USF St. Petersburg campus Faculty Publications

Evaluation of different microtiter plate-based methods for the quantitative assessment of Staphylococcus aureus biofilms

SelectedWorks Author Profiles:

Hossam Ashour

Document Type

Article

Publication Date

2014

ISSN

1746-0913

Abstract

Aim: To quantitatively assess Staphylococcus aureus biofilms. Materials & methods: In addition to the qualitative Congo red agar (CRA) method, we used the bioluminescence (BLM), safranine (SAF), crystal violet (CRV) and resazurin (RES) high-throughput microtiter plate-based quantitative assays. Results: 60.47% (26/43) of S. aureus clinical isolates were weak biofilm producers. The CRA method detected positive-slime phenotypes (13.95%), but was unable to distinguish weak from negative producers. BLM assays demonstrated significant correlations with RES (highest), CRV and SAF (lowest). Lower coefficient of variation values indicate precision. BLM scored highest precision (coefficient of variation = 0.013) followed by RES, SAF and CRV. Conclusion: BLM and RES detect live biomass in S. aureus biofilms (for physiological studies). SAF and CRV detect live/dead bacteria plus biofilm matrix (for monitoring overall biofilm architecture, not only its cell viability). Reliable assays are essential for effective biofilm therapy.

Publisher

Future Medicine Ltd.

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