Comparison Study of Accuracy of phenotypic Methods for Detecting Biofilm Producer Staphylococcus aureus Isolates

Microorganisms growing in a biofilm are correlating with chronic human infections and are highly resistant to immune system, antimicrobial agents and difficult to remove from the infected host. There are different methods to determine biofilm production such as Microtitre Plate (MtP) method , Congo Red Agar method (CRA) and Tube Method (TA) method .This study was carried out from December 2015 to september 2016, 580 specimens were obtained from patients at different hospitals in Erbil city/ Iraq. Staphylococcus aureus clinical isolates were identified phenotypically by different biochemical and molecular tests. One hundred isolates were found to be Staphylococcus aureus. MtP, CRA and TA tested Biofilm determination. This study was aimed to compare three methods of biofilm production. The results found that the accuracy and specificity of MtP was 100%, while it was 87%, 75% and 91% ,81.25% for CRA and TA methods respectively . The MtP method was considered to be superior to CRA and TA methods, and this method was the better screening for biofilm formation than CRA and TA methods, so this method can be a reliable quantitative tool for detection of biofilm formation in clinical isolates of S. aureus.