Phenotypic study of the effects of environmental factors on the biofilm formation by staphylococcus aureus isolates

الملخص EN

The present study was designed to estimate the influence of different stress conditions (temperature, sodium chloride and glucose) on biofilm formation of Staphylococcus aureus.

Out of 39 S.

aureus including 22 isolates of methicillin resistant Staphylococcus aureus (MRSA) and 17 isolates of methicillin sensitive S.

aureus (MSSA) obtained from raw milk and subclinical mastitis samples, their phenotypic and genotypic resistance to methicillin were evaluated.

Each S.

aureus isolates was cultured in tryptic soy broth (TSB) with different concentrations of Glucose and Sodium chloride separately (2.

5%, 5%, and 10%), incubated at 37◦ C using a 96-well polystyrene microtiter plate.

These isolates also subjected to different degrees of incubation temperatures (25˚C, 37˚C and 42˚C) by using TSB with1% glucose.

The results revealed that the increase in the concentrations of sodium chloride or glucose enhanced the biofilm formation in both MRSA and MSSA.

On the other hand, the lower incubation temperature enhanced the biofilm formation in all isolates.

The results showed that the alterations in growth conditions stimulated the production of extracellular polymeric substances.