A prolonged outbreak of Pseudomonas aeruginosa in a neonatal intensive care unit: did staff fingernails play a role in disease transmission?
OBJECTIVE
To describe an outbreak of Pseudomonas aeruginosa bloodstream infection (BSI) and endotracheal tube (ETT) colonization in a neonatal intensive care unit (NICU), determine risk factors for infection, and make preventive recommendations.


METHODS
A 15-month cohort study followed by a case-control study with an environmental survey and molecular typing of available isolates using pulsed-field gel electrophoresis.


METHODS
Neonates in the NICU of a university-affiliated children's hospital.


METHODS
Improved hand washing and restriction of use of long or artificial fingernails.


RESULTS
Of 439 neonates admitted during the study period, 46 (10.5%) acquired P aeruginosa; 16 (35%) of those died. Fifteen (75%) of 20 patients for whom isolates were genotyped had genotype A, and 3 (15%) had genotype B. Of 104 healthcare workers (HCWs) from whom hand cultures were obtained, P aeruginosa was isolated from three nurses. Cultures from nurses A-1 and A-2 grew genotype A, and cultures from nurse B grew genotype B. Nurse A-1 had long natural fingernails, nurse B had long artificial fingernails, and nurse A-2 had short natural fingernails. On multivariate logistic regression analysis, exposure to nurse A-1 and exposure to nurse B were each independently associated with acquiring a BSI or ETT colonization with P aeruginosa, but other variables, including exposure to nurse A-2, were not.


CONCLUSIONS
Epidemiological evidence demonstrated an association between acquiring P aeruginosa and exposure to two nurses. Genetic and environmental evidence supported that association and suggested, but did not prove, a possible role for long or artificial fingernails in the colonization of HCWs' hands with P aeruginosa. Requiring short natural fingernails in NICUs is a reasonable policy that might reduce the incidence of hospital-acquired infections.
Moolenaar
R L
RL
Acute Disease Division, Oklahoma State Department of Health, Oklahoma City, USA.
Crutcher
J M
JM
San Joaquin
V H
VH
Sewell
L V
LV
Hutwagner
L C
LC
Carson
L A
LA
Robison
D A
DA
Smithee
L M
LM
Jarvis
W R
WR
D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D004866:Equipment Contamination / Q000706:statistics & numerical data; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D017053:Infection Control; D017757:Infectious Disease Transmission, Professional-to-Patient / Q000706:statistics & numerical data*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation; D016015:Logistic Models; D008297:Male; D009262:Nails / Q000382:microbiology*; D009741:Nursing Staff, Hospital / Q000706:statistics & numerical data*; D009825:Oklahoma / Q000453:epidemiology; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics; D012189:Retrospective Studies; D012307:Risk Factors; D012703:Serotyping; D000078329:Workforce
D004269:DNA, Bacterial