Biofilm formation by staphylococcus aureus isolation from atopic dermatitis patients on defined lewis types saliva

الملخص EN

Bacteria adherence and biofilm formation vary depending on strain of microorganism as well asthe substrate .Here ,we evaluated the ability of different isolates of Staphylococcus aureus (S.

aureus) ,isolated.

from atopic dermatitis patients skin and stool to form biofilm on different Lewis types saliva ,including Le (a) , (b) ,(c) and Le a+b+ saliva.

S.

aureus isolates were cultured on tryptose soy broth .The bacteria were used to form biofilm on 96- well flat bottom Microtitration plate that was coated with the respective , optimally diluted,processed saliva of Lewis blood groups (a),(b),(c) and Le a+b+ .The intensity of biofilm formation was assessed by measuring the biofilm – associated optical density reading of bacterial bound dye.

The results indicated a superior ability of biofilm formation on Lewis(a) saliva type .The highest binding gave a mean of 1.25 ± 0.39 compared to biofilm formation on non – coated wells that showed a mean of 0.23 ± 0.016(P=0.01 , CL= 0.390 – 1.635).

On the other hand however, a variable degree of binding to Le(b) saliva was demonstrated for the isolates.

The isolates didn’t demonstrate binding on Lea-b-(Lec) and Le a+b+ -(Led) saliva.

We conclude that biofilm formation on Lewis types saliva of the atopic dermatitis bacterial isolates requires Le(a) in a ligand – receptor based system for biofilm establish- ment.