The use of typing methods and infection prevention measures to control a bullous impetigo outbreak on a neonatal ward

BACKGROUND: We describe an outbreak of Bullous Impetigo (BI), caused by a (methicillin susceptible, fusidic acid resistant) Staphylococcus aureus (SA) strain, spa-type t408, at the neonatal and gynaecology ward of the Jeroen Bosch hospital in the Netherlands, from March-November 2011. METHODS: We performed an outbreak investigation with revision of the hygienic protocols, MSSA colonization surveillance and environmental sampling for MSSA including detailed typing of SA isolates. Spa typing was performed to discriminate between the SA isolates. In addition, Raman-typing was performed on all t408 isolates. RESULTS: Nineteen cases of BI were confirmed by SA positive cultures. A cluster of nine neonates and three health care workers (HCW) with SA t408 was detected. These strains were MecA(-), PVL(-), Exfoliative Toxin (ET)A(-), ETB(+), ETAD(-), fusidic acid-resistant and methicillin susceptible. Eight out of nine neonates and two out of three HCW t408 strains yielded a similar Raman type. Positive t408 HCW were treated and infection control procedures were reinforced. These measures stopped the outbreak. CONCLUSIONS: We conclude that treatment of patients and HCW carrying a predominant SA t408, and re-implementing and emphasising hygienic measures were effective to control the outbreak of SA t408 among neonates.