title: Surgical Site Infection by Methicillin ResistantStaphylococcus aureus- on Decline?
abstract: BACKGROUND
  Surgical Site Infection (SSI) is the most common healthcare associated infection that could be averted by antibiotics prophylaxis against the probable offending organisms. AsStaphylococcus aureushas been playing a substantial role in the aetiology of SSIs, Methicillin ResistantStaphylococcus aureus(MRSA) happens to be a problem while dealing with the postoperative wound infection.
  
  
  OBJECTIVE
  To determine the prevalence of SSI caused by MRSA and the antibiotic sensitivity pattern of MRSA.
  
  
  METHODS
  A cross-sectional study was conducted at Nil Ratan Sircar Medical College, Kolkata, West Bengal from July 2009 to December 2012. A total of 19,359 surgical procedures were done of which 3003 culture positive SSIs have been documented. The clinical samples were collected from patients of both sexes and all ages suspected to be suffering from SSI from different specialities. Samples were processed according to CLSI, 2007 guidelines. The isolated strains ofStaphylococcus aureuswere screened for MRSA by detection of resistance to Cefoxitin disc (zone of inhibition was ≤21 mm) and slidex staph latex agglutination tests were done on cefoxitin resistant strains to spot phenotypic expression ofmec Agene. Then PCR was performed for detection ofmecAgene. Antibiotic sensitivity test was done following Kirby Bauer technique.
  
  
  RESULTS
  In this 3½ year study, 1049Staphylococcus aureus(34.93%) were reported from 3003 cases of SSI followed byEscherichia coli(20.34%),Klebsiellaspp. (18.08%),Pseudomonasspp. (7.99%),Acinetobacterspp. (7.49%) respectively. Among theStaphylococcus aureus,267 strains were derived as MRSA (25.45%). MRSA were isolated from 167 (62.54%) male patients and 100 (37.45%) female patients having surgical site infections. Inpatients and outpatients distribution of MRSA were 235 (88.01%) and 32 (11.98%) respectively. Majority of the MRSA cases were reported from Surgery (12.49%) and Orthopaedics (11.85%) departments in the age group above 75 years (15.63%). The MRSA strains have been found to be 100% sensitive to linezolid and tigecycline followed by fucidin (92.51%), mupirocin (88.39%), levofloxacin (75.66%) and doxycycline (72.28%). No vancomycin resistant strains were detected, but 3 strains (1.12%) were found to be intermediately susceptible to it (VISA). Incidence of MRSA in SSI has been decreased by 15.17 % in 2012 in comparison to 2009. PCR revealedmecAgene was present in 96.25% of cefoxitin resistantStaphylococcus aureusstrains.
  
  
  CONCLUSIONS
  Staphylococcus aureusbeing the predominant organism causing SSIs, MRSA needs the attention for its resistance to commonly used antibiotics in the hospital like penicillin, cephalosporin group of drugs. Regular monitoring of the MRSA, involved in the SSI of a particular setup is the basic requirement to trim down the incidence of the postoperative wound infections by proper antibiotic prophylaxis.
authors: Professor, Department of Microbiology, NRS Medical College , Kolkata, West Bengal, India .
authors: Susmita
authors: S
authors: Bhattacharya
authors: Associate Professor, Department of Microbiology, College of Medicine and JNM Hospital , Kalyani, Nadia, West Bengal, India .
authors: Kuhu
authors: K
authors: Pal
authors: PhD Student, Department of Microbiology, Medical College , Kolkata, West Bengal, India .
authors: Sonia
authors: S
authors: Jain
authors: Assistant Professor, Department of Microbiology, NRS Medical College , Kolkata, West Bengal, India .
authors: Shiv Sekhar
authors: SS
authors: Chatterjee
authors: Demonstrator, Department of Microbiology, NRS Medical College , Kolkata, West Bengal, India .
authors: Jayashree
authors: J
authors: Konar
keywords: Antibiotic resistance; Postoperative wound infection; Surveillance