Detection of biofilm formation among the clinical isolates of Staphylococci: an evaluation of three different screening methods.
OBJECTIVE
The purpose of this study was to evaluate three methods for detection of biofilm formation in staphylococci.


METHODS
For detection of biofilm formation, 152 clinical isolates of Staphylococcus spp. were screened by tissue culture plate (TCP), Tube method (TM) and Congo red agar (CRA) method.


RESULTS
Of the 152 Staphylococcus spp. 88(57.8%) displayed a biofilm-positive phenotype under the optimized conditions in the TCP method and strains were further classified as high 22 (14.47 %) and moderate 60 (39.4 %) while in 70 (46.0 %) isolates weak or no biofilm was detected. Though TM correlated well with the TCP test for 18 (11.8 %) strongly biofilm producing strains, weak producers were difficult to discriminate from biofilm negative isolates. Screening on CRA does not correlate well with either of the two methods for detecting biofilm formation in staphylococci.


CONCLUSIONS
The TCP method was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation by staphylococci and has the advantage of being a quantitative model to study the adherence of staphylococci on biomedical devices.
Mathur
T
T
New Drug Discovery Research, Ranbaxy Research Laboratories, Gurgaon-122 001, Haryana, India. mathurtarun@ranbaxy.com
Singhal
S
S
Khan
S
S
Upadhyay
D J
DJ
Fatma
T
T
Rattan
A
A
D000362:Agar; D001422:Bacterial Adhesion; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods; D018441:Biofilms / Q000254:growth & development*; D003224:Congo Red; D003470:Culture Media; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013210:Staphylococcus / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification
D003470:Culture Media; D003224:Congo Red; D000362:Agar