Biofilm formation and its relationship with the molecular characteristics of food-related methicillin-resistant Staphylococcus aureus (MRSA)

The capability to produce biofilm is an important persistence and dissemination mechanism of some foodborne bacteria. This paper investigates the relationship between some molecular characteristics (SCCmec, ST, spa-type, agr-type, cna, sarA, icaA, icaD, clfA, fnbA, fnbB, hla, hlb) of 22 food-related methicillin-resistant Staphylococcus aureus (MRSA) strains and their ability to form biofilm on stainless steel and polystyrene. Five (22.7%, 5/22) strains were able to synthesize biofilm on polystyrene, and one of these (4.5%, 1/22) strains was also able to synthesize biofilm on stainless steel. The largest amount of biofilm was formed on polystyrene by 2 MRSA strains isolated from cows’ milk, thus raising concern about the dairy industry. The majority of MRSA biofilm producers carried SCCmec type IVa, suggesting that the presence of SCCmecIVa and/or agr type III could be related to the ability to form biofilm. In conclusion, in order to achieve an acceptable level of food safety, Good Hygiene Practices should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA biofilm-producing strains in the food industry.