Frequency of binding genes in Staphylococcus aureus isolated from dairy products in Shahrekord. Binding genes of Staphylococcus aureus in dairy products

Subject Areas : Food Microbial Contamination

Rasul Pajohesh ¹ , Elahe Tajbakhsh ² , Hassan Momtaz ³ , Ebrahim Rahimi ⁴

1 - Department of Microbiology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad
2 - Department of Microbiology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
3 - Department of Microbiology, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
4 - Department of Food Hygiene, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.

Received: 2022-10-30 Accepted : 2023-01-28 Published : 2023-03-21

Keywords: Biofilm, Staphylococcus aureus, dairy products, Adhesion genes,

Abstract :

Staphylococcus aureus is an opportunistic pathogen in humans and animals, which can cause contaminating dairy products. In this research, 250 traditional dairy products, including butter, yogurt, cheese, curd, and cream, were prepared from different parts of Shahrekord city and transported to the microbiology laboratory of Shahrekord Azad University in sterile containers with ice. The isolation of Staphylococcus aureus bacteria was done according to standard protocols and molecular methods. Genetic evaluation of biofilm was done by PCR method to detect the most common biofilm coding genes (icaA, icaB, icaC, icaD, bap, fnbA, fnbB, clfB, clfA). From the total of 250 examined samples, 50 samples (20%) were positive for Staphylococcus aureus. Contamination was reported in 26% of curd, 24% of butter, 22% of cheese, 16% of cream, and 12% of yogurt. The frequency of the mentioned genes was reported as 74%, 68%, 64%, 76%, 30%, 96%, 90%, 32% and 28% respectively. In the microtiter plate method, biofilm reaction was observed in 30 isolates (60%), strong biofilm was observed in 20 isolates (66.66%), and weak biofilm was observed in 10 isolates (33.33%). No biofilm reaction was observed in 5 isolates (16.66%). Based on Fisher's exact test, a statistically significant relationship was reported between the studied genes and strong and moderate biofilm reaction.