title: Methicillin Resistant Staphylococcus aureus Carriage, Antibiotic Resistance and Molecular Pathogenicity among Healthy Individuals Exposed and Not Exposed to Hospital Environment.
abstract: BACKGROUND
  Healthcare workers as well as healthy community-dwelling individuals may be colonised by methicillin-resistant Staphylococcus aureus (MRSA). Healthcare workers who carry MRSA may transmit it to patients, causing various nosocomial infections. Literature shows that the differences between MRSA isolated from healthcare settings and from community settings, with regard to multi-drug resistance (traditionally exhibited by the former) and possession of pvl genes (traditionally exhibited by the latter), is diminishing due to a large community reservoir and increasing influx of community harboured strains into the hospital. However, there is no literature on the current scenario in India.
  
  
  OBJECTIVE
  This study examines the influence of exposure to hospital environment on MRSA carriage, antimicrobial resistance patterns of MRSA, and the presence of genes encoding five extracellular pathogenicity determinants (pvl, sea, seb, tsst-1 and hly a).
  
  
  METHODS
  Nasal, throat and palmar swabs were collected from 119 nursing students of the age group 18-23 years (exposed group) and 100 age matched pharmacy students (non-exposed group). S. aureus was identified and antibiogram obtained as per Clinical and Laboratory Standards Institute (CLSI) guidelines. MRSA was detected by cefoxitin disc diffusion test and by growth on oxacillin screen agar as per CLSI guidelines. Conventional PCR was performed for mecA, pvl, sea, seb, tsst-1 and hly a.
  
  
  RESULTS
  The differences in carrier rates, antibiotic resistance patterns and expression of extracellular pathogenicity determinants between MRSA isolates from the two study groups were not significant, and pvl was found in all the MRSA isolates.
  
  
  CONCLUSIONS
  The nursing students carried MRSA strains similar to those carried by the non-exposed group. Our results suggest that healthcare workers could act as a link and transmit MRSA acquired from the community to patients.
authors.affiliation: Assistant Professor, Department of Medical Microbiology, Sri Siddhartha Medical College , Tumkur, India .
authors.forename: Veena
authors.initials: V
authors.lastname: Krishnamurthy
authors.affiliation: Student, Sri Siddhartha Medical College , Tumkur, India .
authors.forename: Avinandan
authors.initials: A
authors.lastname: Saha
authors.affiliation: Associate Professor, Department of Medical Microbiology, Sri Siddhartha Medical College , Tumkur, India .
authors.forename: Bhadravati Virupaksha
authors.initials: BV
authors.lastname: Renushri
authors.affiliation: Head of Department, Department of Medical Microbiology, Sri Siddhartha Medical College , Tumkur, India .
authors.forename: Elkal Rajappa
authors.initials: ER
authors.lastname: Nagaraj
keywords: Antibiotic resistance; Hospital infection; Infectious disease transmission; MRSA; Panton-valentine leukocidin; Southern India