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.)
(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.
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.
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!