Molecular Analysis of Pathogenicity, Adhesive Matrix Molecules (MSCRAMMs) and Biofilm Genes of Coagulase-Negative Staphylococci Isolated from Ready-to-Eat Food

This paper provides a snapshot on the pathogenic traits within CoNS isolated from ready-to-eat (RTE) food. Eighty-five strains were subjected to biofilm and slime production, as well as biofilm-associated genes ( icaA, icaD, icaB, icaC, eno, bap, bhp, aap, fbe, embP and atlE ), the insertion sequence elements IS 256 and IS 257 and hemolytic genes. The results showed that the most prevalent determinants responsible for the primary adherence were eno (57.6%) and aap (56.5%) genes. The ica ADBC operon was detected in 45.9% of the tested strains and was correlated to slime production. Moreover, most strains carrying the ica ADBC operon simultaneously carried the IS 257 insertion sequence element. Among the genes encoding for surface proteins involved in the adhesion to abiotic surfaces process, atl E was the most commonly (31.8%) followed by bap (4.7%) and bhp (1.2%). The MSCRAMMs, including fbe and embp were detected in the 11.8% and 28.2% of strains, respectively. A high occurrence of genes involved in the hemolytic toxin production were detected, such as hla_yiD (50.6%), hlb (48.2%), hld (41.2%) and hla_haem (34.1%). The results of the present study revealed an unexpected occurrence of the genes involved in biofilm production and the high hemolytic activity among the CoNS strains, isolated from RTE food, highlighting that this group seems to be acquiring pathogenic traits similar to those of S. aureus , suggesting the need to be included in the routine microbiological analyses of food.