig meat and faeces and analysed for specific resistance determinants. Of the 48 multidrug-resistant (MDR) strains, 31 were resistant to two antibiotics (29 to erythromycin and tetracycline, 1 to erythromycin and vancomycin, 1 to vancomycin and tetracycline), 14 to three (erythromycin, tetracycline and vancomycin or ampicillin) and 3 to four (erythromycin, vancomycin, ampicillin and gentamicin). erm(B), tet(M), vanA and aac (6')-Ie aph (2'')-Ia were the antibiotic resistance genes most frequently detected. All 48 MDR enterococci were susceptible to linezolid and daptomycin. Enterococcus faecalis (16), Enterococcus faecium (8), Enterococcus mundtii (2) and Enterococcus gallinarum (1) were identified in meat, and E. faecium (13) and Enterococcus durans (13) in faeces. Clonal spread was not detected, suggesting a large role of gene transfer in the dissemination of antibiotic resistance. Conjugative transfer of resistance genes was more successful when donors were enterococcal strains isolated from faeces; co-transfer of vanA and erm(B) to a human E. faecium occurred from both E. faecium and E. durans pig faecal strains. These data show that multidrug resistance can be found in food and animal species other than E. faecium and E. faecalis, and that these species can efficiently transfer antibiotic resistance to human strains in inter-specific matings. In particular, the occurrence of MDR E. durans in the animal reservoir could have a role in the emergence of human enterococcal infections difficult to eradicate with antibiotics.
authors.affiliation: Department of Biomedical Sciences-Section of Microbiology, Polytechnic University of Marche, Tronto 10/A, 60020 Torrette di Ancona, Italy. c.vignaroli@univpm.it
authors.forename: Carla
authors.initials: C
authors.lastname: Vignaroli
authors.forename: Giada
authors.initials: G
authors.lastname: Zandri
authors.forename: Lucia
authors.initials: L
authors.lastname: Aquilanti
authors.forename: Sonia
authors.initials: S
authors.lastname: Pasquaroli
authors.forename: Francesca
authors.initials: F
authors.lastname: Biavasco
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002645:Chickens / Q000382:microbiology*; D003227:Conjugation, Genetic; D004197:Disease Reservoirs / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D016983:Enterococcus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D016984:Enterococcus faecium / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D013552:Swine / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins