Study of vancomycin susceptibility pattern among Staphylococcus aureus isolated from superficial incisional surgical site infections

Abstract

Background: Staphylococcus aureus (S. aureus), a well-known superbug, is the leading cause of surgical site infections (SSIs). High proportions of methicillin resistant S. aureus (MRSA) increased the use of vancomycin and this led to emergence of strains with reduced susceptibility to vancomycin. The present study aimed to study the pattern of vancomycin susceptibility among S. aureus isolates from cases of superficial incisional SSIs. Methods: Wound swabs, from 205 patients with superficial SSIs, were collected. S. aureus isolates were identified to the species level using conventional microbiological methods. Antimicrobial susceptibility testing was performed using modified Kirby-Bauer disc diffusion technique. Staphylococcus aureus susceptibility to vancomycin was assessed using E-test. Results: Out of 205 SSI cases, 73 (35.6%) were found to be caused by S. aureus representing the major causative organism followed by Klebsiella (23.9%), and E. coli (14.6%). Antimicrobial profile of S. aureus isolates revealed maximum sensitivity to tigecycline and linezolid.  Methicillin resistant S. aureus (MRSA) represented 68.5% of isolates. E-test showed that all S. aureus isolates were sensitive to vancomycin. Conclusions:  Staphylococcus aureus was the most common cause of SSIs and vancomycin still an effective treatment for MRSA. However, a higher degree of resistance to the commonly used antibiotics was observed, amplifying the need of strict adherence to rational antibiotic policy.