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A prolonged outbreak of Pseudomonas aeruginosa in a neonatal intensive care unit: did staff fingernails play a role in disease transmission?


OBJECTIVES: 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.

DESIGN: 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.

SETTING AND PATIENTS: Neonates in the NICU of a university-affiliated children’s hospital.

INTERVENTIONS: 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.

CONCLUSION: 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 RL, Crutcher JM, San Joaquin VH, Sewell LV, Hutwagner LC, Carson LA, Robison DA, Smithee LM, Jarvis WR

Infect Control Hosp Epidemiol 2000 Feb;21(2):80-5

PMID: 10697282