ABSTRACT
It
is well known that biofilm formation by pathogenic staphylococci on
implanted medical devices leads to “chronic polymer-associated
infections.” Bacteria in these biofilms are more resistant to
antibiotics and the immune defense system than their planktonic
counterparts, which suggests that the cells in a biofilm have altered
metabolic activity. To determine which genes are up-regulated in
Staphylococcus aureus biofilm cells, we carried out a
comparative transcriptome analysis. Biofilm growth was simulated on
dialysis membranes laid on agar plates. Staphylococci were cultivated
planktonically in Erlenmeyer flasks with shaking. mRNA was isolated at
five time points from cells grown under both conditions and used for
hybridization with DNA microarrays. The gene expression patterns of
several gene groups differed under the two growth conditions. In
biofilm cells, the cell envelope appeared to be a very active
compartment since genes encoding binding proteins, proteins involved in
the synthesis of murein and glucosaminoglycan polysaccharide
intercellular adhesin, and other enzymes involved in cell envelope
synthesis and function were significantly up-regulated. In addition,
evidence was obtained that formate fermentation, urease activity, the
response to oxidative stress, and, as a consequence thereof, acid and
ammonium production are up-regulated in a biofilm. These factors might
contribute to survival, persistence, and growth in a biofilm
environment. Interestingly, toxins and proteases were up-regulated
under planktonic growth conditions. Physiological and biochemical tests
for the up-regulation of urease, formate dehydrogenase, proteases, and
the synthesis of staphyloxanthin confirmed the microarray
data.
Cell Surface Expression of Nrg1 Protein in Candida auris
