title: Can Panton Valentine Leukocidin Gene And Clindamycin Susceptibility Serve As Predictors of Community Origin of MRSA From Skin and Soft Tissue Infections?
abstract: BACKGROUND
  Community associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) strains have begun to replace Hospital Associated MRSA (HA-MRSA) strains in hospital settings all over the world. With the epidemiological distinctions between these strains beginning to become ill-defined, the categorisation of a strain as CA-MRSA or HA-MRSA is dependent on molecular methods to detect the presence of SCCmec (Staphylococcal Cassette Chromosome mec) elements. However other markers like the presence of Panton Valentine Leukocidin toxin (pvl) genes or Clindamycin susceptibility may also be associated with community origin of MRSA.
  
  
  OBJECTIVE
  To determine the prevalence of CA-MRSA among MRSA strains isolated from skin and soft tissue infections and to evaluate the usefulness of Panton Valentine Leukocidin and Clindamycin susceptibility as markers of community origin of MRSA.
  
  
  METHODS
  One hundred isolates of MRSA from skin and soft tissue were studied for the presence of SCCmec IV and V genes and Panton valentine leukocidin gene by Polymerase chain reaction. Inducible clindamycin resistance was screened for using the D-test.
  
  
  METHODS
  Fischer's exact test. A p-value <0.05 was considered significant.
  
  
  RESULTS
  Eighteen out of 100 MRSA strains were found to be CA-MRSA based on presence of SCCmecV. The proportion of Panton Valentine Leukocidin gene carriage among CA- MRSA as compared to HA-MRSA was found to be statistically significant (p<0.0001). Among the CA-MRSA strains, 94.4% were found to be susceptible to Clindamycin as against only 13.4% of the HA-MRSA strains (p<0.0001). The odds of an MRSA strain being CA-MRSA if it was both Clindamycin susceptible and PVL gene positive was calculated to be 68.25 (p<0.0001).
  
  
  CONCLUSIONS
  Both Clindamycin susceptibility and pvl gene carriage were found to be independent predictors of community origin of MRSA, but taken together the association was highly significant.
authors.affiliation: Senior Resident, Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, (JIPMER) , India .
authors.forename: Nandita
authors.initials: N
authors.lastname: Shashindran
authors.affiliation: PhD scholar, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) Department of Microbiology, India .
authors.forename: Niveditha
authors.initials: N
authors.lastname: Nagasundaram
authors.affiliation: Professor and Head, Department of Dermatology and Sexually Transmitted Diseases, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) , India .
authors.forename: Devinder Mohan
authors.initials: DM
authors.lastname: Thappa
authors.affiliation: Professor, Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) , India .
authors.forename: Sujatha
authors.initials: S
authors.lastname: Sistla
keywords: CA-MRSA; PVL; SSTIs