Swab Type, Moistening, and Preenrichment for Staphylococcus aureus on Environmental Surfaces

We compared five swabs, dry or premoistened and with or without preenrichment, to detect surface contamination with Staphylococcus aureus. Sensitivities varied based on swab type, as follows: 71.9% and 75% for rayon, 71.2% for cotton, 81.3% for polyester, and 53.2% for calcium alginate. Preenrichment improved sensitivity (80%, versus 61.3% for direct-plated specimens), as did premoistening (83.4%, versus 57.5% for dry swabs). All of the premoistened, preenriched swabs were positive.