Serratia marcescens outbreak associated with extrinsic contamination of 1% chlorxylenol soap.
OBJECTIVE
To determine risk factors for Serratia marcescens infection or colonization, and to identify the source of the pathogen and factors facilitating its persistence in a neonatal intensive-care unit (NICU) during an outbreak.


METHODS
Retrospective case-control study; review of NICU infection control policies, soap use, and handwashing practices among healthcare workers (HCWs); and selected environmental cultures.


METHODS
A university-affiliated tertiary-care hospital NICU.


METHODS
All NICU infants with at least one positive culture for S marcescens during August 1994 to October 1995. Infants who did not develop S marcescens infection or colonization were selected randomly as controls.


RESULTS
Thirty-two patients met the case definition. On multivariate analysis, independent risk factors for S marcescens infection or colonization were having very low birth weight (< 1,500 g), a patent ductus arteriosus, a mother with chorioamnionitis, or exposure to a single HCW. During January to July 1995, NICU HCWs carried their own bottles of 1% chlorxylenol soap, which often were left standing inverted in the NICU sink and work areas. Cultures of 16 (31%) of 52 samples of soap and 1 (8%) of 13 sinks yielded S marcescens. The 16 samples of soap all came from opened 4-oz bottles carried by HCWs. DNA banding patterns of case infant, HCW soap bottle, and sink isolates were identical.


CONCLUSIONS
Extrinsically contaminated soap contributed to an outbreak of S marcescens infection. Very-low-birth-weight infants with multiple invasive procedures and exposures to certain HCWs were at greatest risk of S marcescens infection or colonization.
Archibald
L K
LK
Hospital Infections Program, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia 30333, USA.
Corl
A
A
Shah
B
B
Schulte
M
M
Arduino
M J
MJ
Aguero
S
S
Fisher
D J
DJ
Stechenberg
B W
BW
Banerjee
S N
SN
Jarvis
W R
WR
D000891:Anti-Infective Agents, Local; D016022:Case-Control Studies; D016358:Contact Tracing; D003428:Cross Infection / Q000635:transmission*; D004196:Disease Outbreaks; D005260:Female; D006797:Housekeeping, Hospital; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D016868:Serratia Infections / Q000635:transmission*; D012706:Serratia marcescens; D012915:Soaps; D014992:Xylenes
D000891:Anti-Infective Agents, Local; D012915:Soaps; D014992:Xylenes; C007027:chloroxylenol