Cost-effectiveness of C. difficile prevention

How much does it cost to prevent the transmission of C. difficile? And is switching to an automated room decontamination (ARD) system for the prevention to reduce environmental contamination with C. difficile spores cost effective? Whilst no formal cost-effectiveness evaluations have been published, there is enough evidence to suggest that switching to an automated room decontamination system will be cost-effective given the published scale of reduction in C. difficile transmission, and the per-case cost of C. difficle infection.
 
C. difficile infection can be an extremely expensive outcome for a patient. Leaving aside the important socioeconomic impact for the individual and obvious human cost, a recent review suggests that each case costs somewhere between £2000 and 19,500. A number of studies have shown that automated room decon systems reduce the incidence of CDI (see the summary table below). Whilst these studies are really non-comparable – performed in different settings, with a different baseline rate of CDI, and a different set of background interventions, a crude mean percentage reduction was 44%. (Incidentally, this suggests that 44% of CDI is related, directly or indirectly, to contaminated environmental surfaces, which is interesting in itself.)

jon-table-18-11-16 (Click on the table to enlarge)
 
So, let’s take a hospital with 50 cases of CDI each year. If an ARD system is introduced for the terminal disinfection of rooms following the stay of a patient with CDI, you would expect a 44% reduction in the number of cases, and only 28 cases of CDI – hence 22 cases averted. This would result in a cost saving in the range of £44,000 – £429,000. Taking a mid-point of this range (£240,000) leaves a pretty large envelope in which to fit an ARD service to ensure that all rooms occupied by patients with CDI are decontaminated. Furthermore, it is likely that a service could cover discharges with other pathogens and make an impact on them to – delivering further financial savings.

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One final thought: does an infection prevention initiative have to be cost-saving? Or is it acceptable for a prevention initiative to cost more than the associated financial savings? I guess this will depend on the circumstances and the costs involved on both sides of the equation, but it won’t always make sense to accept only cost saving prevention initiatives.
 

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Does chlorhexidine resistance emerge in Staph aureus?

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It is prudent to be concerned that regular use of chlorhexidine will ultimately result in reduced chlorhexidine susceptibility and perhaps even resistance. However, a recent long term study performed over a decade in the north of England suggests that regular use of chlorhexidine as part of an MRSA decolonisation regieme does not result in widespread reduced susceptibility.

The regional study in the Yorkshire and Humber region collected a ‘snapshot’ of S. aureus isolates from 14 laboratories over two days. The isolates were tested for their in vitro susceptibility to chlorhexidine, and the carriage of the qacA gene, which has been associated with reduced chlorhexidine susceptibility. Overall, 1.7% of the 520 isolates carried the qacA gene, and 3.5% had a chlorhexidine minimum inhibitory concentration (MIC) of >2. Whilst there is no clinically defined breakpoint for chlorhexidine resistance, an MIC of >2 is generally considered to be reduced susceptibility. Similar findings were reported for mupiricin, with low levels of in vitro mupirocin resistance detected.

So, despite the widespread use of chlorhexidine for decolonisation of S. aureus carriage in the region, reduced susceptibility was not widespread. Does this mean that reduced susceptibility to chlorhexidine isn’t a problem? No, we know from other studies that it can be. It’s just that it seems to be a rather rare event, at least in the north of England!

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Further evidence to support the clinical impact of a UV-C disinfection system

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A new study has just been published in Infection Control and Hospital Epidemiology that provides further evidence that the introduction of a UV-C disinfection system (Optimum-UV, marketed in the UK as the Clinell UV-360) has a clinical impact on the rate of CDI.

The design was a 2 year prospective pre-post intervention study in a 789-bedded tertiary referral centre in the USA. The intervention was implemented in the haematology wards, the researchers using the rest of the hospital as a control. The UV technology was used for terminal cleaning of patient rooms, primarily targeting those rooms where patients were on contact precautions for Clostridium difficile infections. Rooms of patients on contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococcus (VRE) received secondary priority for UV deployment. To ensure adequate exposure of UV light, UV dose cards placed throughout the patient room were used to verify the cycle times. The study was controlled for potentially confounding variables like hand hygiene
compliance and antibiotic usage.

The results showed that there was a 25% reduction on the study units, and a 16% increase on the control units and an adjusted analysis found a significant association between UV treatment and a reduction in the rate of CDI. The adjusted analysis that accounts for more variables demonstrated that the reduction in CDI was statistically significant. Another additional and important finding was that the use of UV had no detrimental effect on room turnaround times, with an increase in less than six minutes overall for rooms in which the device was deployed. Following the 12-month evaluation period, the hospital implemented hospital-wide use of the UV technology, purchasing three UV devices, hiring 3.5 workers for the deployment. This has resulted in 53 less cases of  C. difficile  infection than the previous year with an associated annual direct cost averted of US$348,528 to $1,537,000.

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Infection Prevention 2016: a bug’s eye view

Another IPS conference has been and gone, and what a lot of fun and learning to be had! New research published, new products launched, and new contacts made – all in a few days in sunny Harrogate.

Several of the lectures were outstanding: Prof Gary French on the ‘swing’ away from antibiotic-resistant Gram-positive bacteria towards Gram-negatives, Prof Eli Perencevich on measuring and improving hand hygiene, plus inspiring lectures from both IPS patrons (Professors Hart and Pittet). It’s great to see all of the submitted abstracts published in a Journal of Infection Prevention supplement. Here’s a few highlights from the abstracts:

  • ‘Room staging’ (the location of a UV device) is vital in terms of maximising efficacy (#4652).
  • Laboratory testing of disinfectants needs to consider the impact of biofilms on dry hospital surfaces (#4624 on the efficacy of superoxidised water, and #4640 on developing meaningful laboratory tests for disinfectants accounting for biofilms).
  • Further evidence that simple, educational interventions can make a dramatic impact on the effectiveness of cleaning, in this case, increasing fluorescent spot removal from <30% to >70% (#4484).
  • The effective roll out of Clinell Universal wipes across an acute NHS hospital and associated community healthcare providers to develop a ‘city-wide’ approach to cleaning and disinfection (#4596).
  • Gama launched a number of new products at the conference. Finding a sporicidal disinfectant that is safe, effective, and well-tolerated by patients, staff and the environment is challenging. Sodium hypochlorite ticks some of these boxes, but is by no means perfect: it is inactivated readily by biological soiling, has staff exposure issues, and is not environmentally friendly. And so we have introduced a peractic acid based sporicidal disinfectant that ticks all of these boxes. The arrival of the Clinell Sporicidal Granules prompted a protest…from the bugs!

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    Gama is committed to the importance of training and understand that easy-to-use and up-to-date training materials are a vital resource. With this in mind, we have launched a re-vamped training module, that is designed to be configured to your needs, whether you have 5 or 50 minutes to deliver a training session. The material for the modules has been formulated by Martin Kiernan, our clinical director, and is updated regularly via the tablet-based platform.

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    Finally, we would like to congratulate the brainy winners of the quiz on our stand:

    Day 1: Karen Hawker

    Day 2: Kirsty Louise Morgan

    Day 3: Jean Robinson

    The vision of IPS that ‘nobody is harmed by a preventable infection’ is one that we can all subscribe to, so roll on Infection Prevention 2017!

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    Is it sporicidal?

    c-diff
    Prions aside, bacterial endospores are generally considered to be the toughest challenge for disinfectants. Consequently, they are used as the ‘gold standard’ for disinfectant testing; if it can kill bacterial endospores, you make the assumption that it can kill everything else besides. However, how do we know which disinfectants are sporicidal?

     
    Bacterial endospores are ‘survival structures’ produced by only a few types of bacteria (including Clostridium difficile, which is the most important spore-former in the context of hospital cleaning and disinfection). Spores are resistant to many of the chemicals used for hand and surface disinfection in hospitals, including alcohol and quaternary ammonium compounds. Therefore, soap and water hand washing is recommended when caring for a patient with C. difficile (or gastro-intestinal symptoms of unknown origin), and a sporicidal disinfectant for surface hygiene (such as peracetic acid or hydrogen peroxide).

    To be classified as a sporicide, a disinfectant must meet be able to pass a sporicidal disinfectant test. Whilst a number of different sporicidal testing standards are available, they share core methodology: testing a particular disinfectant formulation against spores of a known quantity, for a set period of contact time, with appropriate neutralisation to prevent ‘over-exposure’ of the spores to the disinfectant, and under controlled laboratory conditions. It is important to note that “non-sporicidal” disinfectants will be able to kill some of the spores in a laboratory test, so if these testing conditions are not controlled appropriately, they may appear to be sporcidial even when they are not. This was illustrated by a fairly recent study, which showed that many wipes that claimed to be sporicidal were not when tested under standardised laboratory conditions. The study also highlighted the importance of the wipe material in preventing the transfer of organisms from surface to surface – highlighting that the Gama sporicidal wipe was the most effective at preventing the transfer of organisms between surfaces. Another recent study highlight the importance of appropriate neutralisation in sporicidal disinfectant testing. Quaternary ammonium compounds when combined with amines appeared to be sporicidal in initial testing, which would be a major development in the range of disinfectant available. However, subsequent testing demonstrated that this was due to inadequate neutralisation of the disinfectant – so it turns out that quaternary ammonium compounds combined with amines are not sporicidal after all!

    So, some key questions that you should ask when reviewing whether a sporicidal claim for a disinfectant is legitimate are:

    · Did the test match the proposed usage of the product? For example, a laboratory test that evaluates the ability of a liquid disinfectant against a liquid suspension of spores is not representative of a disinfectant-impregnated wipe being used to disinfect surface attached spores!

    · Is the contact time representative of in-use recommendations (or practice)? A disinfectant that is sporicidal only following a 60 minute contact time cannot be considered sporicidal in real terms for hospital surface disinfection.

    · Has the disinfectant been neutralised appropriately? If not, the laboratory test will over-expose the spores to the disinfectant, and over-estimate the sporicidal capability of the disinfectant.

    · Was the testing performed by a reputable laboratory?

    Sporicidal wipes offer the potential to reduce reliance on the operative to assure correct formulation of a disinfectant, and are likely to improve compliance cleaning protocols due to the convenience factor. However, we need to be sure.
      

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