In vitro biofilm production by Staphylococcus spp. strains isolated from finger-foods and snacks

Abstract

Staphylococcus aureus is one of the most important food-borne pathogens, and although Brazilian Sanitation Surveillance Agency (ANVISA) does not specifically regards for coagulase-negative Staphylococcus (CNS) isolation from foods, it is known that this group of bacteria possesses genes associated with biofilm formation and enterotoxins production. In this context, the present study aimed at identifying the S. aureus and CNS in finger-foods and snacks samples, and to evaluate the ability of these strains to produce biofilm in vitro by means of two methodologies: Congo Red agar and polystyrene microplates cultures. Twenty-two staphylococcal isolates belonging to eight species were obtained from 122 finger-foods, sandwiches and ready-to-eat (RTE) food products. S. aureus, S. warneri and S. haemolyticus were the most frequent isolates. Biofilm production by Staphylococcus spp. was observed in seven (31.8 %) isolates by Congo Red agar technique and three (13.6 %) by polyestirene microplate methodology. There was no positive isolate biofilm producer by both methodologies. Despite the low number of isolates, a concordance of 59.1 % between the tests was found. The ability to produce biofilm is an important virulence factor in Staphylococcus spp., and it can support to define the role of CNS as food-borne pathogen.