title: Evaluation of antimicrobial resistance and virulence of enterococci from equipment surfaces, raw materials, and traditional cheeses.
abstract: Forty enterococci isolated along the production chains of three traditional cheeses (PDO Pecorino Siciliano, PDO Vastedda della Valle del Belìce, and Caciocavallo Palermitano) made in Sicily (southern Italy) were studied for the assessment of their antibiotic resistance and virulence by a combined phenotypic/genotypic approach. A total of 31 Enterococcus displayed resistance to at least one or more of the antimicrobials tested. The strains exhibited high percentages of resistance to erythromycin (52.5%), ciprofloxacin (35.0%), quinupristin-dalfopristin (20.0%), tetracycline (17.5%), and high-level streptomycin (5.0%). The presence of tet(M), cat(pC221), and aadE genes for resistance to tetracycline, chloramphenicol, and streptomycin, respectively, was registered in all strains with resistance phenotype. The erm(B) gene was not detected in any erythromycin-resistant strain. The Enterococcus strains were further tested by PCR for the presence of virulence genes, namely, gelE, asa1, efaA, ace, and esp. Twenty strains were positive for all virulence genes tested. Among the enterococci isolated from final cheeses, three strains (representing 33.3% of total cheese strains) were sensible to all antimicrobials tested and did not carry any virulence factor. Although this study confirmed that the majority of dairy enterococci are vectors for the dissemination of antimicrobial resistance and virulence genes, only two strains showed a high resistance to aminoglycosides, commonly administered to combat enterococci responsible for human infections. Furthermore, the presence of the strains E. casseliflavus FMAC163, E. durans FMAC134B, and E. faecium PON94 without risk determinants, found at dominating levels over the Enterococcus populations in the processed products, stimulates further investigations for their future applications in cheese making. All strains devoid of the undesired traits were isolated from stretched cheeses. Thus, this cheese typology represents an interesting environment to deepen the studies on the risk/benefit role of enterococci in fermented foods for their qualified presumption of safety (QPS) assessment.
authors.affiliation: Dipartimento Scienze Agrarie e Forestali, Università di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy; Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
authors.forename: Raimondo
authors.initials: R
authors.lastname: Gaglio
authors.affiliation: Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
authors.forename: Natacha
authors.initials: N
authors.lastname: Couto
authors.affiliation: Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
authors.forename: Cátia
authors.initials: C
authors.lastname: Marques
authors.affiliation: ITQB-Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: de Fatima Silva Lopes
authors.affiliation: Dipartimento Scienze Agrarie e Forestali, Università di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Moschetti
authors.affiliation: Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
authors.forename: Constança
authors.initials: C
authors.lastname: Pomba
authors.affiliation: Dipartimento Scienze Agrarie e Forestali, Università di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy. Electronic address: luca.settanni@unipa.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Settanni
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D002611:Cheese / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D016983:Enterococcus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004866:Equipment Contamination; D004864:Equipment and Supplies / Q000382:microbiology*; D004917:Erythromycin / Q000494:pharmacology; D005511:Food Handling / Q000295:instrumentation; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D007558:Italy; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D004917:Erythromycin
keywords: Animal rennet; Antimicrobial resistance; Enterococcus; Raw milk; Traditional cheese; Virulence; Wooden vat