title: Antimicrobial Resistance and Molecular Characteristics of Nasal Staphylococcus aureus Isolates From Newly Admitted Inpatients.
abstract: Staphylococcus aureus, or methicillin-resistant S. aureus (MRSA), is a significant pathogen in both nosocomial and community infections. Community-associated MRSA (CA-MRSA) strains tend to be multi-drug resistant and to invade hospital settings. This study aimed to assess the antimicrobial resistance and molecular characteristicsof nasal S. aureus among newlyadmitted inpatients.In the present study, 66 S. aureus isolates, including 10 healthcare-associated MRSA (HA-MRSA), 8 CA-MRSA, and 48 methicillin-sensitive S. aureus (MSSA) strains, were found in the nasal cavities of 62 patients by screening 292 newlyadmitted patients. Antimicrobial resistance and molecular characteristics of these isolates, including spa-type, sequence type (ST) and SCCmec type, were investigated. All isolates were sensitive to linezolid, teicoplanin, and quinupristin/dalfopristin, but high levels of resistance to penicillin and erythromycin were detected. According to D-test and erm gene detection results, the cMLS(B) and iMLS(B) phenotypes were detected in 24 and 16 isolates, respectively. All 10 HA-MRSA strains displayed the cMLS(B) phenotypemediated by ermA or ermA/ermC, while the cMLS(B) CA-MRSA and MSSA strains carried the ermB gene. Molecular characterization revealedall 10 HA-MRSA strains were derived from the ST239-SCCmec III clone, and four out of eight CA-MRSA strains were t437-ST59-SCCmec V. The results suggest that patients play an indispensable role in transmitting epidemic CA-MRSA and HA-MRSA strains.
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
authors.forename: Kangde
authors.initials: K
authors.lastname: Sun
authors.affiliation: Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China. dongdanfeng0327@hotmail.com.
authors.forename: Danfeng
authors.initials: D
authors.lastname: Dong
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
authors.forename: Qingqiong
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
authors.forename: Yibing
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China. fuxiang_chen@hotmail.com.
authors.forename: Fuxiang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D006801:Humans; D007297:Inpatients; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008780:Methyltransferases / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009296:Nasal Cavity / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008780:Methyltransferases; C431709:ErmA protein, Bacteria; C035181:rRNA (adenosine-O-2'-)methyltransferase
keywords: Antimicrobial resistance; CA-MRSA; Molecular characteristics; Nasal carriage; Staphylococcus aureus