Emergence of resistant staphylococci on the hands of new graduate nurses

Abstract

Objective: To describe the aerobic microbial flora on the hands of experienced and new graduate nurses over time.

Design: A prospective cohort design that examined the relationship between duration of employment in an intensive care unit (ICU) and the microbial flora on the hands of experienced and new graduate nurses during a 23-month period.

Setting: A 50-bed, level III-IV neonatal ICU in New York City.

Participants: Twelve experienced nurses and 9 new graduate nurses working full time in the NICU.

Intervention: One hundred fifty samples were obtained from the clean, dominant hands of the nurses. Cultures were performed at baseline and then quarterly for each experienced and new graduate nurse. Baseline and final cultures of Staphylococcus epidermidis were further examined using pulsed-field gel electrophoresis.

Results: At baseline, a significantly larger proportion of the experienced nurses had methicillin-resistant, coagulase-negative staphylococci isolated from their hands compared with the new graduate nurses (95% and 33%, respectively; P = .0004). For a second culture, performed 1 to 4 months later, there were no longer significant differences between the two groups (82% and 54%, respectively; P = .12). By the last culture, all staphylococcal isolates were methicillin resistant in both groups of nurses; 3 were methicillin-resistant S. aureus.

Conclusions: Colonization with methicillin-resistant staphylococci occurred after brief exposure to the hospital environment, despite the use of antiseptic hand hygiene agents. Furthermore, at final culture, the two groups shared one dominant hospital-acquired strain of S. epidermidis.

FIGURE

Pulsed-field gel electrophoresis of Staphylococcus epidermidis isolates from the first and last cultures of two experienced nurses and three new graduate nurses. Lane 1 = the lambda marker; lane 2 = first culture for new graduate nurse 1 showing clone B; lane 3 = last culture for new graduate nurse 1 showing clone A; lane 4 = first culture for new graduate nurse 2 showing clone C; lane 5 = last culture for new graduate nurse 2 showing clone A; lane 6 = first culture for new nurse graduate 3 showing clone D; lane 7 = last culture for new graduate nurse 3 showing clone A₃; lane 8 = first culture for experienced nurse 1 showing clone A₃; lane 9 = last culture for experienced nurse 1 showing clone A; lane 10 = first culture for experienced nurse 2 showing clone E; and lane 11 = last culture for experienced nurse 2 showing clone A.