Dear weam, what is your aim? to identify virulence factor genes? biofilm forming ability or biofilm related genes?

Dear Mert..thanks for your interest.. actually we are trying to identify virulence factors that this bacteria are using during invasion upon ocular infections...not on the genetic level...regards 

Dear Weam, simply you can use microplate test to determine biofilm formation of your S. aureus strains.

Best regards.

Dear Mert..well thank you for your advice.. do you have an article or any accomplished work either for you or your colleagues related to this subject.. I will be thankful.. 

regards

Dear Weam, you can follow the protocol described in the paper of Dr. Stepanovic. We also carry out biofilm test using this protocol.

Best regards.

Stepanovic, S., Djukic, V., Djordjevic, V., Djukic, S., 2003. Influence of the incubation

atmosphere on the production of biofilm by staphylococci. Clinical Microbiology

and Infection 9, 955–958.

Dear Weam,

Microtiter Dish Biofilm Assay is commonly used to assess the quantity of biofilm in different kinds of bacteria.

The article below includes also a short video explaining procedures.

However, there are some aspects that you should pay attention:

1. medium used for growth - TSB is common

2. additional supplementation with glucose

3. surface of the microtiter dish used, I have good experience with plates for tissue cell culture, their surface is modified to support adhesion and growth of cells, and it works also for bacteria. I was using Nunclon™ Delta Surface from Thermo Fisher Scientific.

Regards

Jan

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182663/

To identify if adhesion is a virulent factor first you charachterise properties important for adhesion, such as motility, swarming, aggregation and adhesion in first hours or first 24 h. There are several protocols available. Regarding the adhesion I suggest you to analyse bacerial biomass (christal violet), bacterial culturability (CFU/ml of adhered cells) and viability of adhered cells (using different dyes, such as INT).

Howevere after you know what is the range of adhesion, you can focuse on biofilm formation and properties suhc as quorum sensing, the component of expolisahcarides and biofilm formation deterination .For the last you incubate the plate for 2,3,4,5 days and in each day you characterize the biofilm using biomase, culturability and viability of the cells in biofilm.

In this way you get the informations about the ahdesion, biofilm formation and biofilm stabiltiy - all important propertis for further contamination and infection, consequenlty important virulence factor.

Some of the publications with methods and protocols:

Chapter Antimicrobial Natural Products Against Campylobacter

Article Antiadhesion activity of juniper (Juniperus communis L.) pre...

Article Effects of natural antimicrobials on bacterial cell hydropho...

Article Reduced contamination and infection via inhibition of adhesi...

Article Anti-Campylobacter activity of resveratrol and an extract fr...

Article Attenuation of Adhesion, Biofilm Formation and Quorum Sensin...

Article Anti-adhesion activity of thyme (Thymus vulgaris L.) extract...

Dear Anja Klancnik thanks very much for your precious answer...hope always scientific cooperation.