Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) strains isolated from dairy products: Relationship of ica-dependent/independent and components of biofilms produced in vitro

This study investigated the prevalence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in dairy products, and the relationship between polysaccharide intercellular adhesin (PIA) dependence/independence of MRSAs and the components of biofilms produced in vitro. Of 141 samples of dairy products collected, 26% were positive for S. aureus and 14% of S. aureus isolates were MRSA. MRSA biofilms (8.37-9.89 and 9.53-9.59 log(10) cfu cm(-2) for ica- positive and negative MRSA, respectively, in TSBNaCl on stainless steel) were characterised by epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and biofilm detachment was assessed with DNase I (32-44%) and proteinase K (18-32%) (p < 0.05). MRSA biofilms isolated from dairy products are a source of food contamination, thus a need to implement food safety systems and strategies for biofilm prevention and removal in the dairy industry. (C) 2021 Elsevier Ltd. All rights reserved.