title: Heavy metal and disinfectant resistance genes among livestock-associated methicillin-resistant Staphylococcus aureus isolates.
abstract: Livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has emerged in animal production worldwide. Most LA-MRSA in Europe belong to the clonal complex (CC) 398. The reason for the LA-MRSA emergence is not fully understood. Besides antimicrobial agents used for therapy, other substances with antimicrobial activity applied in animal feed, including metal-containing compounds might contribute to their selection. Some of these genes have been found in various novel SCCmec cassettes. The aim of this study was to assess the occurrence of metal-resistance genes among a LA-S. aureus collection [n=554, including 542 MRSA and 12 methicillin-susceptible S. aureus (MSSA)] isolated from livestock and food thereof. Most LA-MRSA isolates (76%) carried at least one metal-resistance gene. Among the LA-MRSA CC398 isolates (n=456), 4.8%, 0.2%, 24.3% and 71.5% were positive for arsA (arsenic compounds), cadD (cadmium), copB (copper) and czrC (zinc/cadmium) resistance genes, respectively. In contrast, among the LA-MRSA non-CC398 isolates (n=86), 1.2%, 18.6% and 16.3% were positive for the cadD, copB and czrC genes, respectively, and none were positive for arsA. Of the LA-MRSA CC398 isolates, 72% carried one metal-resistance gene, and the remaining harboured two or more in different combinations. Differences between LA-MRSA CC398 and non-CC398 were statistically significant for arsA and czrC. The czrC gene was almost exclusively found (98%) in the presence of SCCmec V in both CC398 and non-CC398 LA-MRSA isolates from different sources. Regarding the LA-MSSA isolates (n=12), some (n=4) were also positive for metal-resistance genes. This study shows that genes potentially conferring metal-resistance are frequently present in LA-MRSA.
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany; Department of Bacterial Diseases, Veterinary and Agrochemical Research Centre (CODA-CERVA), Brussels, Groeselenbergstraat 99, B-1180 Ukkel, Belgium.
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Argudín
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Lauzat
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Kraushaar
authors.affiliation: Istituto Zooprofilattico Sperimentale del Lazio e della Toscana "M. Aleandri" (IZSLT), Via Appia Nuova 1411, 00178, Rome, Italy.
authors.forename: Patricia
authors.initials: P
authors.lastname: Alba
authors.affiliation: Technical University of Denmark (DTU), National Food Institute, Research group for Genomic Epidemiology, Søltofts Plads Building 221, 2800 Lyngby, Denmark.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Agerso
authors.affiliation: Technical University of Denmark (DTU), National Food Institute, Research group for Genomic Epidemiology, Søltofts Plads Building 221, 2800 Lyngby, Denmark.
authors.forename: Lina
authors.initials: L
authors.lastname: Cavaco
authors.affiliation: Department of Biomedical Sciences, Ross University, P.O. Box 334, Basseterre, St Kitts, West Indies; Department of Pathology, Bacteriology, and Avian Diseases, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Butaye
authors.affiliation: Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense Madrid (UCM), Madrid, Spain.
authors.forename: M Concepción
authors.initials: MC
authors.lastname: Porrero
authors.affiliation: Istituto Zooprofilattico Sperimentale del Lazio e della Toscana "M. Aleandri" (IZSLT), Via Appia Nuova 1411, 00178, Rome, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Battisti
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany.
authors.forename: Bernd-Alois
authors.initials: BA
authors.lastname: Tenhagen
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Fetsch
authors.affiliation: Department of Biological Safety, Federal Institute for Risk Assessment (BfR), Max-Dohrn-Straße 8-10, Berlin, Germany. Electronic address: beatriz.guerra@efsa.europa.eu.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Guerra
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004202:Disinfectants / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005060:Europe; D058751:Livestock / Q000382:microbiology*; D019216:Metals, Heavy / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics*; D013211:Staphylococcus aureus / Q000235:genetics
chemical_list: D004202:Disinfectants; D019216:Metals, Heavy
keywords: Arsenic compounds; Cadmium; Copper; SCCmec; Zinc