Globally, Staphylococcus aureus is the major causative organism for medical device associated infections. Of this, the proportion of Methicillin resistant Staphylococcus aureus (MRSA) has worldwide for the last two decades. Treatment of choice for MRSA is vancomycin, however, resistance to vancomycin by Staphylococcus species is being encountered from the midst of 1990’s. This study was conducted on 90 Pus samples from the wound of the infected orthopaedic implant, out of that, 75 isolates are pathogens and among that, 59 isolates are identified as Staphylococcus species, of which 31 isolates are Staphylococcus aureus and 28 isolates are Staphylococcus epidermidis. Among 31 Staphylococcus aureus, 19 are MSSA and 12 are MRSA, similarly in 28 Staphylococcus epidermidis 16 are MSSE and 12 are MRSE. Totally 24 isolates were Methicillin resistant Staphylococcus species, of which 14 isolates are showing multidrug resistance. Therefore, these 14 isolates (11 isolates of MRSA and 3 isolates of MRSE) are subjected to vancomycin MIC by using Agar dilution (0.5 & 2 McFarland standards) and Micro-broth dilution (0.5 McFarland standards) methods. Out of 14 tested, only 5 isolates are detected as VISA, and are screened for hVISA also, by using GRD E-test and no hVISA /hGISA are found. Hence, from the 14 isolates, 6 are VSSA, 5 are VISA and 3 are VSSE.

Keywords: MSSA-Methicillin sensitive Staphylococcus aureus, MRSA- Methicillin resistant Staphylococcus aureus, MSSE- Methicillin sensitive Staphylococcus epidermidis, MRSE- Methicillin resistant Staphylococcus epidermidis, VSSA-Vancomycin susceptible Staphylococcus aureus, VISA- Vancomycin intermediate Staphylococcus aureus, hVISA- Heteroresistant Vancomycin intermediate Staphylococcus aureus, VRSA- Vancomycin resistant Staphylococcus aureus, GRD E-Test-Glycopeptide resistant detection Epsilometer Test, CLSI-Clinical and Laboratory standards  Institute, MIC-Minimum inhibitory concentration.

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Dr Sujatha.K

Stanley Medical College