Hand cream, fake nails implicated in outbreak

Synopsis: An outbreak of postoperative Serratia marcescens infections was traced to a scrub nurse whose hand cream, kept at home, was heavily contaminated with the organism. (See story in Hospital Infection Control, May 1995, p. 65.)

Source: Passaro DJ, et al. Postoperative Serratia marcescens wound infections traced to an out-of-hospital source. J Infect Dis 1997; 175:992-995.

Five of 31 cardiac surgery patients and one of 29 vascular surgery patients were infected with Serratia marcescens postoperatively over an approximately one-month period at a northern California hospital. One patient died. There had been no S. marcescens infections in cardiac or vascular surgery patients identified in at least the previous year. Epidemiological investigation found that, among a variety of associations, exposure to a scrub nurse (Nurse A) was significant in all stratified analyses. When stratified by exposure to Nurse A, however, exposure to ICU Nurse G and having surgery earlier in the work week remained significant.

Because of the outbreak, the hospital suspended cardiac surgery. However, soon thereafter a patient developed infection with S. marcescens after splenectomy. This patient was exposed to Nurse A, but not to Nurse G, and was not exposed to other risk factors identified in the initial analysis. Two sets of hand cultures from Nurse A were negative for S. marcescens, as were cultures from other staff and 600 hospital environment cultures. Nonetheless, Nurse A was strongly suspected as the source of the infections. As a consequence, culture specimens were obtained from her home, including cultures of water, moist surfaces, cosmetics, and soaps. All these cultures were negative for S. marcescens with the exception of an exfoliant cream kept in her shower, which contained more than 200,000 cfu/g.

Antibiotic susceptibility profiles of the case- isolates and the isolate from the cream were identical. Pulsed field gel electrophoresis and restriction-endonuclease analysis of the four available case-isolates and the exfoliant cream isolate also demonstrated apparent identity. Five other jars of the exfoliant cream from the same lot failed to yield S. marcescens on culture. Nurse A reported that she had used the cream throughout the outbreak period but only on weekends, usually on Sundays. She had not used it for more than two weeks before her first hand cultures. In addition, she had worn artificial fingernails during the entire outbreak period. The remaining exfoliant cream was discarded, and the artificial nails were removed; no further cases were subsequently identified.

Comment by Stan Deresinski, MD, FACP, clinical professor of medicine, Stanford University, associate chief of infectious diseases, Santa Clara Valley (CA) Medical Center.

The evidence strongly indicates that the source of this outbreak of postoperative infections due to S. marcescens was the jar of exfoliant cream, contaminated after purchase, in the shower stall of a scrub nurse. The clustering of cases early in the week was the result of her using the cream only on weekends when her hands were inoculated by it. Searching the home of a health care worker for the source of a nosocomial outbreak seems an extraordinary and unusual measure. The lines between hospital and community outbreaks have been blurring for additional reasons, as the hospital moves into the home in response to the profit demands of managed care organizations.

The use of artificial nails by Nurse A may have played an important contributory role in this outbreak. The authors point out studies indicating that hand carriage of gram-negative bacilli is higher after hand washing in the presence of artificial nails than in their absence, as well as a study indicating that nails with cracked or chipped fingernail polish carry increased numbers of bacteria (Pottingger J, et al. Am J Infect Cont 1989; 17:340-344; Wynd CW, et al. AORN J 1994; 60:799-805). In fact, the Association of Operating Room Nurses recommends that artificial nails not be worn by operating room personnel. Many hospitals have moved to ban their use by these health care workers.