360. Characterization of Methicillin Resistant Staphylococcus aureus SCCmec type IV and SCCmec type V in an Indian Hospital : Expansion of Epidemic Clones of Sequence Type (ST) 22, ST 772 and ST 36
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • IDSA 2013 Poster slides final [Read-Only] [Compatibility Mod.pdf (636.6 kB)
  • Background: The hospital epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) has changed due to encroachment of community-associated (CA) MRSA strains into health care settings. We determined the clinical characteristics, antimicrobial susceptibility patterns and genotypes of MRSA isolated from inpatients with healthcare associated (HA) and community-associated skin and soft tissue infections (SSTIs). We also investigated the HA exposure effects on HA-SCCmec IV/V-MRSA by comparison with SCCmec IV/V MRSA isolated from outpatients without HA exposure. 

    Methods: Three hundred MRSA strains consisting of 200 strains from inpatients and 100 strains from outpatients were tested for antimicrobial susceptibilty, SCCmec typing, Panton-Valentine leucocidin (PVL) toxin, seh and arcA genes. Representative isolates of SCCmec types were further characterized by pulsed-field gel electrophoresis (PFGE), spa typing and multi-locus sequence typing (MLST). Based on SCCmec typing, HA-MRSA isolates were further divided into HA-SCCmec I/II/III-MRSA and HA-SCCmec IV/V-MRSA and CA-MRSA isolates into CA-SCCmec I/II/III-MRSA and CA-SCCmec IV/V-MRSA. 

    Results: Seventy-five (37.5%) HA-MRSA isolates had a SCCmec IV/V genotype. Eighty-three of 100 CA-MRSA isolates had a SCCmec IV/V genotype. There were no differences in clinical characteristics between patients with HA-SCCmec I/II/III-MRSA and HA-SCCmec IV/V-MRSA SSTIs.  In a multivariate model, HA-SCCmec IV/V-MRSA was associated with malignancy (p=0.03) and bone fractures (p=0.02) as compared to CA-SCCmec IV/V-MRSA. HA-SCCmec IV/V-MRSA was associated with PVL genes carriage compared to HA-SCCmec I/II/III-MRSA (p<0.001). HA-SCCmec IV/V-MRSA exhibited antimicrobial susceptibility patterns in between those of CA-SCCmec IV/V and the HA-SCCmec I/II/III-MRSA strains.  ST22-MRSA-IV (EMRSA-15), ST772-MRSA-V, ST36-MRSA-IV) and ST239:EMRSA-1:III were the major clones identified. 

    Conclusion: Our study documents the emergence of SCCmec IV and SCCmec V MRSA clones in our hospital. The dissemination of epidemic CA-MRSA clones in both inpatients and outpatients represent a challenge to infection control.

    Benu Dhawan, MD1, Chandrabhan Rao, MSc1, Edet E Udo, PhD2, Ravisekhar Gadepalli, PhD3, Sreenivas Vishnubhatla, PhD4 and Arti Kapil, MD1, (1)Microbiology, ALL India Institute Of Medical Sciences (AIIMS), NEW DELHI, India, (2)Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait, Kuwait, (3)Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA, TN, (4)Department of Biostatistics, ALL India Institute Of Medical Sciences (AIIMS), NEW DELHI, India


    B. Dhawan, None

    C. Rao, None

    E. E. Udo, None

    R. Gadepalli, None

    S. Vishnubhatla, None

    A. Kapil, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.