A five year outbreak of methicillin-susceptible Staphylococcus aureus phage type 53,85 in a regional neonatal unit

We identified a 5-year outbreak of a methicillin-susceptible Staphylococcus aureus (MSSA) strain, affecting 202 babies on a neonatal unit, by routine weekly phage typing all S. aureus isolates. Multiple staged control measure s including strict emphasis on hand hygiene, environmental and staff survei llance sampling, and application of topical hexachlorophane powder failed t o end the outbreak. S. aureus PT 53,85 (SA5385) was found on opened packs o f Stomahesive(R), used as a neonatal skin protectant. Only following the im plementation of aseptic handling of Stomahesive, and the use of topical mup irocin for staff nasal carriers of SA5385, and for babies colonized or infe cted with S. aureus, did the isolation rate of SA5385 decline. DNA fingerpr inting indicated that greater than or equal to 95% of SA5385 isolates were clonal. In vitro death rates of SA5385 on Stomahesive with human serum were significantly lower than on Stomahesive alone (P = 0.04), and on cotton sh eet with serum (P = 0.04), highlighting the potential of this material as a survival niche. Phage typing remains a valuable, inexpensive and simple me thod for monitoring nosocomial MSSA infection.