A new microbiological problem in intensive care units: Environmental contamination by MRSA with reduced susceptibility to glycopeptides

The present study evaluated the percentage of methicillin-resistant Staphylococcus aureus strains with reduced susceptibility to glycopeptides in four intensive care units (ICU) by means of environmental sampling of air and representative surfaces. The total bacterial count was taken and possible S. aureus strains were subsequently isolated. To assess methicillin resistance, an antibiogram was performed on the colonies that were positive to the coagulase test. A standard E-test was then carried out on the colonies that developed, in order to evaluate glycopeptide resistance, and any heterogeneous resistance was confirmed by means of a macromethod E-test.The antibiogram performed on the colonies of S. aureus revealed that 85.7% of all air samples were positive for MRSA, and that 64.3% of all the samples proved to be heterogeneously resistant to glycopeptides. Methicillin resistance was recorded in 41.0% of surface samples, and 32.5% of all samples proved positive for hGISA.