Using a novel method, investigators revealed marked heterogeneity in healthcare worker interactions and in the potential consequences of their hand hygiene.
Attempts to understand disease transmission in healthcare settings have generally assumed that healthcare workers (HCWs) move and interact uniformly. However, observational studies have suggested the possibility of peripatetic “superspreaders” who have greater-than-average mobility and interactivity — and thus more opportunity to spread infection. In a recent study conducted in the medical intensive care unit of a university hospital, researchers assessed this possibility.
The researchers used small electronic badges worn by HCWs, together with fixed-position beacons, to determine patterns of HCW movement and interactions within this 20-bed unit. They then used these data to mathematically model the effect of HCW hand hygiene on pathogen transmission.
During the 48-hour period of analysis, the average number of contacts (HCW–HCW and HCW–patient) per HCW was 80.1 for day shifts and 76.1 for night shifts. However, a few HCWs were responsible for a disproportionately large share of the contacts. Modeling the effect of hand-hygiene activity on disease transmission showed that spread of a pathogen would be significantly greater with noncompliance of a few high-contact staff members than with noncompliance of an equal number of low-contact workers.
Comment: Hand hygiene is a central tenet of infection control, yet since the original work of Semmelweis, there has been relatively little research on the direct effects of hand-hygiene behavior on disease transmission. Hornbeck and colleagues have provided new insights into HCW contacts, which can help us to understand the role of hand hygiene in preventing nosocomial spread of pathogens and thus to develop more-sophisticated approaches for improving its efficacy.