Correlation between resistance mechanisms in Staphylococcus aureus and cell wall and septum thickening

The aim of the present study is to examine cell wall and septum thickening of methicillin-sensitive (MSSA), methicillin-resistant (MRSA), and methicillin- and linezolid-resistant (MLRSA) isolates by transmission electron microscopy to correlate the association of resistance mechanisms with major changes in the morphology of membrane or septum. MSSA, MRSA, and MLRSA strains obtained from clinical samples of an outbreak that occurred in 2010 at the Intensive Care Unit of our Hospital were thawed and sown at 37°C in blood agar overnight. After that, they were washed, pelleted, and treated with a fixer solution. Pellets were dehydrated and finally embedded in resin. Transmission electron microscopy was used to characterize cell wall and septum thickening in all isolates. The comparison between the measurements obtained for each group was performed by a Kruskal-Wallis test and a post hoc Dunn-Bonferroni's pairwise comparison method. Differences in cell wall and septum thickness were statistically significant (