Biofilm-producing ability of Staphylococcus spp isolated from different foodstuff products

In recent times, microbial-biofilm contamination has attracted considerable attention to the food industry. Pathogenic microorganisms can attach to food surfaces, grow on them, and form biofilm that cause an increase in the food safety risk. The mechanisms of biofilm formation have become an important issue in the food-processing industry, therefore, the aim of this study is to determine the biofilm formation and profiles of genes involved in biofilm production of staphylococci isolated from various foodstuff products.

This cross-sectional study was conducted at some grocery stores and confectionaries from September 2015 to October 2016 in different areas of Isfahan, Iran. Staphylococcus spp were isolated from different foodstuff samples including sweet pastries, cakes and similar baked goods, dairy products such as cheese and yogurt, meat products such as sausages, and hamburgers. Standard microbiological methods were used for identification of Staphylococcus spp isolates. Antibiotic susceptibility pattern was determined by the disc diffusion method and icaA/icaD genes have been investigated as PCR target because of their role in the expression of intercellular adhesions involved in biofilm formation by S. aureus.

From a total of 194 different foodstuffs samples, 84 Staphylococcus spp were isolated. Out of the 84 Staphylococcus isolates, 95.2% (80/84) were positive to the ability of biofilm formation. Overall, 35.7% (30/84) and 26.2% (22/84) of Staphylococcus spp isolates were positive for icaA and icaD genes, respectively.

The results of the present study indicate that the remarkable rate of biofilm formation with the emergence of antibiotic resistance still remains a significant risk for the food safety, especially in foodstuff samples.