COMPARATIVE-ANALYSIS OF A BIOFILM-FORMING STAPHYLOCOCCUS-EPIDERMIDIS STRAIN AND ITS ADHESION-POSITIVE, ACCUMULATION-NEGATIVE MUTANT M7

We have isolated a stable slime-negative mutant, M7, from the wild-typ e Staphylococcus epidermidis RP62A by mitomycin mutagenesis. Besides i ts inability to produce slime in the test tube this mutant differed al so in two other properties from its parent strain: it lacked the abili ty to accumulate on a surface, and it did not produce a 115 kDa and a 18 kDa extracellular protein. In all other tested properties such as i nitial adherence, growth rate, cell-wall composition, surface characte ristics, DNA restriction profile, the presence of a 29 kb antibiotic r esistance plasmid, and antimicrobial susceptibility profile, M7 was in distinguishable from its wild-type. The mutant is an important basis f or further study of the pathogenesis of polymer-associated S. epidermi dis infections.