INVESTIGATION OF BIOFILM FORMATION ABILITY OF COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM READY-TO-EAT MEAT

The aim of the study was to analyze the biofilm production capacity of coagulase-negative staphylococci (CNS) isolated from ready-to-eat meat products including pork ham, chicken cold cuts, pork sausage, salami and pork luncheon meat, sliced in the store to the consumer's specifications, along with determination of occurrence of the adhesion genes determining the polysaccharide production (icaA and ica) and collagen binding protein (cna).The isolates investigated included Staphylococcus equorum (28%), S. vitulinus (16%), S. carnosus (14%), S. succinus (11%), S. xylosus (11%), S. saprophyticus (9%), S. warneri (9%), S. haemolyticus (1%) and S. pasteuri (1%).The assessment of biofilm production capacity by staphylococci was made using crystal violet, whereas evaluation of the frequency of occurrence of genes was performed using the PCR.Among 81 CNS included in the current study, 84% showed ability to form biofilm in the experimental in vitro conditions.High biofilm capacity was demonstrated in 54% of strains, the average in 14%, and low in 16%, while the lack of biofilm production capacity was found in 16% of the tested strains.The icaA and icaD genes responsible for the production of extracellular polysaccharide adhesins were detected in 5% and 16% of strains respectively.The gene determining the formation of collagen binding protein (cna) was detected in 14% of strains.From the results obtained, it can be concluded that food is a source of coagulase-negative staphylococci capable of forming biofilm, which is referred to as clinically important virulent factor of these bacteria.