Role of insertion sequence element is256 as a virulence marker and its association with biofilm formation among methicillin-resistant Staphylococcus epidermidis from hospital and community settings in Chennai, South India.

The objective of this study was to detect the association of biofilm formation with IS256 among clinical and carrier isolates of methicillin-resistant Staphylococcus epidermidis (MRSE). A total of 71 MRSE isolates were included in this study. Phenotypic detection of biofilm formation was done by Congo red agar method. Detection of genes associated with biofilm formation (icaAD, aap and atlE) and insertion sequence IS256 was done by polymerase chain reaction. Of the 71 MRSE isolates,19/40 (47.5%) clinical isolates from hospital settings and 11/31 (35.5%) carrier isolates from community settings respectively were found to be positive for all the three genes tested, namely, icaAD+, aap+ and atlE+ genes. Nearly 80% of clinical isolates were found to harbour IS256, whereas only 13% of community isolates harboured IS256.