DETECTION OF BIOFILM IN COAGULASE NEGATIVE STAPHYLOCOCCUS: COMPARISION OF PHENOTYPIC METHODS
Dr. Smruti Mohanty and Dr. Laxmi Kant Mohanty*
Coagulase negative Staphylococci (CoNS) are a major component of the normal flora of the cutaneous ecosystem and act as commensal or saprophytic organisms. The ability to form biofilm plays an important role in contributing virulence of Coagulase Negative Staphylococcus (CoNS). It is considered as normal commensal and shown to cause infections in neonates and immunocompromised patients, especially with indwelling medical devices. The ability to form biofilm plays an important role in contributing virulence of CoNS. Also CoNS is found to be associated with nosocomial infections. The present study has been planned to detect biofilm production and also to evaluate three phenotypic methods. Aim: To detect biofilm production in CoNS from the clinical samples phenotypically by using: Tissue culture plate method (TCP), Tube adherence method, Congo red agar method (CRA). Materials and Methods: 100 CoNS isolates were subjected to species identification by standard biochemical tests. Biofilm detection of all isolates was done by TCP, CRA and tube method. Results: Of the total 1058 culture positives isolates 100(9.45%) were identified as CoNS. Of the total 100 isolates 54% were identified as S. epidermidis, 14 (14%) were identified as S. haemolyticus, 10 (10%) were identified as S. capitis, 8 (8%) as S. cohinii, and 14 (14%) as S. Saprophyticus. Of the total isolates biofilm production was seen in 62(62%) isolates by Tissue culture plate (TCP). By Congo red agar method biofilm production was 63 (63%). In tube method biofilm production was in 66 (66%) isolates Conclusions: Amongst phenotypic methods CRA was more sensitive and can be easily performed in the routine laboratories laboratory and can be used as a screening test for detection of biofilm.
Keywords: Coagulase negative Staphylococci (CoNS) detection of biofilm.
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