Impact of automated area decontamination on HAIs

Automated area decontamination systems are a valuable, user-friendly alternative to manual processes for surface disinfection

Healthcare-associated infections (HAIs) represent a significant clinical and economic burden. These infections can be contracted through contact with an infected or colonised individual, a contaminated environment, or a contaminated instrument.

Manual cleaning alone has been found to have limited effectiveness in the prevention of HAI transmission through the environment, and manual disinfection is unlikely to solve this problem due to inconsistencies in results and the margin for human error.

Automated area decontamination (AAD) systems, based on hydrogen peroxide (H2O2), represent a valuable disinfecting option and AAD systems using a low concentration of H2O2 are user-friendly, requiring little input to calculate cycle parameters, and without the need for external environmental control.(1)

Low-concentration AAD systems are also less likely to cause corrosion than wet disinfection methods, and capable of successfully eradicating pathogens of key concern and meeting levels required in a real-life hospital situation. Due to the growing interest in AAD as an alternative to manual disinfection procedures, there is a need for dedicated AAD benchmark guidelines, and an evaluation of the potential for use in routine practice is warranted.(2) 

This summary will refer to data for the GLOSAIR™ 400 System as an example of a low-concentration AAD system, for which published data support its effectiveness in field trials and clinical practice. This evaluation will be put in the context of the important role of the environment in the pathogenesis of HAIs.

A growing body of evidence supports the role of the environment in HAI pathogenesis and indicates surfaces in cross-contamination events.

In one study, Mutters et al showed a correlation between Clostridium difficile counts on the floor and on the hands of both patients and healthcare workers in a large hospital.(3)

In another study by Huang et al, it was found that patients receiving treatments in hospital rooms previously occupied by a meticillin-resistant Staphylococcus aureus (MRSA)-positive patient were at a 34% increased risk of contracting MRSA compared with patients treated in rooms where the previous occupant was MRSA-negative (adjusted odds ratio: 1.4, p=0.04).(4) A similar finding was made for another common HAI-related pathogen, vancomycin-resistant enterococcus (VRE).

When defining the appropriate efficacy level for AAD systems it is important to take into consideration the real-life contamination levels after manual cleaning. A recent study found that in clinical practice, the maximum contamination level observed is 3-log/25cm2, implying that a 4- or 5-log efficacy margin for disinfection systems would be appropriate, although 

a separate level could be defined for outbreak situations.(2)

Manual cleaning represents the established first step in any decontamination procedure. The effectiveness of cleaning in the removal of soil predominantly depends on mechanical action. This needs to be followed by a process of disinfection, which may be either manual or automated.

The limited effectiveness of manual cleaning alone has been noted in numerous studies. In a study by French et al, 74% of 359 swabs taken from surgical wards were positive for MRSA prior to manual cleaning. After manual methods were applied, 66% of the 124 swabs taken remained MRSA-positive.(5) A systematic review of area decontamination studies also revealed data that indicated a high level of incomplete pathogen removal with manual cleaning methods.(6)

 

Manual disinfection can expose healthcare employees to potentially damaging chemicals. The success of manual disinfection techniques depends upon the skill of the user, and it is often difficult to reach all potentially contaminated surfaces.(7) The inconsistency in effectiveness of manual disinfection with abundant margin for human error is an important consideration and reinforces the need to evaluate the potential of automated processes as an alternative in routine disinfection practice.

Automated area decontamination is a technique that can be used in conjunction with manual cleaning to reduce environmental bioburden. H2O2 is the biocidal agent commonly used by AAD systems, with both high concentration and low concentration systems having been developed.

AAD possesses a number of benefits as an alternative to manual disinfection. First, automation ensures that the level of disinfection achieved is consistent every time. Automated systems are also more pervasive than manual disinfection procedures. Low concentration AAD is less corrosive and safer for staff since it requires no contact with disinfecting chemicals.(1) Based on this, the technology deserves to be evaluated as a viable replacement for manual disinfection.

The AAD technology has been proven to be effective over several years of use in a number of different hospital situations and scenarios. The demonstrated value of AAD is exemplified through the low concentration GLOSAIR™ 400 System, manufactured by Advanced Sterilization Products (ASP). For this system, several field trials are available, and these are summarised in Table 1.

The GLOSAIR™ 400 System has also been widely used by healthcare facilities in routine practice for several years.

Nottingham University Hospital in the UK has incorporated the GLOSAIR™ 400 System in its disinfection procedures. This has been shown to have significantly reduced the number of cases of C. difficile infections and recently also resulted in the complete eradication of endemic and epidemic multi-resistant acinetobacter in a burns unit in the hospital.(16,17) 

The Royal Liverpool University Hospital introduced the GLOSAIR™ 400 System as part of their updated infection prevention procedures in November 2008.(18)  Between December 2008 and March 2009, the number of norovirus cases was significantly reduced and 1352 bed-days were saved, equating to total savings of approximately £650,000. Similarly, from April 2008 to March 2011, there were reductions in hospital-acquired C. difficile and MRSA cases of 80.5% and 86%, respectively.

Experiments were performed at two Italian healthcare locations in 2012, in which microbial load was measured across a variety of surfaces at two timepoints: after routine cleaning, and following environmental decontamination with the GLOSAIR™ 400 System. The results are summarised in Table 2. A reduction in microbial load between these two timepoints was found in all environments. These two experimental trials therefore demonstrate that automated environmental decontamination technology is able to contribute, along with traditional manual cleaning procedures, to minimising the microbial load present on surfaces in a real-life scenario.(19)

 

Based on the published literature, as well as the testing in these two centres, the Italian Association of Medical Directors (ANMDO) published a recommendation in Italy to consider the hydrogen peroxide mist system, which can effectively ensure(20):

 

A preventative action if combined with periodic decontamination through traditional cleaning methods in hospital areas, as it prevents the occurrence of HAIs

A totally eradicating action against the insurgence of pathogen-related epidemics, resulting in effective elimination of related infections.

Conclusions

There is increasing evidence supporting the role of the environment as a reservoir for infection. Increasing the intensity of manual disinfection does not represent an effective strategy for combating this, due to the inherently high variability of success of this technique. Automated area decontamination with low concentration H2O2, such as with the GLOSAIR™ 400 System, in addition to manual cleaning, has been shown to be an effective method to reduce bioburden and so represents a potential solution to the threat of environmental HAIs. Although causality is difficult to prove, evidence suggests a link between a reduction in pathogen levels with H2O2 AAD systems and the number of infections, and real-life evidence has shown the benefit in reducing bed-days lost due to HAIs. The economic impact associated with this is important and therefore warrants further investigation.

The growing interest in automated area decontamination technology produces a need for dedicated benchmark guidelines that evaluate the level of bioburden in clinical practice and determine cleaning standards accordingly, in order to maximise the benefit of this technology alongside manual cleaning.2 As the adoption and acceptance of AAD as an integral part of infection prevention continues to increase, more data will become available and this should facilitate continued evaluations of the success of this technology in hospital HAI prevention. 

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