title: Molecular Markers of Antimicrobial Resistance in Methicillin-Resistant Staphylococcus aureus SCCmec IV Presenting Different Genetic Backgrounds.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec type IV has emerged in hospitals worldwide. The aim of this study was to evaluate phenotypic and molecular characteristics of antimicrobial resistance in MRSA SCCmec IV isolates, presenting different genetic backgrounds, isolated from hospitals in Rio de Janeiro. The antimicrobial resistance of 128 S. aureus type IV isolates from 11 hospitals was characterized by the disk diffusion test and minimum inhibitory concentration (MIC) test. Mutations in parC gene, which encodes ciprofloxacin resistance, and genes associated with macrolide-lincosamide-streptogramin B (MLSb) resistance were also investigated. MRSA isolates belonging to USA400/ST1 (60 isolates), USA800/ST5 (40), USA1100/ST30 (13), and other 11 (15) lineages were mainly resistant to erythromycin (68%), ciprofloxacin (56%), and clindamycin (50%). The highest antimicrobial resistance rates were found among USA400 isolates (p < 0.05). The majority of them (90%) carried only the erm(C) gene and mainly presented two mutation types in the parC gene. The msr(A) gene was most frequently found among USA800 isolates (p < 0.05). Among MRSA type IV isolates from Rio de Janeiro hospitals, multiresistance, including mutations in parC gene, was associated to the USA400/ST1, while the msr(A) gene was associated with USA800/ST5 isolates, highlighting that these lineages could have more potential to persist in a hospital environment.
authors.affiliation: 1 Department of Medical Microbiology, Institute of Microbiology , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .
authors.forename: Pricilla Dias Moura
authors.initials: PD
authors.lastname: de Matos
authors.affiliation: 1 Department of Medical Microbiology, Institute of Microbiology , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .
authors.forename: Tamara Lopes Rocha
authors.initials: TL
authors.lastname: de Oliveira
authors.affiliation: 1 Department of Medical Microbiology, Institute of Microbiology , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .
authors.forename: Fernanda Sampaio
authors.initials: FS
authors.lastname: Cavalcante
authors.affiliation: 2 School of Dentistry, Universidade Estácio de Sá , Rio de Janeiro, Brazil .
authors.forename: Dennis Carvalho
authors.initials: DC
authors.lastname: Ferreira
authors.affiliation: 3 Department of Basic Sciences, Universidade Federal Fluminense , Rio de Janeiro, Brazil .
authors.forename: Natália Lopes Pontes
authors.initials: NL
authors.lastname: Iorio
authors.affiliation: 4 Federal Institute of Education, Science and Technology of Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Eliezer Menezes
authors.initials: EM
authors.lastname: Pereira
authors.affiliation: 1 Department of Medical Microbiology, Institute of Microbiology , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .
authors.forename: Raiane Cardoso
authors.initials: RC
authors.lastname: Chamon
authors.affiliation: 1 Department of Medical Microbiology, Institute of Microbiology , Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil .
authors.forename: Kátia Regina Netto
authors.initials: KR
authors.lastname: Dos Santos
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D001938:Brazil / Q000453:epidemiology; D027101:DNA Topoisomerase IV / Q000235:genetics* / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006761:Hospitals; D006801:Humans; D055231:Lincosamides / Q000494:pharmacology; D018942:Macrolides / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D051150:Methionine Sulfoxide Reductases / Q000235:genetics* / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D009154:Mutation; D015363:Quinolones / Q000494:pharmacology; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D025381:Streptogramin B / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D055231:Lincosamides; D018942:Macrolides; D015363:Quinolones; D025381:Streptogramin B; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase; D027101:DNA Topoisomerase IV
keywords: MRSA; SCCmec IV; lineages; macrolides; quinolones; resistance genes