Distribution of genes encoding biofilm production in Staphylococcus aureus in raw milk supplied in Tehran

Staphylococcus aureus is one of the most important virulence factors in milk and dairy products that may cause of several disease in human. Several virulence factors are involved in its ability to cause disease that one of the most important of them is the ability of the bacterium to produce biofilm. These bacteria are capable of producing polysaccharides and proteinaceous substances attached to the surfaces that leads to biofilm formation. In this study to assess the presence of S.aureus and distribution of genes encoding biofilm formation in the raw milk from Tehran city, a total of 99 raw milk samples was obtained from 4 big milk plants in the sterile conditions and assessed by conventional microbiological culturing methods and confirmed by PCR assayed. For this, nuc gene was used as the specific target sequence to detect S.aureus to identify the presence of fnbA, clfB, icaA, icaD genes which encode biofilm formation, the specific primers of every gene were exploited. Based on results of microbiological culturing and after confirming them with molecular ways, 4 isolates were detected as s.aureus (4.04%). The genes encoding biofilm formation, fnbA, cltB, & icaD were identified in all 4 isolates (100 %) and only one isolate (25%) contained icaD gene. Because the frequency of biofilm encoding genes separated from raw milk samples of Tehran city is considerable implementing hygienic principles is essential to control and preventing biofilm formation.