High Frequency of biofilm related genes (icaD, fnbA, icaA and clfA) among Staphylococcus aureus isolated from bovine with subclinical mastitis

Background and aim: Regarding to the importance of Staphylococcus aureuscolonization in bovine mastitis and the role of biofilm in its pathogenesis, the aim of the present study were to assessment of biofilm production and identification of biofilm related genes among S. aureus isolated from bovine with subclinical mastitis. Materials and Methods: In this cross-sectional study, a total of 502 milk samples collected from bovine with subclinical mastitis in Boyerahmad and Dena townships. After isolation of bacteria, detection of nucA gene by PCR method was used for final confirmation of S. aureus. Congo Red Agar plate was used for assessment of biofilm production.PCR method was used for detection oficaA, icaD, fnbA,clfA, cna and bap genes. Data were analyzed by SPSS software version 15 and chi-square test.  Results: Totally 80(15.9%) S. aureus isolated from milk samples, which among them 55(68.7%) were biofilm producer. The icaD gene was the most prevalent gene detected in 87.5% of isolates, while bap with lowest frequency identified in 4 (5%) isolates. Significant association were observed between biofilm production and presence of icaD(p=0.0001),  icaA(p=0.003), fnbA(p=0.0001) and clfA(p=0.0001). Conclusion: Considering the important role of biofilm in development of antibiotic resistance and high frequency of biofilm producer isolates, it is considered as an alarm. Hence biofilm production helps to bacterial colonization and pathogenesis can causes economical and healthy losses on community.