Outbreak of methicillin-resistant Staphylococcus aureus colonization and infection in a neonatal intensive care unit epidemiologically linked to a healthcare worker with chronic otitis.
OBJECTIVE
To describe the investigation and interventions necessary to contain an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in a neonatal intensive care unit (NICU).


METHODS
Retrospective case finding that involved prospective performance of surveillance cultures for detection of MRSA and molecular typing of MRSA by repetitive-sequence polymerase chain reaction (rep-PCR).


METHODS
Level III NICU in a tertiary care center.


METHODS
Three neonates in a NICU were identified with MRSA bloodstream infection on April 16, 2004. A point prevalence survey identified 6 additional colonized neonates (attack rate, 75% [9 of 12 neonates]). The outbreak strain was phenotypically unusual.


METHODS
Cohorting and mupirocin therapy were initiated for neonates who had acquired MRSA during the outbreak. Contact precautions were introduced in the NICU, and healthcare workers (HCWs) were retrained in cleaning and disinfection procedures and hand hygiene. Noncolonized neonates and newly admitted patients had surveillance cultures performed 3 times per week.


RESULTS
Two new colonized neonates were identified 1 month later. HCW X, who had worked in the NICU since June 2003, was identified as having chronic otitis. MRSA was isolated from cultures of swab specimens from HCW X's ear canal and nares. HCW X was epidemiologically linked to the outbreak. Molecular typing (by rep-PCR) confirmed that the isolates from HCW X and from the neonates were more than 90% similar. Retrospective review of NICU isolates revealed that the outbreak strain was initially cultured from a neonate 2 months after HCW X began working on the unit. The epidemic strain was eradicated after removing HCW X from patient care in the NICU.


CONCLUSIONS
An outbreak of MRSA colonization and infection in a NICU was epidemiologically linked to a HCW with chronic otitis externa and nasal colonization with MRSA. Eradication was not achieved until removal of HCW X from the NICU. Routine surveillance for MRSA may have allowed earlier recognition of the outbreak and is now standard practice in our NICU.
Bertin
Mary L
ML
Department of Infection Control and Epidemiology, Division of Nursing, The Cleveland Clinic, Cleveland, OH 44195, USA. Bertinm@ccf.org
Vinski
Joan
J
Schmitt
Steven
S
Sabella
Camille
C
Danziger-Isakov
Lara
L
McHugh
Michael
M
Procop
Gary W
GW
Hall
Geraldine
G
Gordon
Steven M
SM
Goldfarb
Johanna
J
D016470:Bacteremia / Q000382:microbiology; D002908:Chronic Disease; D004196:Disease Outbreaks; D005260:Female; D006282:Health Personnel; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D017053:Infection Control / Q000379:methods; D017757:Infectious Disease Transmission, Professional-to-Patient; D007363:Intensive Care Units, Neonatal; D008297:Male; D016106:Methicillin Resistance; D009668:Nose Diseases / Q000150:complications* / Q000382:microbiology; D009820:Ohio; D010032:Otitis Externa / Q000150:complications* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011159:Population Surveillance; D011446:Prospective Studies; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000150:complications / Q000635:transmission*; D013211:Staphylococcus aureus / Q000302:isolation & purification