Screening HCWs, Decolonization of MRSA Carriers Unlikely to Reduce Nosocomial Spread of MRSA

Control of methicillin-resistant Staphylococcus aureus (MRSA) transmission has been unsuccessful in many hospitals. Recommended control measures include isolation of colonized patients, rather than decolonization of carriage among patients and/or healthcare workers, yet the potential effects of such measures are poorly understood.
 
Gurieva, et al. (2012) describe a stochastic simulation model in which healthcare workers can transmit MRSA through short-lived hand contamination, or through persistent colonization. Hand hygiene interrupts the first mode, decolonization strategies the latter. The researchers quantified the effectiveness of decolonization of patients and healthcare workers, relative to patient isolation in settings where MRSA carriage is endemic (rather than sporadic outbreaks in non-endemic settings caused by healthcare workers).
 
Patient decolonization is the most effective intervention and outperforms patient isolation, even with low decolonization efficacy and when decolonization is not achieved immediately. The potential role of persistently colonized healthcare workers in MRSA transmission depends on the proportion of persistently colonized healthcare workers and the likelihood per colonized healthcare worker to transmit. As a stand-alone intervention, universal screening and decolonization of persistently colonized healthcare workers is generally the least effective intervention, especially in high endemicity settings. When added to patient isolation, such a strategy would have maximum benefits if few healthcare workers cause a large proportion of the acquisitions.

The researchers conclude that in high-endemicity settings regular screening of healthcare workers followed by decolonization of MRSA-carriers is unlikely to reduce nosocomial spread of MRSA unless there are few persistently colonized healthcare workers who are responsible for a large fraction of the MRSA acquisitions by patients. In contrast, decolonization of patients can be very effective. Their research is published in BMC Infectious Diseases.

Reference: Gurieva TV, Bootsma MCJ and Bonten MJM. Decolonization of patients and healthcare workers to control nosocomial spread of methicillin-resistant Staphylococcus aureus: a simulation study. BMC Infectious Diseases 2012, 12:302 doi:10.1186/1471-2334-12-302