There has been lots of debate over many years about the extent to which hospitals should provide single rooms for patients. Should every patient have a single room for the sake of privacy? Would this help to reduce HCAI? And would it be safe even if it did? A recent review suggests that more single rooms equals less HCAI.
The systematic review found that hospital wards with more single rooms had lower rates of HCAI. This makes sense: physical segregation of patients with infectious agents is an ancient approach to preventing transmission. However, whilst the evidence that single rooms reduces HCAI is compelling, there are other reasons why a mixture of single rooms and bays may be a better approach. Some patients benefit from the social aspects of communal bed-spaces. Also, when things go wrong, there is some evidence that patients in multi-occupancy bays are helped more quickly and have better outcomes.
On the balance of this evidence, it may be that a mixture of single rooms and bays is the best design for a hospital of the future. The UK recommends at least 50% single rooms for new hospitals, which would seem a sensible approach based on the current evidence!
A number of automated room decontamination (ARD) systems are available. Most of the evidence relates to hydrogen peroxide based or UV based systems. A new study reports on the impressive efficacy of an ARD system combining hydrogen peroxide and peracetic acid, achieving a 6-log reduction on bacterial endospores.
There is plenty of evidence that ARD systems using ‘high concentration’ hydrogen peroxide (typically 30-35%) are able to achieve a >6-log reduction in lab studies and eliminate pathogens from hospital surfaces. Meanwhile, ARD systems using ‘low concentration’ hydrogen peroxide (typically 5-6%) achieve a lower level of reduction in the lab (usually around 4 log) and reduce but don’t eliminate pathogens. However, low concentration hydrogen peroxide systems offer a number of potential advantages over higher concentration systems, including the potential for shorter cycles. An alternative approach is to use a mixture of chemicals to achieve a greater microbiological impact whilst being able to reduce the concentration of the chemicals involved.
The study in question tested an ARD system that uses 22% hydrogen peroxide combined with 4.5% peracetic acid. The combination of hydrogen peroxide and peracetic acid is a good idea because there is a natural synergy between these two chemical in delivering improved biocidal performance. Glass slides inoculated with 5-6 logs of key pathogens (including C. difficile spores) were placed at 10 locations around the room. In seven rooms cycles, all pathogens were inactivated (a >5-log reduction) from all locations (some of which were out of direct line of sight), with the exception of partially closed draws. Even in these draws, the concentration of pathogens was reduced. And all of this with a cycle time of 90 mins!
The concentrations of hydrogen peroxide and peracetic acid were still rather high in this study – it would be interesting to see whether comparable results could be achieve by reducing the concentration of the chemicals involved further! Could it be that peroxide / peracetic mixtures are a new kid on the ARD block?
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!
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.