Byline: A. Chaudhury, M. Nagaraja, A. Kumar
Staphylococcus epidermidis and Staphylococcus aureus are major causes of colonization and bio film formation in intravenous catheters. This frequently leads to catheter associated blood stream infection. Polysaccharide inter cellular adhesin (PIA) plays an important role in pathogenesis as it mediates the contact of bacterial cells with each other, resulting in the accumulation of a multilayered bio film. PIA production is under the control of the ica operon and this operon has been well documented not only in S. epidermidis[sup]  but also in S.aurues.[sup]  It has been documented that the regulation of ica operon expression and the resultant bio film formation may be altered by various environmental factors like anaerobicity, CO[sub] 2 levels, glucose and osmotic changes. In recent years, the influence of methicillin susceptibility on bio film formation and ica expression among S. aureus isolates have been studied, revealing some important findings;[sup]  though similar studies have not been done for S. epidermidis . Our study has examined the methicillin sensitivity / resistance on bio film formation among S. aureus and S. epidermidis isolates from venous catheter tips.
Isolates of Staphylococci from venous catheters have been used. A total of 60 representative strains consisting 15 each of methicillin sensitive S. aureus (MSSA), methicillin resistant S. aureus (MRSA), methicillin sensitive S. epidermidis (MSSE) and methicillin resistant S. epidermidis (MRSE) were included. Methicillin sensitivity testing was done using oxacillin, 1 [micro]g disks (Hi-media, India) and reconfirmed with cefoxitin, 30 ig disks (Hi Media, India). The antibogram of the S. aureus and the S. epidermidis...