Researchers Explore How Contaminated Surfaces Transmit Nosocomial Pathogens

In a review article in the latest issue of Infection Control and Hospital Epidemiology, researchers Jonathan Otter, Saber Yezli and Gary French acknowledge that while outbreaks of infection have been associated with contaminated hospital equipment and environmental surfaces, "the degree to which ongoing contamination of the surface environment contributes to the development of healthcare-associated infections is unclear, and approaches to control are uncertain." They add further, "Hospital patients shed pathogens into their surrounding environments, but there is debate over the importance of the resulting surface contamination as a source for subsequent transmission."

In the article, Otter, et al. review evidence that nosocomial pathogens are shed by patients and can contaminate hospital surfaces at concentrations sufficient for transmission, can survive for extended periods, can persist despite attempts to disinfect or remove them, and can be transferred to the hands of healthcare providers. They also review evidence that improved environmental hygiene can help to bring outbreaks under control and reduce endemic nosocomial transmission.

The researchers conclude, "The historical perspective that contaminated surfaces contribute negligibly to nosocomial transmission has been reevaluated in light of new information. There is now compelling evidence that contaminated surfaces make an important contribution to the epidemic and endemic transmission of C. difficile, VRE, MRSA, A. baumannii, and P. aeruginosa and to the epidemic transmission of norovirus. However, few studies have quantified the link between contaminated surfaces and the risk of transmission. This is in part due to the difficulties in conducting research in this area because of the multifaceted nature of nosocomial transmission. In addition, the widespread view that contaminated surfaces are relatively unimportant in transmission has meant that fundholders and administrators have not commissioned research in this area until relatively recently. There is now sufficient evidence to support further studies in this area to identify the best methods of achieving and maintaining clean hospitals and to evaluate the cost and effectiveness of such interventions with respect to reducing the incidence of hospital-associated infections. In particular, there is a need to conduct large, high-quality prospective controlled trials to identify interventions that significantly reduce surface contamination and transmission."

Reference: Otter JA, Yezli S and French GL. The Role Played by Contaminated Surfaces in the Transmission of Nosocomial Pathogens. Infect Control Hosp Epidem. Vol. 32, No. 7. Pp. 687-699. July 2011.