Role of Intracellular Adhesion icaAD and agr genes in Biofilm Formation in Clinical S. aureus Isolates and Assessment of Two Phenotypic Methods.

Objective: To determine the role of and genes in biofilm formation and evaluate the consistency of two phenotypic methods for biofilm measurement.

Methods: A total of 81 clinical strains were included and analyzed for biofilm formation by two methods. The microtitration plate method was optimized using computational fluid dynamics and compared with the Congo red assay. The genes for and were detected using PCR.

Results: Of 81 isolates, biofilm production was detected in 43% isolates using Congo red method while microtiter plate assay showed biofilm production in 92% isolates. Both methods showed correlation in 30% isolates. PCR detection showed gene in 42 (52%) isolates. Out of 81 isolates 65 strains (80%) contained while 16 (20%) strains were non-typeable.

Conclusions: In conclusion, biofilm production was observed for both positive and negative isolates. Furthermore, the presence of genes was not associated with all biofilm producing strains as some strains negative for genes displayed biofilm production.