Estimated levels of microbial burden on hospital environmental surfaces vary substantially among published studies. Cultures obtained during a cluster-controlled crossover trial of a quaternary ammonium (Quat) disinfectant versus an improved hydrogen peroxide (IHP) disinfectant provided additional data on the amount of microbial burden on selected surfaces.

RODAC plates containing D/E neutralizing agar were used to sample a convenience sample of 5–8 high-touch surfaces in patient rooms on 2 medical wards, an intensive care unit, and a step-down unit at a large hospital. Before routine daily cleaning, samples were obtained in varying rooms over an 11-month period. RODAC plates (1 per surface sampled) were incubated for 72 hours, and aerobic colony counts per plate (ACCs) were determined. Statistical analysis was used to determine the potential impact on ACCs of study period, cleaning compliance rate, disinfectant used, ward, surface sampled, and isolation room status.

Overall, 590 cultures were obtained on Quat wards and 589 on IHP wards. Multivariable regression analysis revealed that mean ACCs differed significantly by site (P < .001), type of ward (P < .001), isolation room status (P = .039), and study period (P = .036). The highest mean ACCs per RODAC plate were on toilet seats (112.8), bedside rails (92.0), and bathroom grab bars (79.5).

The combination of factors analyzed revealed that estimating microbial burden is complex and is affected by multiple factors. Additional studies should evaluate individual sites, ward types, cleaning and disinfection practices, and isolation room status.

The effectiveness of alcohol-based hand rub (ABHR) is correlated with drying time, which depends on the volume applied. Evidence suggests that there is considerable variation in the amount of ABHR used by healthcare providers.

We sought to identify the volume of ABHR preferred for use by nurses.

A prospective observation study was performed in 8 units at a tertiary-care hospital. Nurses were provided pocket-sized ABHR bottles with caps to record each bottle opening. Nurses were instructed to use the volume of ABHR they felt was best. The average ABHR volume used per hand hygiene event was calculated using cap data and changes in bottle mass.

In total, 53 nurses participated and 140 nurse shifts were analyzed. The average ABHR dose was 1.09 mL. This value was greater for non-ICU nurses (1.18 mL) than ICU nurses (0.96 mL), but this difference was not significant. We detected no significant association between hand surface area and preferred average dose volume. The ABHR dose volume was 0.006 mL less per use as the number of applications per shift increased (P = .007).

The average dose of ABHR used was similar to the dose provided by the hospital’s automated dispensers, which deliver 1.1 mL per dose. The volume of ABHR dose was inversely correlated with the number of applications of ABHR per shift and was not correlated with hand size. Further research to understand differences and drivers of ABHR volume preferences and whether automated ABHR dosing may create a risk for people with larger hands is warranted.