Detection of icaA and icaD genes and biofilmformation in Staphylococcus spp. isolated from urinary catheters at the University Hospital of Tlemcen (Algeria)

Staphylococcus spp. is a major cause of infections associated with urinary catheterization and other medical devices. Biofilm formation is an important step in the pathogenesis of these Staphylococci and depends on the expression of the icaADBC operon involved in the synthesis of a polysaccharide intercellular adhesion. In this study, forty-four (44) Staphylococcus spp. obtained from urinary catheters at the University Hospital of Tlemcen (North-West Algeria) were analyzed to investigate the presence or absence of the intercellular adhesion icaA and icaD genes, using the polymerase chain reaction (PCR). Phenotypic biofilm formation was examined by tissue culture plate (TCP) and Congo red agar (CRA) methods. Seventeen (17) of 44 isolates were shown to carry ica-specific DNA, 18 produced slime on CRA plates but only eight produced biofilm spontaneously on the polystyrene surfaces, under normal growth conditions. Upon induction by sugar, biofilm formation could be stimulated in seven (7) of nine (9)ica positive. Biofilm-negative isolates indicated that the icaADBC expression was down-regulated in these strains. Staphylococcus strains isolated from urinary catheters showed high levels of resistance to penicillin (98%) and gentamicine (75%). The data obtained shows the important role of ica-genes, the phenotypic variability of biofilm formation and the multi-resistance to antibiotics as virulence factors of staphylococcus spp. from urinary catheters.It confirms the complexity and diversity of regulation mechanisms implicated in biofilm formation.