title: Changing Trends in Resistance Pattern of Methicillin Resistant Staphylococcus aureus.
abstract: BACKGROUND
  Methicillin resistance in Staphylococcus aureus is associated with multidrug resistance, an aggressive course, increased mortality and morbidity in both community and health care facilities. Monitoring of newly emerging and prevalent Methicillin Resistant Staphylococcus aureus (MRSA) strains for their resistance patterns to conventional as well as novel drugs, are essential for infection control.
  
  
  OBJECTIVE
  To study the changing trends in resistance patterns of MRSA at our hospital.
  
  
  METHODS
  This cross sectional study was carried out in a 750 bed tertiary care hospital in south India.
  
  
  METHODS
  One hundred and two clinical isolates of MRSA which were obtained in 2004-2011 were identified by using oxacillin, cefoxitin disc diffusion test and oxacillin screening agar test. Antibiotic susceptibility test was done for commonly used non beta lactam anti-Staphylococcal drugs, as well as for anti-MRSA drugs like vancomycin, linezolid, mupirocin and rifampicin. Minimum inhibitory concentration (MIC) of vancomycin was determined by using Vancomycin HiComb strip (Himedia, Mumbai, India). Statistical Analysis which was done: Chi-square test and proportions were used to compare the two groups.
  
  
  RESULTS
  MRSA isolates showed high resistance to co-trimoxazole (82.3%), ciprofloxacin (76.4%), gentamicin (64.7%) and tetracycline (49%) as compared to other drugs. High prevalence of ciprofloxacin resistance was detected, particularly among outpatients. Multi resistant MRSA with a ≥ 3 non-beta lactam agent resistance was 79%. All MRSA isolates were sensitive to vancomycin, linezolid, mupirocin and rifampicin. MRSA had displayed increase in resistance to most antibiotics except tetracycline in recent years.
  
  
  CONCLUSIONS
  Taking into consideration the prevalence of multidrug resistance in MRSA, resistance patterns should be evaluated periodically and antibiotic therapy should be guided by susceptibility testing.
authors.affiliation: Assistant Professor, Microbiology, Mahatma Gandhi Medical College & Research Institute , Pondicherry, India .
authors.forename: Arunava
authors.initials: A
authors.lastname: Kali
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Stephen
authors.forename: Sivaraman
authors.initials: S
authors.lastname: Umadevi
authors.forename: Shailesh
authors.initials: S
authors.lastname: Kumar
authors.forename: Noyal Mariya
authors.initials: NM
authors.lastname: Joseph
authors.forename: Sreenivasan
authors.initials: S
authors.lastname: Srirangaraj
keywords: Methicillin resistant Staphylococcus aureus; Multidrug resistance; Vancomycin