A rapid PCR method for the detection of slime-producing strains of Staphylococcus epidermidis and S-aureus in periprosthesis infections

In periprosthesis tissues, Staphylococcus epidermidis produces extracellula r polysaccharide slime. Recently it has been shown that S. aureus also prod uces slime and that both S. epidermidis and S. aureus contain the ica opero n responsible for slime production. In the operon, icaA encodes for N-acety lglu taminyltransferase, the enzyme for polysaccharide synthesis. However, co-expression of icaA and icaD is required for full slime synthesis. The sl ime-producing strains of both S. epidermidis and S. aureus are more virulen t and are responsible for severe postsurgical or periprosthesis infections. The authors describe a simple, rapid, and reliable polymerase chain reacti on method to detect icaA and icaD. The method was applied to the detection of ica genes on two reference strains, 15 strains each of S. epidermidis an d S. aureus from periprosthesis infections and 10 strains from the skin and mucosa of healthy volunteers. icaA and icaD were detectable only in slime- producing strains (tested for slime production on Congo Red agar), and neve r in nonslime-producing ones. This method is a straightforward way of detec ting the slime-producing ability by S. epidermidis and S. aureus. In clinic al specimens this polymerase chain reaction method enables rapid diagnosis of virulent slime-producing strains with respect to the traditional culture method on Congo Red agar, which requires much more time. Rapid identificat ion of the virulent properties of the bacterial strain responsible for a st aphylococcal infection is crucial for deciding treatment.