The Role of Contaminated Surfaces in the Transmission of Nosocomial Pathogens - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 45

3.8 Environmental Cleaning, Disinfection
and Infection Control

3.8.1 Improving the Efficacy of Cleaning and Disinfection

Cleaning and disinfection rarely eliminates pathogens and the baseline cleaning
rate for high-risk objects in a large study of 36 acute US hospitals was 50 %, as

determined by removal of a fluorescent marker [ 129 ]. Several studies have demon-
strated that focused efforts can improve the efficacy of cleaning. For example,
Eckstein et al. found that a research team was able to eliminate persistent VRE and
C. difficile from surfaces while a housekeeping team did not [ 32 ]. Furthermore, a
number of studies have shown that systematic education and monitoring of
the cleaning and disinfection process can reduce contamination of surfaces and
transmission (Table 3.4 )[ 13 , 82 , 103 , 106 ].
There are several different options to monitor the effectiveness of cleaning, each
with advantages and disadvantages. These include visual monitoring, microbio-
logical sampling, fluorescent markers and ATP bioluminescence assays (Table 3.5 )
[ 130 , 131 ].
Visual assessment of hospital cleaning is performed by measuring the apparent
cleanliness of a room against a checklist [ 132 , 133 ]. Visual inspection is important
since a room needs to be visually clean to be acceptable to the current and
subsequent occupant. However, visual assessment of hygiene does not correlate
with microbial contamination, and can thus be a misleading measure of cleanliness
[ 64 , 134 , 135 ].
Microbiological surface cultures can be qualitative (pathogen presence or
absence) or quantitative (aerobic colony counts). Several different sampling
methods are available; usually swabs (with or without enrichment) or contact
plates. Quality standards for both aerobic colony counts (

<

2.5 CFU/cm 2 ) and

<

1 CFU/cm 2 ) have been proposed [ 133 , 136 ].
Standards exist for the quality of air in operating theatres [ 137 ] but cost and
practicality mean that routine microbiological sampling outside of operating
theatres is rarely performed.

specific indicator organisms (

<

Table 3.5 Comparing the options for assessing the efficacy of conventional cleaning and
disinfection

Visual Micro ATP Fluorescent

Ease of use High Low-moderate High High

Quantitative No Yes/no Yes No

Correlation with microbial contamination Poor Accurate Indirect Indirect

Identifies pathogens No Yes/no No No

Risk of “gaming” by staff Low Low Low Moderate

Identifies 'dirty' surfaces a Yes No Yes No

Published evidence of attributable
clinical impact

No Yes [ 106 ] No No

a non-microbial soiling